This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------ This text file gives users' tips and discusses various methods of indicating, centering, locating, and/or measuring a workpiece or tool position. If you got to this file directly from my HOME PAGE, return there by using your browser's back button. BUT if you came to this file as the result of a web search engine, see many additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/index.html SAFETY WARNING BEWARE: DO NOT ASSUME that any subject matter or procedure or process is safe or correct or appropriate just because it was mentioned in a news/user group or was included in these files or on this site or on any other web site or was published in a magazine or book or video. 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(c) Copyright 2003 - 2015 Machining and Metalworking at Home The form of the collected work in this text file (including editing, additions, and notes) is copyrighted and this file is not to be reproduced by any means, including electronic, without written permission except for strictly personal use. ========================================================================== From: Date: Sun Dec 5, 1999 4:03pm Subject: Re: Shop Tip In a message dated 12/5/99, eidolonx~xxe... writes: << Does everyone know how to use a DTI for mill centering between two opposite edges without having to know/calculate out backlash? >> If for example you have a piece with two parallel sides you can place an angle plate on one side against the work piece. Then you can indicate the other side of the workpiece, then the side of the angleplate for the other side, using both measurements approaching from the same direction, I hope this what you meant with your question. bill ------- From: Date: Sun Dec 5, 1999 4:03pm Subject: Re: Shop Tip In a message dated 12/5/99, cmsteamx~xxa... writes: << Does everyone know and use the Bedside Reader Tip on using cigarette paper for work location? >> I use it all the time on the mill for all axis. Long before the bedside reader came out. Most of the hints are in earlier Popular Mechanics Shopnotes from the 50's and earlier. Anyone got any of them for sale? Contact off list. In using the lathe, I use a tool to get very close with the four jaw, then if needed I get the DTI out and go from there, the tool bit is usually very fast, and you can make direct measurements from the cross slide, and this way you don't overtravel the DTI, which can be a real danger to it. ------- From: Date: Sun Dec 5, 1999 4:30pm Subject: Re: Shop Tip In a message dated 12/5/99, WAnlikerx~xxa... writes: <> I should have added the line, take the reading derived from those two locations, divide by two, and add to the indicated location, to get the center line, again approaching from the same direction. bill ------- From: Steve Clark Date: Mon Dec 6, 1999 10:01am Subject: Re: Shop Tip [Note: think he may have been alluding to a much earlier post as to wrong method here.] Unfortunately, this method will leave you off center by 0.5 times the dial test indicator ball. The method I use is to zero my hand wheel by turning past 0 by about 5 thousands on the test indidator, then set the zero as I crank away form the workpiece center. After this, I move to the other side and record the reading as I crank toward the workpiece center. This way both zeros are found while cranking in the same direction - thus eliminating backlash. The total reading you will get is actually the workpiece width plus the test indicator ball diameter, but when dividing by two the ball diameter cancels out giving the true center location. If you do this in this order (away from center then toward center), you can go directly to the center point rather than having to crank past and back up. ------- From: Gregory Gagarin Date: Mon Dec 6, 1999 11:08pm Subject: Re: Shop Tip -- Revisited When I mentioned these two (5&6) subjects I assumed (as is often the case) that something I only discovered, or figured out, recently had been known by everyone else since the beginning of time. I think that's true about 5. (Rich Dean has a refinement of the idea) but I'm not so sure about 6. so I'll send up a trial balloon for the pros to shoot at. About 2 months ago I had a large semi-finished cylindrical piece of stock mounted horizontally (attached to an angle plate) on my mill oriented lengthwise along the X axis. I needed to center the spindle VERY accurately (in the Y axis) over the stock to mill it along its X axis on center. My edgefinder shoulder would not clear the cylindrical edge and I wanted to avoid using backlash numbers in the calculations -- I've never trusted them to be consistent in different locations of the lead screws. After a lot of head scratching, I came up with a technique that worked so well that I use it routinely now when I have to be very precise in centering or want to avoid marking work surfaces(as with edge finder): 1. Set the Y handwheel such that it reads "0" when the ruled scale (on the Y axis bed) is on one of the graduated lines. Now you can read out a complete relative Y axis position and don't have to count handwheel revolutions. 2. Mount a DTI in the spindle offset such that it sweeps a small (about 1") circle at the tip and with the tip pointing near vertical (for sensitivity)slightly outside the circle. 3. Move up to the stock, sweeping the spindle (and DTI) until the DTI just touches the stock on its sweep and adjust the Z axis to the required test point (max deflection to center on a cylinder). 4. Use clockwise rotation to move the spindle closer until the DTI reads some convienient number (say 10) as a max value when swept by the stock. Your stock is now 10 thousandths inside the circle around the center of the spindle. Record the Y position (scale + handwheel) as you would on a dial caliper. This is your front relative position. 5. Move the spindle/DTI to the other side of the stock without disturbing the DTI setup. You can go around or over, or both, but you then must return the X and Z to the same settings you started with (in front) after you get it to the other side. 6. Back the spindle/DTI (counterclockwise Y handwheel turns)until the sweep shows the same maximum number on the DTI. Now take out the backlash by continuing moving the spindle in to say "25" (more than the expected backlash beyond the desired "10") then reverse and go back to the "10". You have now taken out the backlash and returned to the same offset on the backside as you had on the front. Record this rear relative position (scale + handwheel as before). 7. Subtract the smaller position from the larger position -- divide by 2 -- add this to the smaller position (or subtract from the larger). This is the desired center position -- scale + handwheel. Note: you never determined or needed the stock width. 8. Remove the DTI and move the Y axis to the above position using the scale and handwheel values and finishing with clockwise rotation. DONE. This takes a lot longer to describe than to do. Just don't forget that the key is in sweeping the edges (not static measurements) as we are looking for measurements along the intersecting edge and circumference of the DTI arc and not to disturb the DTI in the spindle or it's point setting. With slight modification this procedure can be used on non-parallel edges to find the center between two points on the edges. That's another story. I have only gone to this length in description since DTIs and such arrive without instructions and, for me, work locating has been a chalenging experience of discovery. Hope someone finds this helpful. Greg ------- Date: Thu, 18 Jan 2001 15:25:21 EST From: wanlikerx~xxaol.com Subject: Re: Centering a Rotary Table Make a plug that will fit the rotary table center hole very accurately, with a center cross scribed on it. Put the plug in the rotary table, then use a center finder in the spindle to find that center and fasten it down. There are several types of commercial and home built center- finders available, but in an emergency put a blob of clay on the end of the spindle, and insert a pin, center the sharp end by turning slowly and use a piece of metal to get the end of it to spin accurately on center, with no wobble. Carefully line the two up, and you can end up very accurate. Use a magnifying glass, but don't dislodge the pin, could hurt you. This is known in the ME magazine as a sticky pin, centerfinder, and it works well, if used carefully, don't spin too fast. bill ------- Date: Thu, 18 Jan 2001 19:38:17 EST From: sgut1x~xxaol.com Subject: Re: Centering a Rotary Table Gavin, I put a dial indicator in the spindle and roughly center the rotary table under it so that the indicator tip just touches the inside of the hole in the center of the rotary table. After that you simply move the x or y axis a bit then rotate the indicator along the inside of the hole. If the needle moves, you adjust along the axis using the handwheels. Once you've dialed in one axis you dial in the other. This might sound confusing but it is really quite intuitive once you try it. I think centering the rotary table is rather fun because you can move it so precisely using the x and y axis feeds. You can effortlessly move that .0005 needle until it is perfectly still. It sure beats tapping ever so gently with a hammer on one side of say a vise then tapping ever so slightly on the other side to line it up. Hope this helps, Stephen G. ------- Date: Thu, 18 Jan 2001 21:04:23 -0500 From: ron ginger Subject: Re: Centering a Rotary Table Gavin Eyre wrote: > Can anyone give me some suggestions on the best way to center a > rotary table so that the axis is aligned with the Z-Axis of the > mill? I am making a number of small connecting rods for an O gauge > loco and need to be able to mill small circular areas at the ends of > the various rods and links. Depends on how exact you need it. If all you are doing is the outside of a rod end, then I would turn a simple cylinder with one end the dia of the tables center hole, the other end 3/8" , or whatever end mill you plan to use. Id stick this into the mill collet, the other end into the rotary table, then I tighten the clamps and lock the table down. I suspect this will put it within 2-3 thou. If it needs to be 'spot on' to within a thou or less, then use an edge finder, and the 'Osbourne manouver" I think its called. First you need to accurately know the diameter of your table, then you set the mill to an 'eye-ball' of the center. Next you go to one edge of the table, say X first, pickup the edge, set your DRO to zero (you do have a DRO of course:-) then go to the opposite edge, find it. Take the distance moved, divide by 2, and move X back to that location. Repeat the steps, this time on the Y axis. Repeat again in both X and Y, and you are about as close as you will ever get. This requires an edge finder, which is a fairly cheap tool and very worthwile for a mill. ron ginger See Guy Lautards Second Bedside Reader for an explanation of this, including some math to prove its as close as you can measure in only 2 or 3 moves. ------- Date: Fri, 19 Jan 2001 16:19:54 -0000 From: khgrantx~xxix.netcom.com Subject: Rotary Table tolerances? The discussion about centering the rotary table reminds me that the last time I tried to center mine, I noticed that the center hole was not exactly concentric with the rotation. Indicating on the inside edge of the hole and rotating the table resulted in an eccentricity of about 0.0005 or more (it was several months or more ago; I don't remember the exact figure). What do others see with thier Sherline rotaries? The other thing I noted at the time was that the surface of the table wobbled a bit as it rotated. That is, with indicator in spindle, indicate off the top surface of the rotary table near the outer diameter. Rotate table and note deflection. I don't remember the value, but I was disappointed in the amount of runout. What do others see for this value? Keith ------- Date: Wed, 14 Feb 2001 16:11:54 -0800 From: Alan Marconett KM6VV Subject: Re: Wiggler. Hi Rogerio, As I understand it, the sharp tip of the wiggler is first set true by running the spindle relatively slow, and "pushing" on the tip with a piece of metal. Once running true, you can shut off the spindle motor, and bring the tip down near a cross hair scribe on a part. Use an 8x loupe (unless your eyes are better then mine), and move in X & Y until centered underneath the sharp tip (but don't disturb the tip!). There are other "tips" in the wiggler bag, the "small cyl" one can be "trued" as above, and kept spinning, brought up next to an edge, and when it just touches, it will "flail" out of true. Wigglers don't themselves "find" the center of a part; you can find the edges, and "dial" over to the center (do X, then Y), given the dimensions of the part. Hope this gets you cutting! Alan KM6VV P.S. Any more uses? I'd like to hear about them also! ------- Date: Wed, 14 Feb 2001 22:27:01 -0500 From: "Marshall Pharoah" Subject: Re: Wiggler. I've been using one for a few months now. I true up the needle point with my thumbnail. Therwise, just like Alan said. The round ball tip is a good edge finder, as is the .100 cylinder. These I find work best to let them wobble quite a bit. As you move the work closer to the wiggler you'll hear it start ticking. Eventually the ticking stops as it rubs constantly. Slightly closer and the ball (or cylinder) will jump to the side. I think this is actually the same motion an edgefinder works on. The bent shank unit is actually an indicator holder I've been told, but haven't really used it yet. To use it to find the center of a solid bar held vertically in the vise, you would be looking for one side and front or back. There is a hunt algorithm that works for this, but I don't have the book handy. I usually just use a lathe to find the center. Marshall ------- Date: Wed, 14 Feb 2001 22:05:56 -0600 From: "Al Lenz" Subject: RE: finding the center of a hole ( was Wiggler). Marshall and list, Just how is the best way to find the center of a drilled hole? The other day I lost my coordinates and had to re-zero on a 10-32 tapped hole. I know that I have read a dozen posts on the best way to do this, but suddently went brain dead. I put a dead center in the spindle and lowered it down til it "looked good". That didn't seem very scientific. Then, took a 10-32 cap-screw and turned the head true. Screwed it into the hole and then used and an edge finder to locate. This was OK for the purpose, but that isn't what I'm trying to remember, (or is it?) Al PS. The part was a 3 X 3 X 3/4 piece of scrap 6061-T6 that turned into a $375 part for my son's 928 Porsche. It fit "like it was made for it". The first "REAL" part made with my new CNC setup. And these are toys? ------ Date: Wed, 14 Feb 2001 20:36:05 -0800 From: Alan Marconett KM6VV Subject: Re: finding the center of a hole ( was Wiggler). Al, What's the Porche part? I've used a "dead center" before, I'm told you can still be off a few thousands. The cap-screw with "trued" head sounds like using what I think they call a "button". Should work great! You can indicate three points on the inside of a "clean" hole, and calculate the center, but with threads?? I don't think so. Alan KM6VV ------- Date: Wed, 14 Feb 2001 21:35:14 -0800 From: "YK Chan" Subject: Re: finding the center of a hole ( was Wiggler). Here is my two cents. Preparation: Bearing ball: 1X < dia. < 2X. Steel plate or USA razor blade. Dead center. Action: Chuck or collect a dead center to the mill/drill. Place the ball on the hole. Move the dead center tip above the ball. Place the blade on top of ball. Drop the mill to GENTLY hold the blade. Any off center will show up on the blade plane. Adjust until blade is horizontal to the mill table. End of Action. YK Chan in Seattle area. ------- Date: Thu, 15 Feb 2001 00:33:52 -0600 From: "Al Lenz" Subject: RE: finding the center of a hole ( was Wiggler). To YK, thanks, that is excellent. Your idea would have been quicker and better. The hole was drilled, tapped and chamfered, just perfect for your application. Your tip will be useful "next time". To Alan, the 928 has a rather unique coupler in the steering shaft that only comes as an assembly, thus the high cost. My son did it up in Autocad and we watched in awe as it was cut. Sort of a rounded corner square piece with raised oblong lands and oblong holes. Four 8 mm slotted holes cut with a 1/4 end mill, (couldn't do that without CNC). HAVE done similar with a file tho no comparison to the accurate final result. al ------- Date: Thu, 15 Feb 2001 12:18:41 -0000 From: ballendox~xxyahoo.com Subject: Re: finding the center of a hole ( was Wiggler). Al, lotta answers to your simple question. small hole, big hole, threaded, not threaded. Accuracy needed. All these need to be part of the answer. Having said that, there are precision equivalents of your "turned capscrew" that are used as you used yours. A "shoulder screw works well if you have one in the right thread size. Also many machinists carry sets of threaded "transfer points", which can be used with a wiggler or "center finder end" of an edge finder. The cone of the center finder will work with (is designed for) small holes. Threads will mess it up, tho; so it only is good for drilled/reamed/bored holes. Larger holes can be edge-findered in three points, with geometry filling in the gap... (remember that a right angle whose vertex is on the circle, will have 'legs' which intersect the circle on the diameter.) Halfway between the two points which make the diameter is the center. Hope this helps. Ballendo ------- Date: Thu, 15 Feb 2001 12:32:30 -0000 From: ballendox~xxyahoo.com Subject: Re: finding the center of a hole ( was Wiggler). YK, this is an excellent method as long as the hole edge (AND your dead center) is "sharp". And the material is FLAT. You can use any "true" point in the spindle... A similar technique is used to set tool height on the lathe. Chuck the material, blade is vertical between tool and work; when blade is vertical, tool POINT is AT center of stock. Also to get the tailstock back to center after an offset. With the sherline, you can put the point in the spindle and tailstock, with the blade in between, BUT... this will only align the headstock to the tailstock! Fine for between centers work. If the tailstock is not accurate, turning with a chuck could create tapers using this method of alignment. Use a test bar, and/or indicator... Thin steel shim stock can replace the razor. Hope this helps. Ballendo ------- Date: Thu, 15 Feb 2001 13:00:00 -0000 From: ballendox~xxyahoo.com Subject: Re: finding the center of a hole ( was Wiggler). > The cap-screw with "trued" head sounds like using what I > think they call a "button". Alan A tool makers "button" is a different thing. It is used to 'set up' a hole location more accurately than scribing, not to "find" an already machined hole. It is essentially a ground round bushing, with a screw through the middle, with "play" between the two. In use, the work is marked out and scribed as usual. Holes are drilled and tapped in the location(s) where button(s) will be used for ACCURATE location. The buttons are screwed into place, and snugged down... next the buttons are "adjusted" into accurate position (according to the part drawing) using whatever means of measurement makes sense. For example, say you have two holes which need to be EXACTLY one inch apart. You have placed two 1/2" diameter buttons in rough position. First you get one button adjusted until it is centered on the desired 1st hole position. Then, you 'mike' ACROSS the buttons "adjusting" until you have a reading of 1.500 inches. The buttons can now be used to 'dial in' the position AT the hole-making machine. AFTER the hole location is dialed in, the button is removed and the REAL hole is machined. This is a simplified explanation; most older machinist texts will detail the procedure. We don't see these as often now because our "commercial" cnc tools are so accurate, that we just program 'em, check 'em, and trust 'em... But it's a useful thing to have in your bag of tricks... Hope this helps. Ballendo ------- Date: Thu, 15 Feb 2001 08:23:51 -0500 From: "Marshall Pharoah" Subject: RE: finding the center of a hole ( was Wiggler). A Blake Co-ax indicator would probably be the best method. Second best would be a chinese clone of same (requires rework before use). For us ordinary mortals, a regular DTI mounted on an arbor in the spindle will work. You just spin it, adjusting the table as required until you get a zero reading, or as close as you feel works. You will either need a small mirror to read the indicator, or suffer a twisted neck. (don't spin it under power!). Another method I use which might be frowned upon, but has worked well for me is a low tech approach. I have a series of precision ground drill rod which fits the collets on my mill/lathe. This is ordinary O-1, but W-1 or A-1 would work, it's the precision ground that makes it work. This should be in the collet or mill holder and be tight enough that it sticks, but loose enough that you can grab it and slide it by hand. Anyway, If the hole I need to indicate in is the same size as one of these, then its just a matter of zdjusting the table until it drops in without binding. Otherwise I turn a tight bushing. This probably get you within a couple of thou, depending on the tolerances of your bushing, etc. You can also use a solid shaft which fits tightly in the hole, or toolmakers buttons if you have them and the hole is the right size, and then use an edge finder. The DTI is the preferred method. Marshall ------- Date: Thu, 15 Feb 2001 08:30:20 -0500 From: "Marshall Pharoah" Subject: Re: finding the center of a hole ( was Wiggler). I covered the first part of you question, but forgot about the tapped hole. By the very nature of tapping the hole, you've lost the exact center. Taps will cut a few tenth too one side or the other at least. What you did was probably close enough. There are precision tools made to do the same thing, but not worth the bucks unless you do it a lot, or need more accuracy. Marshall ------- Date: Fri, 16 Feb 2001 19:18:05 -0800 From: "YK Chan" Subject: Re: finding the center of a hole ( was Wiggler). Thanks to the update, tapped hole is not good for the ball anyway. As far as the subject it addressed the problem. In case of tapped hole, "ball ended" a correct size threaded rod to represent the ball. Hint, place a "true" nut to take out the slag between the hole and the rod should optimize the result. Hope that helps. YK ------- Date: Tue, 20 Feb 2001 15:17:06 -0800 From: Dave Martindale Subject: Re: Re: Problems Fly Cutting At 15:50 20/02/01 -0500, you wrote: >oI recognized the problem as being >an out-of-alignment situation with my milling head, so I pulled out a >piece of 1/4" optical flat glass (heavy, and supposedly true) and >pluncked it on my milling table. Using a dial test indicator, I got the >head trued up left to right, but then I found the readings front and >back were lower than along the length of the table. > It finally dawned on me that the weight of the glass was deflecting >it as it hung out over the front and back edges of the table. I then >shimmed things so the deflection was even on both the front and back >when the plate was equally positioned. Things have worked well since. You might want to check the flatness of the glass even when it's not overhanging the edge of a table. True "optical flats" are flat to a few wavelengths of light or less - better than a good surface plate. But to be stiff enough to hold that shape, their thickness is about 1/4 their diameter. Melles Griot (one vendor of optical flats) sells ones that are 6 mm (about 1/4 inch) thick, but they're only 25 mm in diameter. For 4 inches diameter, the thickness is 3/4 inch. There's no way 1/4 inch glass is stiff enough to remain optically flat if it's larger than this. Various people use glass plates for lapping things flat, and Lee Valley even sells a piece of 1/4 inch glass the size of a piece of sandpaper, but it's really not flat enough for machine alignment. Just putting a test indicator on a stand, with the indicator point a few inches from the stand, shows a few thousandths change as I move it around the plate. And if I lift it up and look at it nearly on edge, I can see distortion in the image reflected from the plate. I don't even use it for sharpening any more - I use the thicker plate below or a granite surface plate to back up the sandpaper. On the other hand, I have a piece of about 4x10 inch by 1/2 inch thick smoked plat glass, and it's as flat as I can measure (and looks flat in the reflection-on-edge test). This one might be good enough for machine alignment. Dave ------- Date: Thu, 22 Feb 2001 00:22:48 -0500 From: Stan Stocker Subject: Centering the tailstock, several methods WAS:Re: Setting up the Lathe I do a fair bit of tweaking/restoring and rebuilding of lathes so here's my somewhat long winded two cents (S&H included) worth. Using assorted techniques, I have made a number of parts that involve drilling holes to remove most of the center of a shaft, although there is usually 10 to 15 thou wall thickness left. Poking a 5 thou hole in a 9 thou shaft isn't on the list of stunts I've tried, although drilling 1/16 (0.0625) holes in the end of shafts turned to 0.080 is on the list. Indicating the results on a surface plate with a V block showed concentricity to within 2 tenths. Precision Test Bar methods and Gotchas: A precision test bar combined with a tenths reading dial indicator is the best all around, provided you have centers of known quality, or cut a 60 degree headstock center as part of the process. I prefer to cut the headstock center as on old lathes you never know who's done what, where, or to what standard of accuracy. Cutting your own center ensures the point is on the spindle center of rotation. Just don't unmount and remount the newly cut center! Many variables are eliminated by cutting the center. If the tailstock center is higher or lower than the spindle center, watch out for errors introduced by this. If only a matter of a few thou, using a button head on the indicator will avoid the error, combined with using the largest reasonable diameter test bar. If it's more than a few thou fix the problem. Note that some larger lathes have the tailstock 3 thou high when built. I made bars in several diameters to handle just this situation, and to avoid droop in the center of the bar. A 1/4 inch test bar spanning 10 inches is going to flex and droop, a one inch bar won't unless you do something silly, or want to chase far finer than tenths. Note that you can't make a precision test rod for use between centers without a steady rest. You can come close, but the 60 degree hole for the centers really must be bored using the compound, not drilled from the tailstock, while the blank is running on its perimeter. You also need a lathe with several inches more length than the length of the shaft to be bored. Start with some centerless ground stock. Verify it is truly round and dead straight using a surface plate and V blocks. One completed, never spin a test rod on the centers, by hand or under power. If you lightly oil the centers, you can gently turn the bar on stationary centers while indicating the perimeter to satisfy yourself that it is true and straight. The tailstock on the Taig is an odd little beast (no offense here, it is just different). Examine the tailstock center cone closely to ensure no burrs, crud, oil varnish, etc. At least you don't have to sweat indicating the interior of a morse taper or have a standards grade piece of MT tooling known concentric to the axis of the taper! The down side is that if you bugger up the tailstock center, you make or buy a new tailstock ram, or spend some time getting to know your toolpost grinder (on a lathe that can swallow the ram, the Taig can't). Indicating the Tailstock Center: Lacking a precision test bar, or when dealing with a worn lathe, swinging a test indicator from the spindle is a very good way to get things in line. I use this method often for non critical work, it will get you to well under a thou with care in short order. Simply swing front and rear, note the difference, and adjust half the distance. Repeat until dead on or close enough. On a worn lathe, this will give a trustworthy setting to allow the test bar to be used to verify the carriage isn't wandering about on a worn or incorrectly planed/ground bed. Cutting Test Bars (two rings, taper, assorted approaches abound). I reserve cutting test bars (the two rings method) for verifying the overall behavior of the lathe, as this introduces possible issues with loose gibs, cutter wear, bed twist, and the like. It is certainly valid, and is one of several final proofs that the lathe is set up correctly overall. The problem is that you may see a result due to something other than tailstock alignment and try to adjust it out and end up hiding an issue that will bite you later. As the Taig bed is more of a clockmakers style this is less of an issue, bed twist and leveling are not something that usually comes into play. Centering Drills - Not always the same as centering the tailstock center!: If you must center a drill on the spindle centerline, don't overlook swinging an indicator on a bit of drill rod of the same size as drill bit to be used held in the drill chuck. This will allow you to tweak out some of the variation inherent in using a drill chuck. This is particularly useful when drilling a hole that is nearly the size of the shaft to be drilled. Do your best to tighten the drill rod the same as the drill bit to avoid adding another variable into the mix. Another option, slightly less accurate, is to hold a piece of 1/8 drill rod in a collet with about an inch extended. Loosen the tailstock, tighten the chuck on the drill rod, snug the tailstock to the bed, then tighten the tailstock center clamp. Works like a charm, and it's fast too. You can use smaller, but keep your eyes open. 1/16 drill rod likes to flex. To verify nothing moved, release the collet, retract the ram, then try to gently push the drill rod back into the collet. If it hangs, something moved. Go back and do it all over again. It's not close enough - trust me, I tried to kid myself on this once, ended up with a lovely shaft with a pretty 270 degree crescent on the end rather than a concentric hole. As I already had a half an hours work in on the shaft I was rather ticked at myself. Don't be surprised to find that the drill chuck doesn't snug to the same center as the tailstock - a few thou variation can trash a small bit in a hurry. It also won't snug to the same center through its entire range. Like the three jaw, there is variation due to the tolerances of the manufacturing process. You will still see this on Albrecht drill chucks, just a lot less than on a $10 utility grade chuck. This is another reason much precision work is done with collets rather than chucks. Stan ------- Date: Thu, 01 Mar 2001 19:03:25 From: batwingsx~xxi-plus.net Subject: Re: indexing propeller hub At 09:40 PM 2/28/01 -0600, you wrote: >I did some indexing with the 3-jaw and 4-jaw mounted to the headstock at >one point. I did it >by using a bubble level straddling two of the jaws of the chuck. Nice thinking but the easy way to index with chuck is to set a stop between a jaw and bed. It's solid, stable, accurate and quick. The stop needs to be square on ends and the jaw should rest on it at outside corner, IOW, jaw needs to tilt downward to the stop. Regards, Hoyt ------- Date: Fri, 2 Mar 2001 11:34:07 -0800 From: Brian Pitt Subject: Re: Run Out: $64 question On Friday 02 March 2001 09:18, you wrote: > When measuring run out. Is it the displacement from the center > line or the total swing. That is if I put a indicator on a rod > in a chuck and it goes from +.001 past center to -.001 past center as > I rotate the chuck for a total dial movement of .002 is the run > out .001 or .002 it usually gets called out as TIR (total indicator reading) so the example would have a concentricity of .002 TIR Brian ------- Date: Tue, 06 Mar 2001 15:35:36 -0500 From: "Rich D." Subject: Re: how to find center of a circle bar stock david albert wrote: > Once again I hope this is not a stupid question, but how do you find > the exact center of a circle. For example, I want to drill a hole in > the exact center of 4" diameter aluminum bar stock. I tried a method > used in geometry class back in high school using a compass. > Essentially drawing 4 arcs and drawing a line from the intersection > of the arc points creating two perpindicular lines. I was off by > about 1mm. Is there an easier more accurate way? David, even if you were off a mm, it left you a nice small scribed box to visually center a center punch. Just a good as dead on. For "exact" work, you need a surface plate and surface gauge set to the radius, or the nearest sufficient equivalent. If you have a vertical mill, set the stock vertical and indicate the to center to get the quill dead on. With a lathe, set the stock to indicate zero runout and center drill. "Indicating" is with a DTI (dial test indicator), from previous discussions. Rich D. ------- Date: Tue, 06 Mar 2001 12:35:20 -0800 From: Alan Marconett KM6VV Subject: Re: how to find center of a circle bar stock David, use a center-finding head for a machinist's square. Looks like a 'V', with the blade of the square going through it. Scribe a line, rotate 1/3, scribe again, and you have the center where they cross. Rotate and scribe again, and your third line should ALSO intersect at the center! You NEED a square in your shop! ------- Date: Fri, 13 Apr 2001 13:27:35 EDT From: catboat15x~xxaol.com Subject: Re: dumb question"test bar" In a message dated 4/12/01, chad_gassawayx~xxhotmail.com writes: > what is the correct term for the bar you put between centers to align I think that "test bar" is the right name. I have never seen one in a catalog so I think most machine shops make their own. Get a good chunk of some material (Alum, Brass, Steel, whatever you may have around) Put it between centers and turn it with a ring close to the headstock, remove put the other end at the headstock and turn another ring the same size (use your graduated collars to make it the same.) Now you have your own test bar. This is assuming you have already used the pinched scale between centers to get the alignment close. John Meacham High Desert of California, Palmdale, Littlerock. ------- Date: Sat, 14 Apr 2001 20:25:46 -0700 From: "Nicholas Carter and Felice Luftschein" Subject: Re: Flycutting [TAIG MILL BUT TIP APPLIES TO OTHERS] From: > I am flycutting some 7075 aluminum and the overlap leaves about > a .001 ridge. I am taking passes at .001 in depth. Is there > any way to get rid of that ridge while cutting or is this a normal > occurance. You will have to excuse my ingorance I am a complete newbie > to this. Any help will be greatly appreciated. Thanks, Phil Warden This can be caused by the head being out of alignment to the y-axis. (assuming that you are taking passes along the x-axis and then moving over with the y). This has come to light recently with the new mills, as the dovetail plate which mounts the headstock to the mill slide isn't perfect and on large diameter cuts with a flycutter (or when tramming in the y-axis, which can mistakenly lead you to think the column is out of alignment - it usually isn't) Try shimming the dovetail plate to correct this. This can be checked by sweeping the y-axis with a dial indicator in the headstock. See our web pages http://www.casco.net/~felice ------- Date: Sun, 15 Apr 2001 03:39:27 -0000 From: airwardenx~xxhome.com Subject: Re: Flycutting Actually I am making my passes on the Y axis and transversing on the x axis. If I put a dial indicator in the spindle I get just a hair over .001 runout in a 2" diameter circle. ------- Date: Sun, 15 Apr 2001 02:54:23 -0500 (CDT) From: Tom Benedict Subject: Re: Flycutting On Sat, 14 Apr 2001, Nicholas Carter and Felice Luftschein wrote: > Try shimming the dovetail plate to correct this. This can be checked > by sweeping the y-axis with a dial indicator in the headstock. Thank you! So far my Y axis has been dead-on, but I've been dreading the day I find out it isn't, for fear I'd be shimming the whole column (NOT my idea of fun, OR of a good idea). Hadn't even occurred to me to shim the dovetail. DOH! Tom ------- Date: Sun, 13 May 2001 22:31:55 -0700 From: "Nicholas Carter and Felice Luftschein" Subject: Re: Re: Indicator point thred size? Paul R. Hvidston wrote:> Ballendo, > The replaceable tip thread size for most/if not all AGD style > indicators is 4-48. The other one is M2.5. You're right - I should remember to wait before posting with my faulty memory - I even bought a 4-48 die for just such a reason. See our web pages http://www.cartertools.com/nfhome.html ------- Date: Fri, 18 May 2001 13:09:00 -0500 (CDT) From: Tom Benedict Subject: Re: metrify inch by inch? On Fri, 18 May 2001, Nicholas Carter and Felice Luftschein wrote: > Not really, you can do one of two things: > 1) redraw any plans you have in a Cad program and change the units from > metric to english > 2) mount metric dial indicators on all axis. I heartily recommend #2. I don't even look at my handwheels any more (though I'm using English dial indicators.) I finally got my copy of "Building the Shay" from Amazon (after three months of biting my fingernails.) It's all in metric units. For the mill work that's not a problem since I'm using the CNC mill, for which units are a toggle. But for the lathe work, a metric set of dial indicators was exactly what I was planning to do. (And before anyone mentions that the Shay is likely outside the work envelope of the Taig, yeah, I know. I'm planning on scaling it down.) Tom ------- Date: Tue, 22 May 2001 14:38:31 -0400 From: "William Rutiser" Subject: Re: Manual Indication Here are a few things I have used... Get a straight round rod that is easy to chuck in the spindle. A drill blank or dowel pin that fits a collet would be a good choice. Prefer a nice round dimension that is easy to divide by two. Nip a strip of paper lightly between the rod and work. Try to establish a consistent feel as you withdraw the paper. You now know a relationship between the spindle axis, the work, and the leadscrew dials. You could use this at the ends of your vice jaw to set it parallel to the table travel. Or if you raise the spindle and move it toward the work by half the rod's radius plus the thickness of the paper, the axis will be aligned with the edge. The "sticky pin" is another old dodge that you may find useful. You need a common sewing pin and a small piece of something like modeling clay, Blue-tac, or a slow drying putty. Use the clay to stick the head of the pin onto the spindle, chuck, or tool, with the point generally on axis. Now run the spindle at a modest speed. The pin's point will traverse a small circle. Use a smooth piece of metal to push the point into the axis. This arrangement has some interesting physics. It is easier to do than to describe. When the pin is centered, you can use it to align the spindle with an edge or a scribe mark. A magnifier helps. Another edge finding trick... Stick a bit of paper to the work with oil or saliva. Now slowly advance a running cutter toward the paper. When the cutter touches the paper it grab it away. The cutter is now one paper thickness from the work. Cigarette paper is traditional for this. It's about 0.001 inches thick and consistent. Bill Rutiser ------- Date: Wed, 23 May 2001 01:18:22 -0000 From: ptolemyx~xxbellsouth.net Subject: Re: Manual Indication Thanks for all the suggestions -- this is a great group! The creative use of paper as a measuring device was something that I didn't think of. Some of the tricks I figured out are similar to some of the suggestions. (In case it's not obvious, ALL the follow steps are done with the milling machine turned OFF.) Here's how I find the center of a hollow cylinder: 1) I have some small biological specimen needles; these made of spring steel precisely 0.012" in diameter, and are extremely straight. 2) attach one of these to the mill head at a known distance from the center leaving about 5mm sticking down. 3) Lower the needle into the cylinder about 3/4 of the way. 4) Carefully crank the x-axis until the needle begins to touch the edge of the cylinder. At this point, the needle will bend slightly. This causes the lower part of the needle to deflect away from the wall of the cylinder and you can see a tiny gap open up. 5) Back off the x-axis until the needle just straightens out (the gap closes) -- conveniently this also takes up the backlash. 6) At this point I do the math and crank the needle to the center (taking into account needle diameter, position on the head, and cylinder diameter). 7) Repeat the process for the y-axis and then again for the x-axis. Now the needle is centered and the position of the head can be computed. Also -- this is probably a well-known trick -- I've discovered how to use shim brass foil to exactly position the cutter on top of a hollow. I cover the hollow with a little piece of brass foil , then carefully crank the (non-rotating!) head down. If the angle of the brass to the light is right, you can see it distort just when the head presses against it. You can then pull it out from under the head and account for its thickness. Maybe it's just beginner's enthusiasm, but I enjoy tinkering with the mill itself almost as much as I enjoy making things with it! Neil ------- Date: Wed, 23 May 2001 02:39:57 -0000 From: yahoox~xxaffiliated-products.com Subject: Re: Manual Indication To locate the tool to the work piece: A very fast and accurate way is to lower your spindle and it's tool off to the side of, but in the same Z plane, as your work piece. Using calipers measure from the shank to your work piece in X and then in Y. Then raise Z and move the table the amount you measured. For Z use the caliper to measure from the bottom of your tool to the top of your work piece. That's it. To find the center of a work piece, measure two opposite sides, and move your table to the center of the two measurments. This technique is as fast to do, as to say. It lets you keep the tool in the spindle. Is easy to verify by moving the table a known amount, past the work piece, and repeat the measurement. It can be accurate to 0.001", with a little practice. By the way, it is usually useful to machine a reference point on the work, as the first step. (Cut one of your corners or drill one of your holes). If this first cut can be roughly located, then it become the measuring point, rather than the tool, from which all the above mentioned measurements are made. Reasonable calipers can be had from MSC or Enco for under $20. The hardened measuring points of calipers are great to directly scribe onto the work piece. (I use a black marker first and then use the calipers to scratch the mark.) I had my calipers surgically attached to my right wrist. Buck ------- Date: Wed, 23 May 2001 23:58:22 -0000 From: ssmithx~xxserena.com Subject: Re: Manual Indication I use a home made continuity checker between the spindel and the part. With spindle stopped or running at a slow speed and just as the cutter rubs the part the continuity blinks or lights up. It use an LED mounted in a test probe with a 1K resister. I use a 9 volt battery with one end connected to the motor mount screw and clip the probe lead to the other terminal of the 9 volt battery. (Make sure the polarity is correct.) I put the probe point on the part. The 9 volt battery sits on the motor controller held between the power cord and the motor. Steve ------- Date: Fri, 15 Jun 2001 09:26:51 -0000 From: J.C.Beechx~xxshu.ac.uk Subject: Re: Dial indicator mount? --- In taigtoolsx~xxy..., "Eric" wrote: > I need some ideas for a dial indicator mount to indicate carriage > travel. I have a 2" dial indicator that I need to get set-up. Any > help or ideas would be greatly appreciated. Thanks, Eric Not so much help as advice for beginners going this route. I have always found with mechanical dial indicators I have owned that the scale is never linear, i.e you always get errors due to the rack and pinnion or just plain wear. Be very cautious of using a dial to take readings, they are really only intended for working to a zero point, i.e cutting to a shoulder etc. The digital gauges on the other hand have a very precise scale for the sensor and these are a good option for small measurements. I suppose the point I am getting at, is you don't need to use a long travel dial, for my use a steel rule and a pointer do for traversing the bed, the dial is used just to zero in for .001" accuracy. Anyone that can point me to cheap, accurate dial guages with 1" travel I would be eternally gratefull, but I am talking errors of less than .003 over the entire travel, and so far only digital has met the challenge. Joules ------- Date: Tue, 19 Jun 2001 09:33:01 -0700 From: "Dave Engels" Subject: RE: Graduation sensitivity of a machinist level to level a lathe From: Steve Leftwich [mailto:sleftwichx~xxwvutech.edu] >>From the information I have read for the leveling of a lathe, it says to use a "level at least 6" long that shows a distinct bubble movement when a .003" shim is placed under one end." In looking at buying a level, for example a Starrett 8" Machinist level Model #98-8, it lists the graduation sensitivity of .005"/ft. Is that adequate? Steve L. << Steve, a 0.003" shim under a 6 inch lever arm produces a 0.03 degree angle. This is a measure of the sensitivity of the level. A 0.005" per foot is 0.024 degrees, which sounds like it is better than requirement. Hope this helps Best, Dave ------- Date: Wed, 20 Jun 2001 00:30:19 +0000 From: Jon Elson Subject: Re: Graduation sensitivity of a machinist level to level a lathe > > graduation sensitivity of .005"/ft. Is that adequate? << It's better than nothing, but a more sensitive level is preferred. I have a Soviet-made master precision level that is graduated for .00075" / foot. The imperial-calibrated M.P.Levels are calibrated at .0005" / foot, or sometimes .0005" / 10 inches. There are import versions of this listed in most of the machine tool supplier catalogs, and they often have specials in the $89 range. Jon ------- From: Gordon Reithmeier Date: Tue Jul 10, 2001 4:25 pm Subject: Re: [sherline] Indicator/.0005 Joe Baker wrote: >>> This question is for anyone that cares to reply. How do I read an indicator that shows .0005 on the face and has 10 increment marks between 0 and 5. i do well with the mike and venier but I havent been able to figure thi little puppy out. Regards, Joe <<< Each increment = .0005(half thou), 10 increments = .005(5 thou.) Gordon, Toronto ------- Date: Tue, 21 Aug 2001 20:52:22 -0500 From: "Skip Evans" Subject: Centering on a 4 jaw chuck I learned a valuable lesson this evening. When centering a piece of square stock in a 4-jaw chuck using a dial indicator be sure to watch the revolution counter as well as the large needle. I eyeballed everything, then put the dial indidcator to it. All looked well as far as the large needle was concerned. I drilled the hole and realized I was off. What could have gone wrong? Well, I was exactly 1 revolution off. I guess I will have to remake the part. ------- [NOTE TO FILE: This subject was discussed in more detail and gathered in this site's file "Turning Tips Metal".] ------- Date: Thu, 23 Aug 2001 20:22:34 -0700 From: "Bob May" Subject: Re: Centering on a 4 jaw chuck The problem is that dial indicators all have a multiply turning needle. I use a test indicator always and that only goes around once and also allows for trailing (edge pushes up the ball while pulling on the instrument) edge measurements which will keep the measuring instrument from moving. Besides, dial test instruments are a lot more accurate than the run of the mill dial indicator. Bob May http://nav.to/bobmay ------- From: "Robert" Date: Fri Aug 17, 2001 8:56 pm Subject: Starrett Last Word Instructions I just purchased a Starrett Last Word Indicator, which I have been able to clamp to the Sherline Mill and I am now in the process of making a permanent fixture to give the Last Word something on the mill to attach to. However, there were no instructions with the Indicator and it has over six different accessories/attachments. I have been able to figure out a couple of them but I don't have a clue about how to use the others. I've searched the Starrett web site and searched the Internet but cannot find any instructions for the Last Word. Does anyone have instructions on how to use the attachemnts/accessories? I am mystified... TIA Robert ------- From: "Rich D." Date: Fri Aug 17, 2001 1:34 pm Subject: Re: [sherline] Starrett Last Word Instructions Robert, there are none. It's just common sense and a need to set it up with what's available. Look at what is there and see what can be used. It is a puzzle, as most machining problems are. You will learn, in time, to figure things out as the need arises. There are other accessories you can borrow from other sets. The Last Word has to be manually reversed with the little switch on the side of the body. The tip (stylus) is held in a serrated seat. To change its position, just force it to the stop and push more to jump it to the next position. RichD ------- From: "Bill Rutiser" Date: Sat Aug 18, 2001 10:25 am Subject: Re: [sherline] Starrett Last Word Instructions > I just purchased a Starrett Last Word Indicator, which I have been > able to clamp to the Sherline Mill and I am now in the process of > making a permanent fixture to give the Last Word something on the > mill to attach to. The lower screw holding the motor bracket to the spindle housing is a convenient place to attach an indicator mount. Bill Rutiser Gaithersburg, MD ------- From: ptolemy... Date: Sat Aug 18, 2001 11:58 am Subject: Re: Starrett Last Word Instructions I've found it handy to look through machining books like "Tabletop Machining" and "Machining Fundamentals", or magazines like "The Home Shop Machinist" or "Machinist's Workshop." You can find interesting examples of attaching and using DTI's (often Last Words). Some of the setups are novel and ingenious! -Neil ------- From: "Joe Baker" <855_1071...> Date: Sun Sep 2, 2001 4:58 pm Subject: Re: [sherline] Starrett Last Word Instructions The starrett catalog gives you a brief description of the uses for the last word indicator. They will mail you one if requested ------- Date: Mon, 27 Aug 2001 17:29:49 -0000 From: ptolemyx~xxbellsouth.net Subject: Interesting Rotary Table Accessory I made a simple but useful accessory for my rotary table today. The problem was, I needed to be able to center a part with an existing #61 drill hole on the rotary table so the hole was on center. I would normally do this by centering the table under the chuck, chucking up a #61 drill bit, and then using this to center the part. Unfortunately, other considerations in the setup made this method unwieldy, and I was making more than one part. So I did this: I turned a scrap piece of aluminum so that it fit snuggly into the center hole in the rotary table and flush with the surface. I drilled a #61 hole in this. Now I can center the part by passing a #61 drill bit down through the existing hole and into the hole in the aluminum part. The very slight amount of "play" is not an issue for my application. Neil ------- Date: Mon, 27 Aug 2001 13:01:15 -0700 From: Alan Marconett KM6VV Subject: Re: Interesting Rotary Table Accessory Hi Neil, just a thought, but why not scribe an accurate cross hair on your "plug", and use a "wiggler" center finder? If you are not familiar with it, the one I am referring to has a 1/4" shank that you mount in the spindle collet, and has a sharp needle point with a ball end that mounts into the shank's receiver end. The spindle is turned slowly, and the sharp needle point's wiggling is "trued" by lightly pressing it's point over with the end of a short piece of rod. Once trued this way, the needle point is "dead on", and you can move X & Y to align it to the cross hair. Drill bits tend to deflect, and a #61 could deflect considerably. OR- If the hole were bigger, a metal dowel pin might work a little better for you. Why not accurately turn the 3/8" - 24 (?) thread that the table takes on a 3/8" rod, and turn the other end down to 1/4", to fit a collet. Then you could "hang" the table from this rod, clamp it down, release the collet, and remove the rod. I am familiar with this task, I have a rotary table too. I think this could work! Another way would be to use a Test dial indicator (Last word) to "indicate" off the clamped work. HTH Alan KM6VV ------- Date: Mon, 27 Aug 2001 20:51:23 -0000 From: ptolemyx~xxbellsouth.net Subject: Re: Interesting Rotary Table Accessory Thanks, Alan. Those are good solutions for quickly centering the table. I like the rod and collet approach -- sounds like maybe I have a project for next Saturday :) In my current case, the spindle was being indicated on a different part of the part. The #61 hole was the center of the axis of rotation. My ad hoc accessory let me quickly move parts onto the setup in "assembly line" fashion. But you're right, the bit does deflect quite a lot and I have to use care not to stress it too much. I am definitely sacrificing some accuracy to setup speed. Neil ------- Date: Mon, 27 Aug 2001 15:11:51 -0700 From: "Craig Libuse" Subject: Re: Re: Interesting Rotary Table Accessory > I have been wondering why there is not a hole all of the way through > the center so that you can push things out from the rear. Joe feels that a hole all the way through the rotary table leads to trouble when chips fall through and get under the rotary table when it is moved around on the mill, leading to a non-flat setup. Some watchmakers have requested a through hole, so we have compromised by making the hole deeper but not quite all the way through. It is not a hardened part, so anyone can easily drill through your own if you have need for a through hole. If you do not need the threaded insert, the hole can be opened up as large as 1/2" without getting too near the inner race of the bearing. The threaded hole is used in the production process to locate the part for one of the manufacturings operations, so we need to keep it the size it now is unless we were to change the whole way we now make the table. Craig Libuse Sherline Products Inc. ------- Date: Thu, 30 Aug 2001 23:40:06 -0400 From: Thomas Gilmour Subject: Re: Interesting Rotary Table Accessory Neil & all, I had a project recently that required accurately centering the rotary table to the spindle. I made an adapter similar to what Alan proposed with a 3/8-24 thread and a hole bored through the center to accept a pin. I found that the accuracy wasn't as good as I wanted, possible due to the play in the thread. So what I ended up doing was turning a plug which fit snugly into the hole of the table above the threads. I bored a 1/4" center hole in this plug to snugly fit 1/4" drill rod. Clamping a short piece of drill rod in a collet allowed very accurate centering of the table. After clamping the table down the drill rod can be removed and replaced with a centering pin of any diameter needed which has a 1/4" end to fit the plug still in the table. Tom ------- Date: Sat, 15 Sep 2001 23:33:26 -0400 From: "Carol & Jerry Jankura" Subject: RE: Dial (test) indicator questions [IN USE ON ALUMINUM SHERLINE EQUIPMENT] 1. Magnetic indicators will NOT stick onto most sherline components, including the bases. They will stick onto the steel surfaces (ways). 2. Many of us have glued some ferrous sheet to the mounting board of the Sherline tool for the express purpose of holding magnetic bases. 3. Depending what you want to do, either can be the most useful. For example, you can mount dial indicators to allow you to accurately determine the position of the crossslides on the mill. You might use the Test Indicator to center the mill spindle on a locating hole in a workpiece. Which task you are most likely to perform determines which of the gauges you should buy first. Note that I said FIRST, because you'll eventually want to have both. Carol & Jerry Jankura Strongsville, Ohio ------- Date: Sun, 16 Sep 2001 20:12:50 -0500 From: "Bad Brad" Subject: Re: RE: Dial (test) indicator questions I have seen some people mount a steel plate onto the base board that the lathe and mill are mounted to. If you own a sherline lathe with a brass way, the magnetic indicator base will not work either. I have found when working on centering stock, in what ever chuck or face plate you are using, remove the magnetic portion of the test indicator base and hold it in the tool holder on the sadle. This is a very rigid set-up. An extra tool holder either made up or purchased will speed up set time up as well. For centering stock in a four jaw I use a Starret Last Word; they are small, mount in a tool post perfectly and can be purchased used with most of their attachments, cheaply ($10-$35). Forrest ------- Date: Wed, 07 Nov 2001 07:38:33 +0000 From: Jon Elson Subject: Re: dial vernier caliper question Steven Harris wrote: > My dad had me make some small part for him. I made them and mailed them > off. He e-mailed me back saying that they did not fit because they were > .001" too big. I was confused because they were exactly the size he > specified (I had triple checked each part. You have to make quality > parts for dad.) After some discussion back and forth we figured it had > to be my measuring device ( all of 7 identical parts were exactly .001" > too big). So I took a look at my trusty dial vernier caliper. I found > when the jaws were closed I could see light coming through them in the > area I usually use to measure. Checked the gap and it was .001". So do > these things wear out? I take good care of my measuring tools always > storing them with the jaws open, making sure that they are clean, > checking the zero before each use and storing them safely. Or is this > something that was present when I purchased them 12 years ago? I'm > thinking that it will be something I check on my next purchase. Dial calipers aren't all that accurate. It is also fairly easy to ding the measuring surfaces or the tips of the OD jaws. If you see light evenly along the length of the jaws, there is a ding somewhere. If there is light only at one end, then the jaws aren't parallel. Since you zero'ed the caliper and then made parts .001" oversize, that pretty much sums up the fact you have a ding somewhere. A .001" raised spot from a sharp object scraping the jaws is pretty hard to find. Any time I make a precise measurement, I wipe the jaws with my fingers, from the middle outward each direction, to remove all tiny grit particles. Cloths and paper towels leave dust particles, so clean hands seem to be the only thing that works. A fine india stone can be used to remove the tiny raised mark if careful wiping doesn't fix it. If the problem is right at the tip of the jaws, you can file the jaws down a little or use the side of a bench stone. Obviously, do this very carefully, and then even up the two jaws. For more precise measurements, you need a micrometer, they are much more accurate than a caliper. Jon ------- Date: Wed, 7 Nov 2001 02:54:30 -0500 From: "Darryl Urcheck" Subject: Re: dial vernier caliper question I have found it's useful to have a friend periodically double check a part with his micrometer, using it as my gage, so to speak. Also, I use Vernier calipers for rough measurements, but .0001 micrometers for finer work. Friends criticize me for being too precise, but hey, I'm not in a hurry: measure twice, cut once. This is especially true on some engine work. We have come a long way from the days when a 1/64 steel rule was used for engine work. Darryl ------- Date: Sat, 08 Dec 2001 12:55:30 -0500 From: ron ginger Subject: Re: DRO I personally dont like the Sherline DRO- it is really a turns counter on the lead screw, it does not sense the actual table movement. It does have software compensation for backlash, but you need to measure the backlash accurately or else the readings wont be accurate. And if the backlash varies along the screw (and Im sure it will with wear ) then it wont be accurate. I suggest you buy 2 digital calipers, which can be bought for as little as $40-50 on various sales. Make a couple brackets to attach them to the tables. You then have a direct measuring device, most have zero reset and will do metric to inch conversion. And if you make the bracket well the caliper can be removed quickly and used as a caliper. The only drawback to this is that the two readouts won't be beside each other on a nice display. But you save at least $200 and get a device that is a real DRO, not a wheel turns counter. Sorry to be negative about a Sherline product, but IMHO this one could be better. ron ginger ------- Date: Sat, 08 Dec 2001 18:33:12 -0000 From: "n2562001" Subject: Re: DRO Ron, I can`t comment on the Sherline DRO since I have not used one other than play with them at show`s. However a while back I did clamp a Mitutoyo 6" Digital caliper to my Sherline mill and try what you have suggested. It seemed to work Ok until after about five hours of operation when it died. When I opened the unit up it had several damaged circuit board connections that appeared to caused by machine vibration. Since then I have talked to two other people who have tried this with the same short life results on small mills. I have a extra Mitutoyo DRO Quill travel unit I may try one of these days and see if I have better luck. Just my experience; thought it may be of interest. Have Fun Jerry Kieffer ------- Date: Sat, 8 Dec 2001 12:20:04 -0800 From: "Yasmiin Davis" Subject: RE: Re: DRO Has anyone tried this? The Bridgeport spindle down travel measuring devices are cheap and made for this. It would seem that they should work well and they even come with the mounting brackets. Yasmiin ------- Date: Sun, 09 Dec 2001 17:40:01 -0500 From: ron ginger Subject: Re: DRO I have had a caliper on my Bridgeport quill feed for a couple years with no trouble. Im sure it gets as much vibration as any Sherline size machine. Wholesale Tool (stores in several cities and on the web) sells what appears to be the same mechanisn as a caliper, just without the measuring arms on the ends, and with brackets to mount is on a mill. They offer them is several lengths, up to about 18" as I recall. It is important with any DRO to be sure the table travel does not bind or jam on the caliper. I have a Mitutoyo DRO on my Clausing mill, and the installation instructions were very clear on the importance of alignment. Maybe the early caliper failure came from a misalignment? ron ginger ------- Date: Sat, 15 Dec 2001 19:37:58 -0500 From: ron ginger Subject: DROs and Calipers I have had a caliper attached to my Bridgeport Z axis for several years with no trouble. This is an actual caliper which I cut down to fit. There are also similar packages sold with brackets to fit a mill. All 'real' DROs have an electonics package in the reader head. I have a Mitutoyo low-end unit on my clausing mill and it has exactly the same mechanism as the caliper, with read heads attached to the table. It has been inuse for 5 or 6 years with no trouble. So, I see no reason a caliper wont work just fine as a DRO on a Sherline. I suspect the warning against their use is by 'armchair experts' that are speculating on things that could happen, not real experience. On, The Sherline DRO has an encoder in the reader unit, which is also electronics, so if vibration kills electronics how do they keep working? ron ------- Date: Mon, 17 Dec 2001 09:27:56 -0800 From: "Craig Libuse" Subject: Re: DROs and Calipers >So, I see no reason a caliper won't work just fine as a DRO on a Sherline Ron, our experience was based on trying one and having it go bad. Jerry Keiffer had the same thing happen. Perhaps we both got bad units and gave up too early, but the experience was not theoretical. Maybe the larger mass of the Bridgeport lessens the effect of vibration on the caliper. The Sherline encoder is a simple optical unit that senses the position of teeth on a star gear in the handwheel unit. The circuit boards are in the control box, which is a separate unit. Some people have mounted their control boxes on top of the speed control with Velcro or double/stick tape as a convenient place to read the output and keep the cables out of the way, and I haven't heard of a failure yet. Could be the tape insulates some of the vibration or maybe our larger circuit boards and chips are a bit more sturdy than the tiny ones used in the calipers. Craig Libuse Sherline Products ------- Date: Mon, 17 Dec 2001 19:29:51 -0000 From: "terry6453" Subject: Re: DROs and Calipers I turned my nice new mill on and it does not seem to vibrate nearly enough to damage normal electronic components (I am a reliability engineer). Electronic circuit boards survive in car engines, wrist watches, missiles ... with no special problems. The mill "should not" be any problem at all. My first thought is that the caliper was just "a bad one". However, it appears Craig as seen a bad "two" now, which is odd. If the calipers really are being killed by the mill environment, there are some special weak spots to suspect. 1. Battery connections in calipers are a bit none standard and tend to use the stainless steel body of the caliper that may have contact problems. 2. The LCD screen connections may be susceptible to vibration. This type of connection is well understood but if the screen design in the calipers is unusual someone may have done something creative and messed it up. 3. I assume they use a magnetic head and strip to determine the position in these things. Vibration may confuse the electronics if the head vibrates over a mark and seeds high speed signals back to the electronics. This may lock up the electronics but removing the batteries and reinstalling them should clear the problem if simply turning it off and back on does not. This could be a real big problem if vibration causes the reading to drift as the caliper gets false movement signals. 4. The magnetic pickup could be failing if it was not made well. I assume it is a Hall sensor, which should be indestructible. If it is a coil of wire like a tape recording head it may have a weakness. 5. Static electricity could be zapping the electronics. This is a very big possibility. 6. The buttons for the controls could be having a problem with vibration especially if their design is sort of odd. 7. The batteries ran down ;-) I would think removing and replacing the batteries should restore the caliper to life. If both failed calipers were the same brand and type, they may have some common defect that does not affect other types. I looked at my Starrett 723 and a few digitals I found at work and they look pretty tough. I don't feel like taking apart the Starrett since it is not broken (yet :-)) but maybe I'll pick up a cheap caliper and play with this. I have a nice wide-band G-sensing vibration probe and FFT scope I'll hook to the mill tonight to see what the vibration looks like. I doubt if it will show anything but it sounds fun to do and will help me justify those expensive toys too :-)) If you still have the broken calipers, try removing and replacing the batteries and checking the batteries to be sure they are good. If you can tell us what went wrong with them (dead, display gone nuts, frozen, etc.) that may provide clues too. Of course, using a caliper is only one of many options, but it is attractive in some high precision or inexpensive applications (especially if one already has the caliper). Mounting the darn thing is another challenge... Cheers, Terry ------- Date: Mon, 17 Dec 2001 13:57:06 -0600 From: "Bad Brad" Subject: DROs and Calipers The main problem with the hand-held calipers is the fragile pickup for position. Wheather the position pickup is magnetic or optical the amount of vibration to knock these parts out of alignment is not much. I can tell you (Ron) that the people you refer to as "armchair" people are far from it, their experiences are learned first hand and not made up. I would not let any of the stuff written in these (Sherline or Taig) news groups stop anyone from trying things for themselves. Usually the words can't or shouldn't are invitations for doing it anyway. Forrest ------- Date: Tue, 18 Dec 2001 03:13:06 -0000 From: "terry6453" Subject: Re: vibration - DROs and Calipers I checked out the mechanical resonances and vibration of my Sherline 5400 mill to see if there was anything there that may hurt an electronic caliper. I hooked up a Tek3012 Scope with FFT and a Measurement Specialists 0-20kHz accelerometer to my Sherline mill. A just taped the sensor to the back of the mill vise as shown. http://hot-streamer.com/temp/Sherline/Pc170002.jpg http://hot-streamer.com/temp/Sherline/Pc170003.jpg At first the electrical noise was messing with the tiny sensor's signal. The plastic case that houses the mill's electronics does not shield the electrical switching noise from the electronics well. A transistor radio picks up the noise nearby but it goes down fast as the radio is moved a few feet away. Practically, this noise is not of much of a concern but it could be a factor to the damage reported to digital calipers. One may want to insure that the caliper and the metal frame of the mill are electrically connected (grounded). The noise is mostly radiated like an antenna, so a simple grounded foil shield reduced it enough to get a good scope reading: http://hot-streamer.com/temp/Sherline/Pc170001.jpg A metal shell around the electronics and perhaps a little bypassing would stop this noise, but it probably does not matter unless you are trying to do something strange like this. So I turned the mill speed up and got the following: http://hot-streamer.com/temp/Sherline/Tek00000.gif The yellow shows the raw vibration from the sensor. 7.9 mV is equivalent to 1 G so we have about 0.89 Grms of vibration. That is very small and will not hurt anything. The red line is pretty neat. It is a graph of the frequencies of vibration. It shows that the vibration is almost entirely made up of 8 frequencies. The left side of the graph is 0Hz with every major vertical line representing 250Hz. So reading them off, it looks like there are resonances at: 120, 240, 350, 400, 475 and then another set at: 1160, 1200, 1230 Hz. I will leave in to mechanical types to decide what causes these but "I" would guess that the low frequencies are from the longer metal parts and the high frequencies are from the smaller parts (or dimensions) like the vise. I wonder if the surfaces were never parallel, like in a stealth fighter, if that would reduces these? Smooth rounded surfaces might also like in those big Bridgeport mills (but even they have big square tables...). I suppose by knowing the speed of sound in aluminum and the dimensions of the mill's features one could find where these resonances come from. Stuff like that makes my brain hurt so I'll pass :-)) Even the highest resonance here is only 0.34 G so nothing is going to hurt a caliper. With the foil, I could not run the mill in an actual situation. However, those vibrations are not inherent in the mill but in any vibrating object. Thus, if those vibrations break a caliper, so will mounting it to all kinds of other things. You just need a better caliper... So I hope I didn't loose everyone :-)) but the bottom line is that the mill does not vibrate oddly or do anything it is not supposed to do. There is nothing here that would hurt a caliper. If one mills things that knock the mill around and cause a lot of pounding, that may be different. However, I would think that is a caliper problem not a mill problem. The electrical noise "could" be a factor but simply grounding the metal frame of the caliper would stop that from being a concern (It may also cure any static electricity problems). I doubt it would hurt anyway but the electrical noise and spikes are pretty strong. If I have not bored you to death already :-)) The accelerometer uses a micro machined lever arm. It uses capacitance to sense the tiny arm's position to determine G force. If you hold it upright it measures 1 G, if you turn it upside down, it measures -1 G. Lots of high tech there and it is really cool! FFT graphs like the above can be used to inspect aircraft and other high importance assemblies. If some major part is loose, the graph will show it as the peaks moving around or being missing. Good parts should all have exactly the same graphs. Some people can hear resonances like the above and pick them out by ear. I imagine you need perfect pitch or something to be really accurate but I guess we have all heard strange whines in cars and such which is the same thing. Some people can listen to machines and determine that something is wrong when others can't. They are simply trained to hear the "right" noise. Cheers, Terry ------- Date: Tue, 18 Dec 2001 08:28:17 -0800 From: Mark Fraser Subject: Cheap calipers Having owned 4 of these for some years, my armchair opinion points toward the battery contacts. If vibration will affect anything, it might just cause enough abrasion of the crappy plating to make contact somewhat intermittent. I've had some "failures" in normal use (or non-use or misuse) that miraculously fixed themselves after I cleaned up the batteries and contacts. The technology is CAPACITIVE, not magnetic. Little rectangles are etched into copper clad FRP (printed circuit board) with dimensions and spacing to allow similarly dimensioned sensor electrodes in the caliper head to detect transitions up / down. Spacing is sorta like vernier scales - small differences between spar and sensors. All in the very old (1990) Circuit Cellar INK article. Someone who became a legend in RCM once published an article on making very long spars for cheap calipers, for use as DRO for larger machines. Previously mentioned, but worth another mention, is the Mitutoyo spar, which most likely uses their digital caliper technology that has been so widely copied in the cheapies.... /mark ------- Date: Tue, 18 Dec 2001 20:32:59 -0500 From: ron ginger Subject: Re: DRO and calipers Thanks Terry for the detailed analysis. One of the things I love about these e-groups is no matter what the topic someone with real serious expertise always pops up when you need it. All of the calipers Ive seen use a capacitive effect for the position sensor. The fixed 'scale' is a piece of PC board with a pattern of rectangular copper areas on it. The copper pads are about 0.2" x 0.4" The read head is an IC chip mounted to slide a fixed distance off the copper pads. The copper pads are covered with a plastic material that provides insulation and protection from dirt, etc. An article in an early PROJECTS IN METAL described this in detail, including the description of a very long scale the author made by CNC engraving a piece of PC board stock. I would guess the main reason one of these would fail would be the simple rubbing of the read head over the scale. On a mill they would likely get more 'mileage' than as a caliper. I've had my Mitutoyo DRO with this mechanism in use for several years now with no indication of trouble. In today's mail I received a flyer from Wholesale Tool with an ad for their line of "Machine scales' These are clearly the mechanism of a caliper, but just a plain metal scale, no hooks on its ends. They offer a model with the LCD display both horizontal and vertical, and in sizes from 4" to 40" long. The 4" long unit is US$44.50. The 12" is $76. So for just under $120 you could have 2 scales, made for use on machine tools, with a resolution of .0005" and a repeatability of .0005", with instant inch to mm conversion and zero reset. And, if you want a display box they offer a 3 axis display box with 3 cables each 6ft long and large red LEDs for display for US$259. They have a single axis with large fromat disply and a 37" scale for $105. WT has a web site at http://wttool.com Someone asked about RPM- no, these calipers will not measure RPM, just the position of the table. ron ginger ------- Date: Tue, 25 Dec 2001 03:40:55 -0000 From: "terry6453" Subject: Re: DRO and calipers Hi All, I got the digital machine scale from Wholesale Tool today. Unlike hand calipers, these things are built really big and tough. Lots of stainless steel and rugged! They are definitely made for hard use. They can be mounted in all kinds of ways. I tried one way but it was too loose. I ended up just using double-sided foam tape to stick it on the side of the headstock. That actually works perfectly fine although that sounds "too" simple :-) I coated the mating surfaces with a thin coat of oil and rubbed it off well so the tape would be easily removable (I didn't want to drill any holes in the mill). I did make a little plastic spacer and a quick (needs improvement :-)) weight for the slide. The 12-inch scale cut down may fit nicer but it costs almost twice as much. I could easily get 0.5 mil repeatability and its readout matches the hand wheels and the other Starrett gages. So it works fine and it is easy and smooth to use. I was having a little trouble getting really accurate Z dimensions before but now it's child's play! There is a picture at: http://hot-streamer.com/temp/Sherline/Pc240007.jpg The instructions list a wide variety of things to do if it stops working including taking it apart and cleaning the switches and such. They thought of all the same things we did ;-) However, I don't think this will be breaking anytime soon. For a nice $50+ digital readout it is prefect and I really like it. I think they are too big for the X and Y table movement. However, I have just been using digital calipers against the metal edges there which works fine. I can also verify that the graduated hand wheel marks are very accurate so using them is no problem either unless you think in absolute dimensions and can't count turns like me ;-)) I also got that fancy turntable today. Definitely worth the $200+. It is solid steel and works perfectly! It will be perfect for wheels, rotors and such :-)) Time now to go play... Cheers, Terry ------- Date: Sun, 6 Jan 2002 00:07:17 -0500 From: "Jeff Bissonnette" Subject: New member/comments on DRO Hello all! I'm a new member to this list as of tonight, though I've known about its existance for some time. I currently own both a Sherline model 4000 lathe and model 5000 mill (both pre-zero adjust handwheel, and the mill has an AC motor), as well as a bunch of Sherline's accessories. I've looked back through the archives and found a lot of informative and interesting posts. I read through several posts regarding DRO's and using digital calipers as a means of measuring axis movement. I have another suggestion that I've used and it works very well for me. For the Y-axis of my mill, I made a bracket out of aluminum that holds a Mitutoyo 2" dial indicator, which is bolted to the column base with the tip of the indicator running on the back surface of the milling table. Before some of the diehard career tool makers and machinists out there balk at this, let me say this. IT WORKS!! Thanks in part to the excellent manufacture of the Sherline mill! On my mill, running the table from one end of the X-axis travel to the other produces NO noticeable change in the indicator reading. Not sure if all other Sherline mills out there are the same, but mine is great... Anyway, it was cheap and easy to make, I purchased a 3/8" reamer just to make such brackets (most dial indicators have a 3/8" stem), which makes it even quicker. Though with my existing 1/4" max. cap. drill chuck I had to use my 3-Jaw lathe chuck to hold the reamer!! Anyway, the Y-axis was easy because 2" of travel is more than enough for what I need to do with it, hence the 2" DTI. For the X-axis, I came up with a similar solution as those suggesting using a digital caliper but I instead substituted Mitutoyo's Bridgeport Z-axis DRO. I used laser cut steel brackets bolted to the mill table to hold the unit, and attached it to the mill saddle via aluminum and steel parts. It too works very well, "great" even though the amount of travel is limited to about 5" while it is installed on the mill. Again, for the small parts I machine that is not a problem... I've found it to be dead accurate, and I can often "hit" dimensions using it to +/-0.0005" if not "dead on". The only problem I have with it is due in part to how I've tied it into the mill saddle. I've made it removeable, which creates about 0.001"-0.002" of "play". Not a serious problem; I just have to remember to use the same "trick" used when counting hand wheels, that is move in the same direction and if you have to reverse direction go farther than you needed to go and come back. If I would screw the bracket on the saddle and mounting bar together, I'm sure that this would eliminate any problems with this "play". In either case (indicator and/or Mitutoyo DRO) I have experienced NO problems with vibration, or either measuring device "failing" under use. I've been using my set-up for about 2 years now in this configuration... For your viewing pleasure I will post photos to the "files" section showing my set-up. I'm glad to be a part of this group and look forward to the plethora of very useful information I will get from you guys. Best Regards, Jeff B -------- Date: Sun, 06 Jan 2002 15:09:17 -0500 From: ron ginger Subject: Re: DRO- Dial Indicator Jeff Bissonnette wrote about using a 2" travel Dial Indicator on his mill. A friend of mine does this, but in a somewhat simpler fashion. He mounted his mill and lathe on a table top covered in sheet metal- a fairly thick sheet, and painted it nicely. He uses a magnetic base indicator stand which he can plop down anywhere around the mill or lathe as needed for a particular setup. Its fast and easy to move and adjust, and those magnets are plenty strong to resist moving. He actually has 2 or 3 indicators on stands so he can use a couple at a time. Also works very well on the back side of the lathe to measure the cross slide travel, or alongside the table for length of turned objects. You can often place them into positions that would never be possible with a fixed bracket, because you drop it down after the setup is made. I cut the case of an old PC apart to use its side pannels for this, they are well painetd and plenty stiff. You do need to be careful that you align the indicator carefully for the direction of travel so you get an accurate measurement, and note dials are only good for about 1% accuracy over the full travel range. But $25 will get a 2" imported indicator form any of the big suppliers, and the bases are always on sale for $10-20. ron ginger ------- Date: Sun, 6 Jan 2002 14:04:38 -0500 From: "Jeff Bissonnette" Subject: Re: Re: DRO- Dial Indicator "A friend of mine does this, but in a somewhat simpler fashion. He mounted his mill and lathe on a table top covered in sheet metal- a fairly thick sheet, and painted it nicely. He uses a magnetic base indicator stand which he can plop down anywhere around the mill or lathe as needed for a particular setup. Its fast and easy to move and adjust, and those magnets are plenty strong to resist moving." Ron, I've done this for my Sherline lathe... Only I use small squares of 1/16" thick sheet steel screwed to my workbench. It works well with the 1" indicators I use so long as you aren't rigorously cranking on any handwheels. I use a small machinist square to align the indicator stem to the cross slide table. Close enough that when you work out the "cosine" error for the few thou it may be off it results in an error of nearly zero for 1-2" of travel of the indicator used. I'll throw a photo in the file folder I created in the "files" section showing my set-up. Most of the time I only use it for Z-axis travel (along the bed). BTW, I went to www.discountcampus.com. GREAT site!!! I found a better solution to the DRO set-up I have. They sell Mitutoyo DRO's and they have longer measuring ranges... I may have to pick one up to retrofit my current set-up!! I'd be able to use the full X-axis range of movement of my machine that way... Jeff ------- From: CaptonZap... Date: Sat Jan 19, 2002 10:26 pm Subject: Re: [atlas_craftsman] Edge finders 1/19/2002, skip_evansx~xxh... writes: << I have two edge finders, one with a straight tip and the other a pointed tip. How is the finder with the pointed tip used? >> After you have prick punched the center of a desired hole, you CAREFULLY put the tip into the punch mark, and center your workpiece. Most Bridgeports and clones have a small amount of down quill feed travel that is spring loaded. The spring doesn't put enough pressure on the point of the center finder to bind it in the hole. With a drill press, you will have to feel your down, and hold a slight amount of pressure while you center the workpiece. A drop of oil would ease your mind. 8) CZ ------- From: Thomas Gilmour Date: Thu Jan 24, 2002 3:11 pm Subject: Re: [sherline] good dial indicator / centering device. Ifbige28673 wrote: > I want a good method for locating the center of round stock for > drilling operations.I was looking at a centering indicator but there > is not going to be enough room for it to fit between the spindle and > milling table.This would in my opinion be the best measuring tool > since it will "sweep" both the ID and OD of round stock and with the > addition of a spindle lock you could square up flat stock along one edge > also.Any ideas or solutions?I have ordered the 6200 DRO outfit from DPP. you're not looking for extremely precise centering you can use a wiggler mounted in the spindle to line up with scribed marks on the part. I've also used my dial test indicator to sweep internal holes and the outer edge of small diameter round stock. Rather tedious but it works, however with the standard indicator point I don't think you could sweep anything larger than .500" or .750". Tom ------- From: "terry6453" Date: Thu Jan 24, 2002 7:43 pm Subject: Re: good dial indicator / centering device. I am not sure what the size of your round stock is but here are three tools that should be of interest. The first is the "edge finder". Sort of hard to explain it but when you see it working you will get the idea right away. It has a 0.2000 inch sliding tip that will slip out of place when it just touches a straight edge: http://hot-streamer.com/temp/Sherline/EdgeFinder.jpg The shaft is 3/8 inch so it fits in the 3/8 inch adapter perfectly. When it "finds" the edge, the centerline is exactly 0.100 inches away. This may be of limited use on round stock since it likes flat edges. Starrett is the usual choice (MSC# 86425246) at a pleasant $17.50. I use it all the time but for flat edges. Probably good to 0.00025 inch. If you have a mark or point you want to drill without any other dimensions to go from, the "Wiggler" is your tool: http://hot-streamer.com/temp/Sherline/Wiggler.jpg You will have to "see" this one in action to get how it works too. You spin it and touch the tip with something and it swivels right to a perfectly placed point. Then its tip will be a perfect point to line up with the mark on the work (magnifying glass). Starrett 828 MSC# 86425295 at $12.40. Almost a must have... Accuracy depends on your eyes 8-) A few mil for me... The tip could be a little shorter, so a friend with a lathe to chop it may be an option. I hear there are other "tricks" for using this tool on round stuff but I don't know them. I think what you really want is the "Last Word 711" gauge by Starrett. Many many uses! It is a fine dial gauge made for touching perpendicular surfaces. It is marked in 0.0005 but you could actually go better: http://hot-streamer.com/temp/Sherline/LastWord.jpg http://hot-streamer.com/temp/Sherline/LastWord2.jpg With this, you can set it to the outer (or inner, it has a switch for both) surface and "play" with the X-Y to get a round piece in perfect alignment (0.00025). You can turn the quill to see how far out of round the work is from the centerline and make adjustments directly. I set it up and tried it and with some tiny practice it is very easy. Cost you more it will!! $:o)) Starrett 711 MSC# 86424314 at $115.00. There are some cheaper types but get the Starrett ;-) It can also be clamped in a vise with an included adapter for other alignment work. It has a 1/8 inch shaft that you can easily stick in a drill chuck or 1/8 collet. The mounting could probably be modified if needed. I use it to align just about everything with the mill and vises. Note that your "round" stock should really be "lathe machined" round. If it is a few thousandths off from round, then you will have to "fiddle with it" :-)) Also, you may need a thin film of oil on the part for these contact gauges to get a "smooth" reading. All three of these are long standing "must haves" of the machining industry and they work very well. Every machinist knows them well and they are just assumed... Aside from gauge blocks (for quickly setting up square stuff, WOW, I use them a LOT!!), you really don't need anything else. Not sure the square blocks will help with round stuff... Cheers, Terry - Gosh! Sometimes I sound like I know what I am doing :-))) ------- From: "Al Lenz" Date: Thu Jan 24, 2002 10:45 pm Subject: RE: [sherline] Re: good dial indicator / centering device. Terry, good info. Here is my Tip of the day: Using double sided tape and a refrigerator magnet, stick a pocket mirror to the mill column. You can see the indicator dial on the backside without getting a crick in your neck! Al Lenz ------- Date: Fri, 25 Jan 2002 22:37:03 -0000 From: "Ted Walls" Subject: Re: good dial indicator / centering device. Are you cross drilling or end drilling? For end drilling I'm not too sure as to what size bar you will be using, but a dodge I have used in the past with end centering round or square bars is to make ,or have made a bar with a 20 degree cone machined in one end the other end say 1/4 for a collet. Mount the bar perpendicular in the vice and, with the vice screws or clamps loose, bring the spindle down so that the end of the bar enters the cone. Tighten the clamps and the bar is now central to the spindle bore ready for drilling. For cross hole drilling, an accurate and easy to make and use tool can be made by machining a piece of round stock about 3/8 in diameter and say 3 or 4 in long to half its diameter for about 1 1/2 in at one end and turned down to suit a collet at the other. Make a 'Y' shaped piece of something like 16SWG material (steel brass or aluminium) with about 1 in long legs with a small hole say 1/16 or 3/32 in the middle of the 'Y' make the same size hole on centre and about 1/4 in. from the end of the bar with the flat on it. Assemble the 'Y' piece to the bar so the 'Y' is upside down and put a good fitting pin thro both the 'Y' and the bar. You now need to "calibrate" the tool by centering a bar below the spindle using the tool. It is easiest to do this with the with the bar along the table West to East so to speak. You can easily see both sides of the too this way. Clamp the bar to the table and bring the tool down so that the 2 legs of the 'Y straddle the bar using a fine felt tip or pencil mark a line central to the bar and onto the top leg of the 'Y'. Now raise the tool clear off of the bar, rotate it thro 180 degrees and lower to straddle the bar again. Note the misalignment of the lines. Move the table half the misalignment and mark the top leg of the 'Y' only. Clear the bar rotate and repeat again. If all has gone well the second line you marked will line up with the line on the bar. If not repeat until it does. When the lines align both ways the tool is "calibrated". Permanently mark the lines with a scriber. From now on all you need to do, to centre a bar, is clamp it to the bed or hold in a vice, put the tool in the spindle, bring it down to straddle the bar and move the bar using the handwheels until the lines on the 'Y' and the bar align. The centre of the spindle is now central to the bar. Once made the speed and ease with which a wide range (size) of bars can be centralised makes the effort of making the tool well worth while. If you can't understand my ramblings contact me off list and I'll send you a couple of simple sketches. ------- Date: Tue, 05 Mar 2002 16:03:53 -0800 From: Ben Bennett Subject: telescoping gages I bought some telescoping gages from HF (made in China) and it drives me nuts trying to use them. Whenever I try to measure an inside diameter with them it always comes up short. The way I do it is, I press the probes together, tighten the handle (for want of a better name), stick it in the hole, loosen the handle (letting the probes pop out against the inside of the hole) and tightening the handle. Then I mike it. What am I doing wrong? Is it me or the gages? Ben Bennett ------- Date: Wed, 06 Mar 2002 11:02:01 -0700 From: "Ron Shaw" Subject: Re:Telescoping gages I have a set of those gages, and they drive me nuts, too. They are better than nothing, but not by much. The anvils stick closed and won't release when you loosen the screw, etc, etc. Take them apart, as I did, and you can see why. There is NO finish work on the parts whatsoever. Even after cleaning up the ragged edges and whatnot and reassembling, they are not a whole lot better. They are made cheap to sell cheap, but as far as being any kind of a precision measuring instrument, forget it. Ron Shaw ------- Date: Tue, 5 Mar 2002 22:24:17 -0600 From: "jerdal" Subject: Re: telescoping gages Way I have heard is put them in, vertical, cock handle up a bit (hush you Brits, that's not what I meant) off straight, tighten just to hold, then one sweep down with the handle past straight, pull out, snug up and measure. Your problem is likely not the gages, if they don't have a friction problem, but rather with the cut. A rough cut is usually a couple tenths of mm (few thous) over what it measures due to the ridges in the bore. The rough bits smash down easily, and bore seems to have expanded. Jerry ------- Date: Wed, 6 Mar 2002 01:07:42 EST From: catboat15x~xxaol.com Subject: Re: telescoping gages In a message dated 3/5/2002, greyhawk200x~xxatt.net writes: > The way I do it is, I press the probes together, tighten the handle > (for want of a better name), stick it in the hole, loosen the handle > (letting the probes pop out against the inside of the hole) Two possible reasons. Are the anvil and spindle of your mike pushing the probes together? Are you sure you are measuring on the full diameter of the hole and not on a chord? How far off are you and is it consistant? Oh, make that three reasons possible defect in gauge when tighting the handle it may shift the probes a bit. Most of our amateur tools require getting a feel for measuring to high precision. That is the reason a mike is better for outside measuring than a dial caliper as a caliper does not have the feel and the measuring jaws deflect differently depending on how hard you close the jaws on the work. John Meacham California High Desert 12 inch Atlas, Minimill, rusty file ------- Date: Wed, 06 Mar 2002 04:23:46 -0000 From: "jdmichael2001" Subject: Re: telescoping gages Ben, the technique I was taught was to insert the gage in the bore at a diagonal, then loosen it so the arms telescope out to the I.D. Snug up the handle, but not too tight, then pivot the gage so the arms are compressed through the smallest effective diameter ONLY ONCE. Withdraw the gage and mike it. Again, pivot the the arms through the mike faces to get the same feel as when you pivoted in the bore. It will help a lot to have a practice bore you know the size of acquire the right feel. It takes a while to learn to trust the once through the bore and to feel the same drag in the mike, but we used to measure to tenths with telescoping gages for shrink fits. Jan ------- Date: Wed, 06 Mar 2002 06:32:10 +0000 From: Jon Elson Subject: Re: telescoping gages > tightening the handle. Then I mike it. What am I doing wrong? Is > it me or the gages? These things are pretty hard to use. When you release the clamp, you have to wiggle the handle gently to allow the spring pressure to force the feeler tips to find the true diameter. On the larger gages, you need to use hand pressure to offset the weight of the gage so that it is at true center. After clamping the tips, I then move the handle to see if the tips are truly on center, of if there is some free play. If there is free play, the tips are not at the true diameter. So, I try again. Some of these gages may not be machined well, and the tips may be drawn in when you tighten the handle. If this is the case, return them, or take them apart and see if some rough egdes on the interior parts are causing the clamp to hang up. There is definitely some acquired feel to using these, and only us cheap home shop machinists use them. The pros use rather fancy direct-reading bore gauges. The REAL pros use Cadillac air gauges, but these are REALLY expensive. For smaller holes, pin or plug gages are relatively cheap, and work VERY well at sizing holes up to 1/2". Jon ------- Date: Tue, 5 Mar 2002 23:38:26 EST From: LADDERBARx~xxaol.com Subject: Re: telescoping gages You must put the gage in over center (Handle tilted up or down) tighten up the handle rotate it over center pull it out and then you have a size. have fun Mike ------- Date: Thu, 07 Mar 2002 14:52:11 -0800 From: Ben Bennett Subject: thanks-re telescoping gages Thanks for all the advice on using my telescoping gages, except for the wise guys that told me to take them apart.... boy! What a lot of little parts & springs. Maybe the best advice was to throw them away. I think I've got a pretty good idea now. Cock it, release it, cock it the other way, pull it out and measure. I think my trouble was I was I was wiggling it around, trying to get it perfect after I set it. Ben Bennett ------- Date: Mon, 11 Mar 2002 16:20:56 -0800 From: "Van Lupo" Subject: Indicating using electrical contact Is it just me or have others figured this out? I bought a "Signal Lite" edge finder the other day that uses electrical contact to detect the edge of a work piece only find out that it wouldn't work on the Sherline machines. Well being an electrical engineer and all, I quickly figured out the problem. It turns out (not too surprising actually) that because the Sherline cross slides are all anodized, there is little chance that electrical current can ever flow between the work piece and the spindle or cutter in the case of the Lathe. That's when the lights went on (pun intended!). So, I thought I would share my excitement (pronounces discovery). Using a simple conductivity meter or light you can connect one lead to the spindle or tool and the other to your work piece and then simply bring the tool into contact with the work piece and when it touches the conductivity indicator will let you know where the surface or edge is. Simply subtract out the proper tool compensation and your good to go. Now my question to the list is, is there really anything wrong with using this technique for determining the edge or surface of the part? I can't seem to see any reason why this couldn't be used in place of a dial or test indicator either. Simply note the hand wheel settings at two different locations and then take the difference to adjust the work position. Anyone have comments on this? Van ------- Date: Tue, 12 Mar 2002 14:10:03 -0000 From: "docholliday01201" Subject: Re: Indicating using electrical contact Have done it for years. I use a multimeter on resistance setting which has beep on full continuity. I use big alligator clips one on work one on the spindle at the top where the drawbar is. Usually the beep tone is all I need, sometimes I have to watch the resistance on the meter for sudden change. The only drawback is that if there is a chip there it will short it out and give an innacurate reading, or if your coolant is conductive. (I use non-conductive ethylene glycol.) The meter is part of the shop tools now !!! ------- Date: Tue, 12 Mar 2002 20:06:52 -0000 From: "flosi2001" Subject: Re: Indicating using electrical contact I use a homebuilt conductivity probe that I made long time ago from plans in a magazine. It is a very simple gadget, that lights a diode when the resistance is less than 10 ohm. I have also tried my multimeters for this, but they don't work as well as they peep at a much higher resistance. Flosi Gudmundsson Iceland ------- Date: Sun, 17 Mar 2002 23:33:15 -0000 From: "gbesch" Subject: Re: Instruments In sherline, "Graham Knight" wrote: > Now that I'm back from holiday and have time to use > my new Sherline lathe, I intend to go and buy > myself some measuring equipment this week Graham, besides a good set of calipers and micrometers, the only instrument I consider a "must have" is a dial indicator. However, it's also nice to have a dial test indicator. Sometimes it's the only way to center a part in the 4-jaw, as when you have a part with an irregular outer surface, but which has a finished center hole. The lever of the dial test indicator can ride against the inside surface of the hole where the dial indicator simply can't reach. Over the last few years I've accumulated a basic set of instruments one-by-one as the need arose for different jobs. I have several dial indicators of various lengths from .5" to 2". I also have a set of 0- 3" outside micrometers, a depth micrometer, three dial calipers (two 6" and one 4"), and a dial bore gauge. I wish there were a good supply of used instruments here! As you've observed, a magnetic base isn't much good on the lathe cross-slide. However, you can get a bit of steel plate to put down in front of the lathe for the magnetic base to stick to. Another option is a shop-made indicator holder for the lathe cross-slide. I made a simple one as follows: Using a 2" length of 2x1" aluminum bar, face off the top and bottom. Put a clearance hole down through the top for a 10-32NF clamp screw, about a half-inch from one side of the 2" width (leaving room for boring a hole for the indicator without running into the clamp screw). Counterbore the bottom of the hole for a Sherline T-nut. Clamp the new indicator tool post to the cross-slide, mount the drill chuck in the headstock, drill and ream a hole for a close fit on the indicator tube (drilling from the headstock insures your hole will be at the lathe center height). Last, cross-drill down from the top of the new tool post into the hole for the indicator tube, thread 10- 32NF for a clamp screw to hold the indicator in the tool post. A nice accessory for your new lathe indicator would be an "indicator bridge". It's just a little makeshift item to assist in centering square, hex, or other irregular shaped parts in the 4-jaw. Get yourself a bit of flat spring metal (banding strap from an old packing crate or skid works well) about a half inch wide by about three inches long. Drill a hole near one end for a 10-32NF clamp screw, then put a right-angle bend about three quarters of an inch from the drilled end. Make sure it's nicely deburred all over, and you may want to lightly radius the top corners (the opposite end from the bend). You can use it as-is, or you may want to make a base for it to make it more convenient to set up. To use it, mount it to the cross-slide so that it's square to the side of the part you're trying to center, then bring your indicator up to bear against the bridge. As you turn your part to center it, the outer edges should just contact the bridge, causing a reading on the indicator. It's more convenient than having to pull the indicator rod away from the part as you turn it and it prevents bent indicator rods. I hope you enjoy your new Sherline! Greg ------- Date: Mon, 18 Mar 2002 01:41:12 -0000 From: "kentfreeman" Subject: Re: Instruments On the Sherline web site there is a picture of someone using the headstock riser block and the riser tool post. The dial indicator was inserted in the 3/8 hole in the riser tool post. ------- Date: Sun, 14 Jul 2002 00:48:21 -0000 From: "neilunreal" Subject: Re: Indicators Dial test indicators and dial indicators both measure the same thing, distance, but they do it in different ways. A dial test indicator measures distance by angular deflection, while a dial indicator measures it by means of a rack or piston. As Forrest pointed out, one of the results is that it's easier to make a dial test indicator which measures larger distances. It also makes each of the two types of indicators appropriat for different types of measurement. For instance, it is easier to use a dial test indicator to align the milling head and any parts to be milled. On the other hand, a dial indicator can be useful for situations where the absolute distance is important at two different points on a part. I find I nearly always use my dial test indicator for milling alignments, while my dial indicator is often handier on the lathe. If I had to have only one or the other, I'd have a dial test indicator, since it can be used in many of the same situations where a dial indicator is used, and in other situations where the use of a dial indicator would be almost impossible. So I compromised -- I bought a really good dial test indicator and a less expensive dial indicator. Neil ------- Date: Sat, 13 Jul 2002 21:20:22 -0400 From: "Marshall Pharoah" Subject: RE: Re: Indicators This is a good summary. I would like to add that because a DTI works by angular deflection, that the readings from it should not be taken as gospel, especially over a distance of more than a few degrees. I believe this is called tangential error, but my math is extremely rusty. The rule of thumb is: Use a dti when testing alignment. Use a dial indicator for measuring distance. Note that when measuring distance with an indicator, you still can introduce errors due to improper alignment (the indicator becomes the hypotenuse of a triangle and may read less than the acual movement. If you walk into a shop around here, you'll see the pro's using Starret Last Word DTI's or Browne & Sharp, Mitutoyo, Fowler, or a couple of other good brands. For travel indicators they use the cheapest they can get. $6.99 specials from the truck sales if they can get them. DTI's are almost always used with the machine off and are at little danger. Travel indicators are often used with the power on, occaisionally even sacrificed (Watched a machinist take a cut right through the top of one once, on purpose, there was no way to remove it without losing the setup). So, generally, you need both in your shop. I have a Browne and Sharpe Bestest DTI, a Brown and Sharpe 1" Travel indicator, a federal .0001 indicator and 4-5 el cheapos travel indicators. Marshall ------- Date: Sat, 17 Aug 2002 23:39:30 -0000 From: "variousgroups" Subject: finding center of small hole What is the best way to find the center of a small hole, say under 1/4", in a flat piece, not thick, that is being brought to the machine for the first time? The hole was bored somewhere else. You want to lower an end mill of a lesser diameter into the hole and create a key hole-type result. If you place a lesser diameter drill rod in the chuck and measure side to side in X and Y, how do you really know when you've made contact at the sides, or that you're on a diameter? Successive approximations sounds fairly time comsuming and inexact. You could measure electrical continuity easily enough for contact, but what if the piece is Delrin? Does one just have to gauge it by a "tips of the fingers feel" on the lead screws? Any thoughts? Mike ------- Date: Sat, 17 Aug 2002 20:15:33 -0400 From: "Daniel Munoz" Subject: RE: finding center of small hole Here's my quick & dirty method (from a beginner that blindly think he'll become a machinist some day) I use a Sherline lathe dead center, stuck it in the motor taper shaft, and while slowly setting the Z-axis down I manage to center it on the hole until the dead center is low enough to fill the hole completely. Then I clamp the piece, the vise, the rotary table or whatever hold the piece to machine, and voila, I have centered the hole around the dead center's cone. Hum, not the most accurate solution I'm sure, but it was enough for many of the things I needed to do for now. Daniel http://www.nutsnbits.com ------- Date: Sat, 17 Aug 2002 22:03:43 -0400 From: "Van Lupo" Subject: RE: finding center of small hole You use a hole center finder device that you mount in your end mill holder and then spin a low RPM. When it makes contact with the side it will true up until it then kicks out to the side. Record the hand wheel value and then go find the other side and record that hand wheel setting. Subtract one from the other and then divide and you have the center. Repeat for both axis until they match. Takes about three to four passes. That's how I've been doing it anyway. Would love to hear how others solve this common need. Van ------- Date: Sun, 18 Aug 2002 03:50:34 -0000 From: "variousgroups" Subject: Re: finding center of small hole Van--Is the "hole center finder device" that you use the same as an edge finder? Using a dead center sounds okay, in that a cone held in a chuck or in an end-mill holder ought to "find" the center of the hole, but irregularities in the hole's outer rim will invite imprecision. Perhaps one solution is just to run a fine, flat sharpening stone lightly over the surface around the hole first. Clamping will introduce some imprecision, too. But then again, this is a hobby-type tool. Mike ------- Date: Sun, 18 Aug 2002 00:17:08 -0400 From: "Van Lupo" Subject: RE: Re: finding center of small hole Mike, a hole center finder is very close to the same as an edge finder except that the end is a pointed cone rather then a straight. Beyond that the device works the same way as an edge finder. Van ------- Date: Sat, 17 Aug 2002 21:36:44 -0700 From: "Marcus & Eva" Subject: Re: finding center of small hole The best and most accurate way is with a dial test indicator. My Mitutoyo has a 0.030" tip so I can indicate a 0.050" hole directly. Anything smaller, I push in a gage pin of the right diameter and then indicate the pin. Cheers Marcus ------- Date: Sun, 18 Aug 2002 07:51:12 -0500 From: "Nance, Tom" Subject: RE: finding center of small hole Hi Van, That sounds like a very elegant way to find the center of a hole but I see a major problem. To move from one side of the hole to the other you must, of course, change direction of the table movement. When you do that, you introduce backlash into the scheme and you won't get a true reading from your handwheels. Sorry, but that's one of the vagaries of driving a mill. The only way I have found to find the center of a hole on the mill is to mount a Dial Test Indicator in the mill spindle and indicate the inside of the hole as someone else mentioned earlier. It's a real pain in the neck - and I mean that quite literally because the dial moves around and so YOU have to move around with it to see what it's reading around on the back side. Doing it that way is tremendously accurate and once you've done it a few times, you can center the mill fairly quickly. Tom Nance ------- Date: Sun, 18 Aug 2002 06:30:58 -0700 From: "Dave Hylands" Subject: RE: finding center of small hole If you have one of the edge finders that shoots to the side when you hit the edge and comes back when you back away (they have a spring in them), then you can eliminate the backlash problem. This of course, only works for holes larger than the edge finder, typically 0.2". You find one side the traditional way, moving the table until you just see the edge finder move. To find the other side, you move the table until you just see the edge finder move, and then to get rid of backlash, reverse direction until the edge finder has just gone back to center. You've now found both edges in one axis. Center that axis. Since you've eliminated the backlash, if you overshoot center, you need to overshoot in the other direction and come back from the side where you obtained the 2nd measurement. Repeat for the other axis. ------- Date: Sun, 18 Aug 2002 10:06:37 -0400 From: "Van Lupo" Subject: RE: finding center of small hole This is correct, but I might add that to do this accurately you must feed the hand wheel until the edge finder starts to spin true and then just a little more and the edge find then kicks off to one side. It is at this very point that the find kicks off to the side that you want to read your hand wheel setting. As Dave mentioned you must always subtract your previously measured backlash from the hand wheel readings each time you change direction. This is true for any measurements you make using the hand wheels. I might also mention that it is very important to make certain the hole is clean around the edge your taking your measurements from. Any burrs will obviously drastically affect your outcome. As mentioned in previous post, a dial indicator is much more accurate but also requires considerably more setup effort and time. Also is generally better used on larger holes I think. Van ------- Date: Sun, 18 Aug 2002 10:14:39 -0400 From: "Dan Statman" Subject: Re: finding center of small hole > That sounds like a very elegant way to find the center of a hole but I > see a major problem. To move from one side of the hole to the other you > must, of course, change direction of the table movement. When you do > that,you introduce backlash into the scheme and you won't get a true > reading from your handwheels. Sorry, but that's one of the vagaries > of driving a mill. Do you not have an indicator set up to measure the actual table movement? Or do you solely rely on your handwheels? With a plunger type indicator you can easily measure the actual table movement and then abcklash is NEVER an issue for this. This is also what is needed to measure the value of the backlash. Daniel J. Statman, Statman Designs www.statmandesigns.com ------- Date: Sun, 18 Aug 2002 07:32:15 -0700 From: "Marcus & Eva" Subject: Re: finding center of small hole Hi Tom and others: Best way around the neck bending problem is to bum a small mouth mirror off your friendly neighbourhood dentist. They are only around 6 bucks orso, and dentists toss the scratched ones all the time. Going back to all the interesting responses we've had on this thread, the only good way to pick up a hole is with a dial test indicator. This is what everybody in the trades uses and with good reason. Edge finders are useless for small holes, and cone centers are hopelessly inaccurate. Edge finders are not terribly accurate either; even for finding edges. Many harder grades of steel will magnetize a bit when they are machined, and will yank an edge finder into the kickout position prematurely. They are therefore useless on steel!!! The best way to find the center position of a rectangular block to within tenths is to chuck a dowel pin into the collet and feel the gap with a feeler gage or a Jo block. If you spin the dowel by hand so you're always presenting the same point to the successive sides of the block, you can accommodate any runout in the collet and dowel. This is the fastest and most accurate method I have ever found to pick up a block center, and I have tried them all over the years. I've seen lots of toolmakers farting about with Dial indicators and edge finders and depth mikes. They all still routinely screw up the positions of their work by 0.001 to 0.002". I can feel a movement of 0.0001" easily on the CNC or a tenths DRO equipped mill, with a feeler gage if I'm gaging whether the feeler will slip into the gap between block and dowel or not. For accurate location of a single edge, I use a similar method: I stick a Dial onto the dowel and spin it by hand. I set the clock so the runout reads identically on either side of zero, and then mark the zero positions on the dowel with felt pen. I mike the dowel across the zero positions and then feeler gage my way up to the edge with the dowel positioned to present the marked point tangent to the edge. Add up the feeler thickness plus half the dowel diameter, and set your offset. You will be within 0.0005" of the correct location without breaking a sweat. So toss your edge finders into the trash where they belong, and go score yourself a couple of hardened dowel pins. Your workpieces will thank you. That's my Sunday morning rant, and I'm stickin' to it!!! Cheers Marcus ------- Date: Sun, 18 Aug 2002 11:08:02 -0400 From: "Van Lupo" Subject: RE: finding center of small hole Sometime ago I posted another technique that I have been using with reasonable success. This involves a little electrics effort but is simple enough to put together. I simply use continuity tester and measure for continuity between my work piece and the machine tool. Of course this only works with metal materials it has been quite reliable. Only issue is finding the highest pint on the tool to make the contact with. Clip one lead to the tool or head stock and the other to the stock or hold down and you're ready to go. It turns out that with the anodizing used on the saddle and cross slides there is no continuity between the head stock or tool and the cross slide or stock mounted to it. Is anyone else using this concept? Van ------- Date: Sun, 18 Aug 2002 15:25:18 -0000 From: "variousgroups" Subject: Small Hole Concensus: dial indictate yes wiggler no The feeler guage method Marcus describes, which involves a dowel of known diameter, relies on known quantities and assumes their accuracy: the feeler gauge thickness and the dowel diameter. If these come from Starrett or Brown & Sharpe they ought to be as described. There is also some need to rely on a well-developed, probably over many years, tip-of-the-fingers feel to use Marcus's method correctly. Anyway, the consensus seems to be that indicating the hole gives very good results and is widely used. The only "center finder" tools I can find in MSC are the "wiggler" sets. The consensus seems to be that these are basically not worth their cost, at least in this small-hole context. Do they have any genuine uses? Maybe for larger holes? Mike ------- Date: Sun, 18 Aug 2002 11:57:26 -0700 From: "Yasmiin" Subject: RE: Small Hole Concensus: dial indictate yes wiggler no A wiggle has some definite uses and I for one couldn't do without one. Its not a center finder for an existing hole. However, it is the tool of choice when placing a drill on center on a piece of work that has been carefully laid out. With a wiggler you can place the drill over the cross mark for the center of a hole that is being drilled. The only more accurate method is the use of a centering scope. Of course, you can position all holes relative to one hole but that's a lot of work that isn't necessary in most cases. If you have a DRO then relative position is simple but older methods take some care to do well. Regards, Yasmiin ------- Date: Mon, 19 Aug 2002 19:30:13 -0700 From: "Marcus & Eva" Subject: Re: :getting holes in the right spot Hi Mike and others: Actually, the feeler gage method does not require any special feel to it. It is amazing the first time you experience it, but a movement of 0.0001" is easy to discriminate. A feeler gage that is just nipped so it drags will fall out by itself if a 0.0001" movement is made away from the part, and will be pinched too tightly to pull out easily if a move of 0.0001" is made toward the part. The best way to use this method quickly, is to advance the pin toward the edge until it is obviously too close to slide in the feeler. Push the feeler into the gap as far as you can and start moving the pin away from the part. Keep pushing on the feeler and keep moving the pin away until the feeler slips into the gap easily. Now lock the slide and take up the backlash in the leadscrew. Unlock the slide again and advance forward slowly while wiggling the feeler. When it just starts to drag, you are there. Since you measured the pin and the feeler, you don't need to care what size they are; any old smooth round pin will do. When I'm too lazy to pull the cutter from the collet, I just use its shank as a pin. If I don't have enough of the shank sticking out for a proper feeler, I use a bit of wire. When you're centering a block you don't need to account for runout either, because you always place the same point on the circumference of the pin against the surfaces that you are gaging from. Yasmiin: you commented on the usefulness of a wiggler. I find them occasionally very useful too. Here's an old toolmaker's trick that provides the best wiggler I've ever found. Take a lump of Plasticene and stick it on the end of whatever tool you happen to have in your spindle. Stick a small sewing needle or a straight pin into the plasticene so the point is roughly centered on the long axis of the spindle. Turn on the machine at about 1000 RPM or so. Hold a bit of any old thing (like your fingernail) against the side of the pin until the point runs dead nuts true. Now pick up your scribelines with a good spyglass and the point. You don't have to change tools, and you can set it up over and over in seconds. It's also dirt cheap and when the point gets dull, just toss it and raid the family sewing basket for another one. By the way, there is a bad habit that I've seen even "experts" writing "how to" articles in Home Shop Machinist and other magazines doing all the time. Almost everyone centerpunches the intersections of holes they intend to drill; even when they are drilling on the mill. Don't do it... it sets you back if you intend to put the holes in accurate locations. No one can freehand punch perfectly every time, and the punchmarks that are off position just obscure the intersection of the scribelines and pull the drillpoint into the wrong spot. It's a perfectly valid way to position rough holes on the drillpress where the part can flop around and center itself on the punchmark, but it's worse than useless on the mill. A far better way if you are positioning holes IN THE MILL that are not too critical, is to scribe your lines, and then pick up each line independently by just touching the point of a spinning centerdrill to the job and seeing where the dimple is in relation to the line. Once you've centered on the first line, zero your first axis. Now deliberately move off your first line a bit (say 0.050" or so) and pick up the other line the same way. Once you've picked up the second line to your satisfaction, you can just reposition to zero on the first axis and you are there. The secret to success with this method is to keep the dimples tiny, and to make a new dimple in a new spot every time you shift an axis around while you're trying to center it. Make them close enough to the intersection of the lines that you will drill them all away when you find the right spot and poke in the hole (centerdrill it first!!!). It's really fast, and surprisingly accurate. With a 10 power spyglass I can get holes within 0.003" without breaking a sweat, and I didn't have to beat the shit out of the job with a big prickpunch either. End of rant! :<) Cheers Marcus ------- Date: Mon, 28 Oct 2002 05:49:03 -0000 From: "Donald Clement" Subject: Locating with Dowel I had a part that was made on the mill with surfaces, slots and tapped holes at a 45* angle. A drawing of the piece is shown at http://groups.yahoo.com/group/sherline/files/side_plate_top_2.jpg The dimensions of the part are 1/2" thick x 3.5" x 3". The way that I machined the angled parts was to mount the part on a tilting angle table. Two 1/8" diameter pins fit into two predrilled holes in the part. This is so the part can be flipped 180* to be able to machine the 45* slots on the other side of the part and still retain the datum. The problem was how to locate the depth of the slots, depth of angled surfaces, depth of the 4-40 tapped holes and location of tapped holes from the edge of the part at 45*. My solution was to use an edge finder located on a 1/2" ground dowel resting on one edge of the part. A drawing of my setup is shown at http://groups.yahoo.com/group/sherline/files/tooledgefind.jpg Here I show the edgefinder locating the tangent of the 1/2" ground dowel. The upper corner of the part is then .5/(2^.5)+.25 or 0.603" from the tangent edge. I find the depth by bringing an endmill to be be tangent to the 1/2" dowel. The corner of the part is then 0.25" lower than the endmill. I have found that I can locate the surfaces and hole centers to with a 0.0005". Don Clement Running Springs, California Owner: Clement Focuser ------- Date: Mon, 28 Oct 2002 08:48:17 -0800 From: "Marcus & Eva" Subject: Re: Indicating in the lathe Hi Alan: When a hole or other feature is to be created in the lathe, the job has to be small enough, and the hole close enough to the center of the part to permit the part to be swung in the lathe and neither hit anything or be so unbalanced as to make the lathe start hopping around the room when you turn it on. That intrinsically limits what features can be placed on what jobs and where. If I need to machine an off-center feature, and it's GOT to be in the lathe, I've got two methods to approach it. Either I can make a round feature in the mill that I can indicate to (like a pilot hole or a boss swung on the job with a boring head), or I can make a packing block for the lathe that, when squashed between the edge of the job and the 4 jaw chuck, puts the hole in the middle of the stacked assembly. This second method has the benefit of balancing the job in the lathe so I can spin it up to speed without having to follow it around the room. When I indicate the job, I merely compare readings one side to the other and make the readings exactly the same. If the offset from the center of the block is small enough not to affect the balance of the job too badly, I calculate the difference in distance from one side to the other, and set my indicator to make this comparison. Since I've got a set of gage blocks, sometimes I'll stick a gage block to the job with a smear of Vaseline and indicate to the face of the gage block. Chinese gage blocks are dirt cheap...I've seen them go for 50 bucks on Ebay, and they're worth a lot once you know how to use them. (Don't be tempted to use them as packing blocks...they're so hard they'll crack as soon as you snug up the jaws!!) However, as you can see from this painful dissertation, it's usually easier to place off center features in with the mill, so, unless I'm not spoiled for choice, that's what I always do. Now that I've got CNC, I rarely expose myself to the agony of trying to machine off-center features in the lathe. Cheers Marcus ------- Date: Mon, 28 Oct 2002 13:10:52 -0800 From: Alan Marconett KM6VV Subject: Re: Indicating in the lathe Hi Marcus, yes, I could've bored the cylinder in the mill, guess I forgot that! The first boring operation on the Stuart steam engine project was on the standard, which was over 2" deep, and I did not have a boring bar for the mill that would do it. I probably would have been more comfortable there! I bored it in my EMCO 5" lathe (no CNC, yet...). I had to make a turning plate, and some slotted clamps to fit the feet of the standard. Yeah, I put a few things I've learned to practice! Pix on EMCOCOMPACT5USERS list, photos, KM6VV, in case the link below gets trashed. http://photos.groups.yahoo.com/group/emcocom pact5users/vwp?.dir=/KM6VV&.src=gr&.dnm=10Vstan dard7b.jpg&.view=t&.done=http%3a//photos.groups.yah oo.com/group/emcocompact5users/lst%3f%26.dir=/KM6VV%26.src=gr%26.view=t Not sure what you mean by "gauge blocks", I have a set of cheap 1-2-3 blocks, which come in handy for setups. Best regards, Alan KM6VV ------- Date: Mon, 18 Nov 2002 19:40:59 -0800 From: "Marcus & Eva" Subject: Re: Edge Finder From: "Ned Carey" > What do yo all use as an edge finder? All that I have found are > too big to fit into a Sherline collet. Thanks, Ned Hi Ned: A dowel pin and a feeler gage works just fine. Don't bother with one of those eccentric spinning ones. They don't work well enough to be worth it. Cheers Marcus ------- Date: Mon, 18 Nov 2002 22:14:22 -0500 From: RichD Subject: Re: Edge Finder Ned, there is a 3/8 diameter version to be held in the 3/8 endmill holder. Alternatively, a dowel pin can be used with a strip of .001" shim. Lightly pinch the shim between the part and the pin and subtract .001+1/2 pin dia. RichD ------- Date: Mon, 18 Nov 2002 19:48:44 -0800 From: "Dave Hylands" Subject: RE: Edge Finder > I've heard of wiggler sets before but I don't understand how > they work. I get the idea that the point is just trued to be a pointer > but how are the balls used? Hi Ned, the beauty of this style of edge finder, is that it doesn't matter how accurate the holder is. A wad of gum and a pin would work similarly. The bottom part has a tendency to either wobble off center or sit at the center of rotation. For the wiggler, you get the ball running true (like the pointer) and move towards an edge. When you hit the edge, the ball flips to the side, and you're half a ball diameter away from the edge. Dave Hylands ------- Date: Tue, 19 Nov 2002 03:52:21 -0000 From: "ptlarry2003" Subject: Re: Edge Finder Ned, a Starrett #827B will fit the 3/8 end miller holder. Larry M. ------- Date: Wed, 11 Dec 2002 12:16:46 -0500 From: "Dan Butler" Subject: Re: Indicating Question I have more than a few dial test indicators that are junk and brand names in a draw. I find one of the nbest DTI's is the "Interapid 312B". These cost dearly at around $200, but I find them new on ebay routinely at much less. Worth waiting for in my estimation. Have fun. ------- Date: Thu, 19 Dec 2002 00:28:40 -0800 From: "Dave Hylands" Subject: RE: Dial indicator Hi Scott, I don't have a tutorial, but I have a picture of using the dial indicator to setup some material in a 4 jaw chuck. http://www.davehylands.com/Machinist/Modifications/Taig-Slitting-Saw-Ar bor/06-Indicate.jpg [INCLUDE 6-Indicate.jpg in the address] Basically, you need something secure on the machine to fasten the dial indicator to. I like using the cross slide, because it allows me to move the dial indicator into position easily. With the 4 jaw, You can generally eyeball the jaws into a few 10's of thousandths by comparing the jaws with the concentric rings on the chuck face. I then work on pairs of opposing jaws. I get one of the jaws lined up parallel to the dial indicator, and get the dial indicator going towards the center. Note how far, and in which direction the dial indicator moves when you move the 4 jaw 180 degrees. You need to move the piece by half the difference. You need to loosen the jaw on the side with the low reading and then tighten the jaw on the other side. Remember that one complete revolution of the screw on the jaw moves the jaw 0.050'. After making a substantial movement with one pair, I usually switch to the other pair so they're both moving in. It usually only takes 2 or 3 adjustments to get things within a thousandth. Always remember to measure one more time after you've done your final tightening. Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Mon, 23 Dec 2002 08:51:05 -0500 From: Charles Gallo Subject: Re: Starrett/Mitutoyo On 12/23/2002 jerdal wrote: Mitutoyo is quite nice, work fine, built well, last a long time > with reasonable care. I would avoid "digital" in favor of dials, > which work all the time, not just when the battery is good (or when > all the little counter parts are good, for "mechanical digital"). > Your opinion may vary, and you are welcome to it. I'll second the Mitutoyo stuff being good - In fact, I think they make the BEST digital calipers around. However, I will disagree with "avoid 'digital' in favor of dials". I have the Solar Absolute Mitutoyo calipers - I'll never go back! The BIG features is that I can set a zero at the Nominal, and have an exact reading on how much to remove, AND I can work in metric any time I want. A LOT of what I have to do is metric (I make parts that fit cameras). Let's say I need to make a 3.5mm part. I close the calipers - zero them, set them to metric mode, open to 3.5mm, rezero them, and change them to inch mode! Now when I take a measurement on the lathe, I get a reading of how much stock I have to remove in thousandths, divide by 2, and start taking cuts. One day, I will be able to afford a DRO on my machines. Charlie ------- Date: Mon, 23 Dec 2002 11:06:39 -0600 From: "Richard Meredith" Subject: Re: Starrett/Mitutoyo Mitutoyo make very good instruments. I have come to be wary of used Mitutoyo calipers though. Their mechanical calipers have plated brass racks which can be easily damage with abuse. To often the used units on ebay have been abused. Starrett, and believe it or not most of the cheap Chinese dial calipers use stainless steel racks which hold up much better to misuse. A six inch Chinese caliper can be had for less than $20.00 new from just about any tool suppler (Enco, JTS, Wholesale Tool, Etc.). These units are quite accurate, and almost bullet proof. It has been my unfortunate personal experience that electronic calipers can be easily damaged, though any instrument is a good instrument if properly used and cared for. By the way, if you do go digital, inspect the batteries for any signs of leakage as soon as you get it, remove the batteries before storing away for a prolonged period. Good luck, Rich ------- Date: Tue, 24 Dec 2002 23:44:23 -0600 From: "jerdal" Subject: Re: Re: Starrett/Mitutoyo On 12/24/2002 jerdal wrote: Sorry right back at cha'. >My Kanon 6" caliper from the 1970's checks out against gage blocks >as near as dead-on as I can see on its dial. >Want me to send you the links it the Accuracy specs? Should I continue? >Based on the BEST Calipers (The Starrett Master Verniers) being .0005 >and the WORST Micrometers being .0001, your talking 1/2 a decimal >place difference!, and the best "pocket" mikes (I didn't even spec >"bench" mikes) being a full digit better - Not sure what you are driving at, whether you are agreeing or violently disagreeing, or if you saw the point..... There is accuracy, there is readability/resloution, and the two don't necessarily have any relation. A caliper or mic could be actually accurate to 0.0005, and be "readable" only to 0.005 due to the dial or thimble. The accuracy does you no good in that case. Or it could be marked in tenths and accurate only to nearest thous. Still not helpful, but this time it tells lies. At least the other case is honest. Just because "calipers" (or mics) CAN be out 0.001, or 0.003 or 0.0005 or whatever, doesn't mean THAT particular set right there is out that much, either. I could not care less what the specifications of any crowd of calipers is, I calibrated mine, and they agree with my friends at Brown and Sharpe as closely as I can read them. Which is another point, BTW, as I mentioned, the dial isn't made to read closer than about 0.001, (that is its "readability" or "resolution") maybe a half if you look closely. But most calipers will dodge about a half thou just from how you hold and close them, whether you close at tip or towards the stock, etc, so that isn't generally a problem. Micrometers are much more accurate if made that way. If not, they are crummy c-clamps. Plenty of "readable to 0.001 only" mics out there too, and they are maybe no better than a good set of calipers. I have one reading to tenths, which also agrees with my friends at B&S, to 0.003, and I trust it for close measuring more so that the caliper. But the caliper gets used for most general stuff, cuz it's good enough, and it's right there, with a dial, marked in inches and MM. Nuff said. Jerrold ------- Date: Fri, 10 Jan 2003 10:57:49 -0800 From: "Doug Kelley" Subject: Re: Jammed "Last Word" sherlinex~xxyahoogroups.com writes: >My Last Word DTI just had a sudden meeting with the concrete floor in >my shop. Nothing appears to have been injured but the needle no >longer moves. Is there anything that I can do to unstick it myself >or does this mean another expensive trip back to Starrett? Any >suggestions woild be greatly appreciated. Nelson Wittstock Medina, Ohio Same thing happened to me a few days ago with a cheaper unit. I took it apart and put it back together. Didn't really fix anything; I think something was jammed. It works now but it "sticks" a few thou here and there. I think I'm going to take it apart again and see if there's anything bent in it. The way I look at it, since it was already broke there's no harm in dinking around with it... Doug -------- Date: Fri, 10 Jan 2003 11:09:42 -0800 From: Brian Pitt Subject: Re: Jammed "Last Word" That's the problem with the expensive ones -- they sound just like the cheap ones when they hit the floor ;) Anybody ever heard of someone actually wearing out an indicator? Brian -------- Date: Fri, 10 Jan 2003 21:38:36 -0800 From: "Marcus & Eva" Subject: Re: Jammed "Last Word" Yep: I wore one out...lent it to a friend, he chucked it up in the mill, spun it up to 3000 RPM, and wore it out real fast!!! Cheers Marcus ------- Date: Fri, 10 Jan 2003 13:03:16 -0600 From: "Bad Brad" Subject: Re: Jammed "Last Word" Nelson, what usually breaks is the pivot pin. Forrest ------- Date: Fri, 10 Jan 2003 12:19:05 -0800 From: "Orrin B. Iseminger" Subject: Re: Jammed "Last Word" You should be able to fix it unless something is broken. As someone else mentioned, check the pivot screw near the stylus. I'm sure it's all right, but just check. Next, remove all the threaded plugs from the body so you can see what's inside. There are two likely things that happened inside: 1) The pointer shaft jumped off its pivot. If you look inside you'll see a spiral cam. Take a toothpick and try to manipulate it. If it doesn't flop around, you're probably all right. 2) If the spiral cam is all right, check to see if the jewel-tipped lever arm has popped out of the spiral cam. If it's in the groove, you *might* be o.k. More on this, later. If 1 & 2 seem all right, check the pivot, again. Does the stylus moved the pivot and lever arm at all? If not, the pivot screw may be bent or jammed. Taking the proper size screwdriver, try loosening the screw just a hair. Don't overdo it. If you loosen it too much, the jeweled lever will pop out of the spiral cam. The object is to make sure the stylus and lever are moving freely. Remove the stylus, completely. Just turn the locking lever a quarter turn and lift it off. Does this free up the movement? If so, the head of the pivot screw is probably rubbing on the side of the cavity on the big end of the stylus. Be sure the stylus is properly seated. I sometimes have to open up the walls of the cavity with a small stone mounted on my Dremel tool. If the pivot seems to be all right, check that spiral cam, again. The jeweled tip of the lever must fit into the groove. If you're still not getting any movement, there's a chance that the jeweled lever has jumped its track and then dropped back down into it after the pointer has moved a full turn. The Last Word pointer must have one full turn of spring preload. Here's how I set it: 1) Loosen the pivot screw enough to allow the jeweled lever to lift out of the spiral cam. 2) Make sure the pointer has returned to its "relaxed" position. That is, the hair spring isn't in tension. 3) Insert a toothpick into the spiral cam groove and by moving it sideways, cause the pointer to rotate one turn. (You'll have to make sure you turn it so as to "wind up" the hair spring.) 4) While holding the pointer in this position, insert the jeweled tip of the lever into the cam. Then, pinch the lever to hold the tip in place. 5) You can now release the toothpick. Then, use a jewlers' screwdriver, tighten the pivot screw enough to hold the lever in the spiral cam groove. Obviously, the pivot screw cannot be fully tightened. The Last Word is designed to hold it wherever you set it. If none of this works, send it away. Something is probably broken. It's my bet, however, that you'll be able to fix it. If you don't have a set of jewelers' screwdrivers, go to Radio Shack and get a set before you do anything. Good luck, Orrin B. Iseminger Colton, Washington, USA http://users.moscow.com/oiseming/lc_ant_p/index.htm ------- Date: Sat, 11 Jan 2003 00:56:46 -0000 From: "Nelson Wittstock" Subject: Re: Jammed "Last Word" My DTI is now unstuck and I am trying to get the spring reload adjustment taken care of. I'm having to sort out which of the three screws does what. Is the little screw on the back of the body the pivot screw? The large headed screw on the side appears to act as a stiffener of the movement of the cam. I had thought that the screw at the stylus end was fully snug before but that seems to restrict the movement of the lever when I have it tight now. Your instructions have been a great help so far. Thanks, Nelson ------- Date: Fri, 10 Jan 2003 21:08:11 -0800 From: "Orrin B. Iseminger" Subject: Re: Jammed "Last Word" What I called the pivot screw is the one out at the end. The head of it is covered by the stylus. One side of the body of the Last Word has the reversing lever. On the opposite side is a large slotted screw (cap). If you will remove this cap you can see the spiral cam and the tip of the jeweled lever. (As Forrest said, not all are jeweled.) You can do your necessary inspections through this opening. Depending on how your Last Word is set up, you may also have another large cap at the end of the body. You can remove this cap for further visibility. This threaded opening is for attaching fittings to a mag base, or whatever. Be sure to replace all the caps in order to help keep out the swarf. Good luck, Orrin ------- Date: Sat, 01 Mar 2003 07:32:38 -0000 From: "int3man " Subject: 1/4" Shank Edge Finder I wanted to take a moment to share with you a 1/4 shank edge finder that I found. Not only does he make an edge finder but he also makes a center finder of the same configuration. These fit our Taig Mill's collet selection. Fisher Machine Hawthorne CA. Phone (310) 644-83765 Email Fishermachinex~xxaol.com Tell John that you found him on the Taig users group and you'll get a smiley face on your receipt. Actually for $10.50 plus $5 freight you'll get an Edge finder that you can use. + Tax if you live in CA. Enjoy! Michael :-) ------- Date: Sun, 9 Mar 2003 14:10:20 -0800 (PST) From: Pete Brown Subject: indicating/squaring up work Without purchasing something like a dial indicator (I'll likely eventually get one, just not right now), what are good ways to ensure that work is square to the table? I've found that due to clamping locations and other factors, it isn't always possible to use a machinist's square easily to ensure the work is square to the table (and to the cutter). Suggestions? Or is the dial indicator really the only reliable way to go? Thanks. Pete ------- Date: Sun, 9 Mar 2003 16:46:41 -0600 From: "Al Lenz" Subject: RE: indicating/squaring up work Pete, you might try this: Replace the cutter with something smooth such as a dowel or drill shank. Bring it up to one end of the edge that you want to true. Adjust the dowel using a feeler (could be shim stock or even paper) till it just touches the edge of the work. Note the hand wheel reading. Back off from the work and repeat for the other end. This will tell you how far you need to move that end to get true. Slightly loosen the clamp on that end and tap with your soft face hammer. This is easier with a dial indicator since you can leave it in place and see exactly if and how much the work moves with each tap rather than trial and error, but it isn't that hard. al ------- Date: Sun, 9 Mar 2003 19:59:47 -0800 From: "Marcus & Eva" Subject: Re: indicating/squaring up work Hi Pete: One toolroom that I worked in, had a row of holes drilled and tapped into the side of the mill table. They had a bunch of U shaped straps that were hardened and ground, so you could drop one over one of the screws in the side holes, and snug it down. That created a ledge against which you could push the job before tightening it down. The same toolroom had made up blocks to just push into the tops of the tee slots. You could push your job up against these as well. My favourite (although it won't work on a Sherline) is to use a couple of mag bases clamped to the edge of the table and then push the job up against that. The other reliable way is to clock it in. "Clocking it in" refers to the use of a dial indicator. Cheers Marcus ------- Date: Tue, 11 Mar 2003 08:38:05 +1200 From: "Richard T. Perry" Subject: DTI You've gotten several suggestions, and I'll make two more - 1) When using a machinist's vise, I've tried "edge finding" the side of the vise (that I knew to be flat) at two spots, and adjusted it until the indicator popped over at the same hand dial reading at both spots. Kinda rough, but it works. 2) There are several plans out there for indicators, if you don't want to buy one ( I think there's even a serial in HSM right now...) For this job, you really don't care all that much what the readings are, just that the "deflection" of the indicator is minimum over the distance of the jaw... Regards, Richard T. Perry ------- Date: Mon, 07 Apr 2003 19:54:41 -0400 From: Daniel Munoz Subject: aligning the rotary table and the mill spindle I'm stumped with a problem that must be a simple one for the experienced machinist. I always had a problem indicating the center of the rotary table exactly under the center of the mill spindle. Usually, I have set on the rotary table the lathe chuck, with a piece of round stock from the lathe in it. To indicate the edges, I know how to use an edge finder, I have a Brown&Sharpe "audible" nice one for that purpose and use it quite easily to indicate on the vise the edges of an angular stock. But how to indicate the center of a vertical round piece on it's rounded edge, with the edge finder in the mill holder also in a vertical position? I can't indicate both sides of the round stock, say left and right, or front and back and then take the middle position, because the backlash needs to be taken into account and it's a pain. I could put the spindle in the horizontal position to find the middle of the stock, indicating on the back or front edges and then adding the radius of the stock, then back to the vertical position and indicating the left or right side + radius to find the center... but then I need to move the head of the mill, so carefully adjusted before :-) And most of the time the pieces I machine are so small the spindle in the horizontal position doesn't go low enough! So, for now on, I roughly eyeball center my work, of better I put the lathe dead center inside the mill spindle and carefully and slowly lower the dead center inside the rotary center hole until the rotary table can turn but not move, then I clamp it. but sometime I need an extra precision and I'm afraid I can't reach it that way. I also have a dial indicator at hand, and a strange wiggler thingy that I have no idea how to use, especially to solve this problem! Any better way to share? I don't know if my question is very clear, but any attempt to understand my gibberish and provide an answer is greatly appreciated ! Thanks ! Daniel http://www.nutsnbits.com ------- Date: Mon, 7 Apr 2003 20:55:53 -0400 From: "Statman Designs, LLC" Subject: Re: aligning the rotary table and the mill spindle Can't you use a dial test indicator held in a collet or small drill chuck in the spindle? If you turn a round bar true to the chuck on the lathe and transfer the chuck and bar to the rotary table. Then you can turn the spindle by hand with the DTI inserted and clock the test bar. Adjust the table to get it centered. Should take about 3 minutes after you get things set-up. A mirror helps when the DTI face is backwards. Daniel J. Statman, Statman Designs www.statmandesigns.com dan.statmanx~xxrennlist.com ------- Date: Mon, 7 Apr 2003 21:11:33 EDT From: JLFowlerx~xxaol.com Subject: Re: How to properly center the workpiece ??? I'm new to the forum, but I would like to put forth what works for me for your consideration: I have a sherline lathe chuck (3 and/or 4 jaw self centering)I use it and a dead center (I made a few different sized ones to fit my favorite collets. Anyway, I use the center of the chuck (mounted in the rotary table - jaws closed) to find X and Y - rough; and, then a dial-indicator from there if needed - but that is rare for my work. Jim ------- Date: Mon, 07 Apr 2003 22:05:30 -0400 From: Daniel Munoz Subject: Re: aligning the rotary table and the mill spindle Ah yes, that's true. Never thought of it that way, thanks Dan ! And it is most certainly accurate with a careful adjustment, but it is not extremely easy to do, with the dial rotating... I bet it's more a 15min than a 3 min for me ;-) I'll give it a try, and will check that way how bad my centering method with the dead center is. ------- Date: Mon, 07 Apr 2003 21:21:07 -0700 From: Keith Green Subject: Re: aligning the rotary table and the mill spindle I run a mill as part of my regular work in a machine shop. I use both methods already described prior to this plus one more. The method of putting the center in the hole in the table is one I use for rough centering, followed by removal of the center and finishing up with the test indicator. I should state here that the indicator I use is a Mitutoyo (what I call a "finger" dial). This indicator with it's long reach and excellent accessories coupled with superior quality and small size have made it a favourite of mine over the years. Usually dialing up the hole directly is the most accurate; a dental mirror is my choice for its small size. Another one, as yet unmentioned here, is the one where you turn a precise- fit plug for your table hole. One one end it should be a tight sliding fit to the table hole and on the other it should be a tight sliding fit in your most accurate collet. Put the plug in either the collet or the hole and position the table so the other end of the plug slides into its respective hole. keith ------- Date: Tue, 8 Apr 2003 05:47:29 -0500 From: "Scott Peterson" Subject: Re: aligning the rotary table and the mill spindle I was faced with this problem in the past...asked a few questions here..and got some hints from a couple helpful members. (thanks much!) I ended up choosing to buy an inexpensive dial test indicator, (DTI) and have been "clocking in" my rotary table with great success ever since. There is one little fly in the ointment, though...just because the part was running true when the chuck was attached to the spindle, does not mean that it will be exactly centered on the axis of the rotary table when the chuck is attached there. This was driving me insane until someone in this group told me that this was not uncommon, (pretty much to be expected, even) and that I should always check the part for runout whenever the chuck is mounted to the rotary table...or even removed from, and remounted to, the spindle for that matter. If you're ten hours into a really complicated part...a five-minute check is far better than a big clunk in the scrap bin! Fortunately, I bought the independant four-jaw chuck, so re-centering isn't a problem...and I'd have to recommend using one if such swapping is to be done on close-tolerance or intricate parts. I just operate the rotary table/chuck/part with the DTI (mounted in a collet in the spindle) tip riding on the part after I get the assembly close to centered under the spindle...it shouldn't have much more than three thousandths inch (0.08mm) runout. I'm told that any more than that, and Sherline should be contacted for a replacement chuck-to-table adapter. I also noticed that the hole in my table is nearly a thousandth inch off center...so, even if the adapter and all threads were clean and dead perfect, there would still be runout. Once the part runs true when the rotary table is operated, you can then finish centering the table/chuck/part by rotating the spindle/DTI and noting readings on the DTI, adjusting X and Y handwheels as needed... you're centered when you can rotate the spindle/DTI seeing minimal change in the reading on the DTI dial. Does this all ring true with the more experienced members of the group? If not, feel free to "square me away"! It seemed that everyone was assuming the chuck would automatically center on the rotary table. I felt it necessary to mention the problem I ran up against, and the steps I take to get around it...if someone has a better method, I'll certainly give it a try. Best Regards, Scott Wisconsin, USA ------- Date: Tue, 08 Apr 2003 08:37:43 -0400 From: Daniel Munoz Subject: Re: aligning the rotary table and the mill spindle > precise-fit plug for your table hole. One one end it should be a tight > sliding fit to the table hole and on the other it should be a tight > sliding fit in your most accurate collet. Put the plug in either the > collet or the hole and position the table so the other end of the plug > slides into it's respective hole. Thanks Keith and all for your answers. Ah ! This is basically what I what doing with my dead center in the rotary table hole, but turning a plug to fit and slide in both holes is a much better idea than centering the dead center cone ! Thanks Keith !! I'l do that, and check the accuracy of the result with the dial indicator, using the method described before. Cheers. Daniel http://www.nutsnbits.com ------- Date: Mon, 14 Apr 2003 10:32:50 -0700 From: "Nicholas Carter and Felice Luftschein" Subject: Fisher machine 1/4" shank edge finders I am now offering the Fisher Machine 1/4" shank edge finders, all the details: http://www.cartertools.com/fm.html See our web pages http://www.cartertools.com/nfhome.html ------- Date: Sat, 03 May 2003 08:48:42 +0100 From: Tony Jeffree Subject: Re: edgde finder At 02:23 03/05/2003 +0000, you wrote: >Another question. I don't know what I would do without these >groups. I bought one of Nick Carter's 1/4" edge finders and a >beautiful piece of work it is. Unfortunately it doesn't talk to me >so I don't know how to use it. It is the audible variety and it >does in fact click as it touches the edge of the work piece. Now >what? I am at the edge in relation to the edge finder. What does >that translate to regarding any other tool. Please forgive me if >this is obvious to the rest of humanity. Jim - The tip of the 'finder is 0.2" diam, so it tells you that the milling spindle axis is 0.1" (half the diameter) from the edge that you have "found". If you were wanting to take 0.025" off that edge, then you would be "spot on" for using a 1/4" end mill to do the job (which has a radius of 0.125"). Regards, Tony ------- Date: Sat, 3 May 2003 09:11:37 -0700 From: "Carol & Jerry Jankura" Subject: RE: edgde finder Hi, Jim: When using any edge finder, the object is really to be able to place the center of your spindle directly above one edge of the object you're working with. All edge finders will specify the diameter of the probe (the part that moves and 'clicks' when it touches the edge). When the edge finder 'clicks' it means that the spindle center is exactly 1/2 times the diameter of the probe away from the edge. In my case (I don't have Nick's edge finder), the shank that the spindle holds is 3/8 inch diameter and the probe diameter is 2/10 inches. So, when I bring the probe to the edge, it means that my spindle center is exactly 1/10 inches from the edge. All I have to do is move the table exactly two turns of the handwheel (My mill has a 20 tpi leadscrew) and the spindle is centered on the edge. Once you know where the spindle center is in relation to the edge of your material, you figure any offsets to cutting lines based on the diameter of the cutter you're using. Carol & Jerry Jankura Strongsville, Ohio ------- Date: Tue, 27 May 2003 13:30:09 -1000 (HST) From: Tom Benedict Subject: Re: Re: Digital whatever... [Metal_Shapers Group] On Tue, 27 May 2003, dreilanderecht wrote: > Drifting off to one side a little, I saw an add for a digital dial gauge > the other day. Now, the way I use dial gauges, a digital one would be a > real pain. I use them to set up jobs concentric in the lathe, or more on > topic, setting things up in line on the shaper. For instance, setting a > vice jaw truly parallel with the ram. Now I can see that a digital one > would permit zeroing it at one end and reading the absolute error at the > other. But surely being able to see the swing of the needle is half the > point with a dial gauge? Put it this way, I wouldn't mind adding a > digital feature as well as the needle, but not instead. On those lines, > it is now popular for the better digital multimeters to provide some > sort of analogue indication as well, and you might notice that there is > a strong trend back towards watches with hands. I've had a use for digital indicators at my job. One of the things I'm working on is a really honkin' big digital camera ("Honkin'" is, of course, a technical term used often in the digital imaging field). Anyway, one of the concerns was that the focal plane of the camera was tilting with respect to the optics as it was being moved into different orientations. So we stuck three Heidenhain digital indicators between the camera body and the optics, and hooked them up to a DRO. The DRO unit had a serial output, and polling it to get the values of the three indicators was dead-simple. We set up a script to get the indicator values every five minutes, and put the camera through its paces. In the end we got really good data. I know it's not a typical use, but I can see the need for them. That being said, all the indicators in my shop are the dial type, and as you say that's the one I'd want for the bulk of the work I do. But no, "digital" does not always equal "better". Just a different tool for different jobs. Tom ------- Date: Tue, 27 May 2003 23:55:35 -0000 From: "dreilanderecht" Subject: Re: Digital whatever... Yeah, next time I set out to build a digital camera I will bear that in mind. :) The ability to log the data is potentially very useful, especially in test situations. Of course, the smaller the CCD device, the more critical the back focus distance becomes. But I get excellent value from a device my Dad made many years ago, a pointer that pivots on a ball and socket held by the lathe toolpost so that the tail end shows a magnified version of the movement at the headstock end. This is great for setting a punch mark to run concentric in the lathe for boring. I've also seen ideas for home made dial indicators with no calibrations. I used an Imperial dial gauge for many years with a metric lathe. The critical point there is simply that the pointer hardly moves when you pull the chuck around. Of course, if you want to set the job up eccentric by a known amount the calibrations come into their own, except that whenever I want to do that, the dial gauge never has enough travel. So I would be more likely to put the cost of a digital dial gauge into something a bit more applicable in a home shop, for instance I would really like a much longer Vernier or Digital caliper, say 18 inches or so. I can read quite accurately up to 8 inches or so with my current calipers, then it is back to the old steel rule. Fortunately few things of greater length really need to be made to within a thou or so, and you can often simply make sure parts match but a bit more accuracy in those longer lengths would be nice regards John ------- Date: Tue, 22 Jul 2003 15:16:39 +0100 From: Peter Harrison Subject: Re: Double end edge finder Neil Albert wrote: >I've already purchased a single end edge finder, but now I see that a >dealer has a sale on a Starrett double end edge finder >with the "other" end being a sharply pointed cone rather than >a cylinder for "locating center points and scribed lines." Is this side >of the edge finder effective? It would seem to me that if you can see its >point clearly enough to get it so close to the surface of the work to be >thrown off center by a scribed line, you would be able to visually >see if the point is directly over the line and not need the edge finder. I saw this very point (ooh a pun :) discussed recently. The pointy end is intended to be trued up with the spindle running. Use a ruler or some such until it runs perfectly straight. Now turn off the spindle and use the point to locate scribed lines. For crosses, do each line separately, looking along the line. Set your feedscrew handles or write down the readings and you are there. ------- Date: Tue, 22 Jul 2003 08:17:52 -0700 From: "Marcus and Eva" Subject: Re: Double end edge finder There was an extensive thread on this subject a while ago...I'm not sure now if it was on this list or the Jobshop Homeshop list. In a nutshell, I don't find edge finders to be all that useful...my preference is for a plain dowel pin in a collet and a feeler gauge. It's far more accurate and faster too. For the pointy end, a blob of plasticene and a stick pin are quicker and handier than the pointy end of the Starret style edge finder. So is a spyglass and the divot formed by just touching the point of the centerdrill to a scribed crossline. Check out the archives on all the details...it was a pretty thorough discussion. Cheers Marcus ------- Date: Tue, 22 Jul 2003 08:32:39 -0700 From: "Marcus and Eva" Subject: Re: Double end edge finder Hi Tom: The way to position the spindle axis over the axis of an existing hole most accurately is to spin a dial test indicator in the hole and adjust the table position until the clock reads no deviation as it is spun. The best way to determine a hole's position relative to a reference edge is to push in a gauge pin, clamp a flat to the reference edge and then slide a gauge block stack into the gap between them. Alternatively, you can lay the reference surface on a surface plate and pick up the height with a gauge block stack (or a Cadillac gauge) and an indicator. Of course, there's always the CMM for those with piles of cash. Having said all that, for most practical applications, pushing in a pin and depth miking from the reference face is more within the likely reach of a hobbyist. A dial caliper from the edge of the hole to the reference surface is used a lot too, and it's very fast but not reliable closer than about 0.002" The dial test indicator method of centering over an existing hole is also worth using in the hobby environment. Cheers Marcus ------- Date: Sun, 27 Jul 2003 10:47:35 -0700 From: "Dave Hylands" Subject: RE: Digest Number 1214: wigglers Here's a web page that describes what various wiggler probes are for: http://www.littlemachineshop.com/reference/wiggler.php Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Thu, 07 Aug 2003 20:41:00 -0000 From: "don_kinzer" Subject: Plans for Index Centers I found an article in Popular Mechanics describing how to make a set of index centers suitable for a smaller shaper or mill. I have scanned the pages and posted them on my website for those that are interested. http://www.kinzers.com/don/MachineTools/index_centers Don Kinzer Portland, OR ------- Date: Thu, 11 Sep 2003 16:51:30 -0400 From: "Ed Feuer" Subject: Re: center wobbler Hi all I have two beatifully made very old wobblers. One is a Brown & Sharp No.736 and the other is a Starrett No.55. They both have double gimballed spring loaded ends. If still made today, would cost a fortune. Never used them because the shanks are one inch high--never got around to making smaller shank because here's how I do it: Grind a point on one end of a thin (1/16 to 1/8 dia)steel rod 6"long or longer if your lathe can handle it. Grip the blunt end in the tailstock chuck and slide the tailstock to the left until the rod point is close to the workpiece. Then lock the tailstock and gently crank the rod in while guiding the point into the punch mark. Then mount a DTI on the toolpost and crank it in so that its plunger/lever rests on the rod at center height an inch or so from the work. There should be only enough pressure from the tailstock to keep the point in the punchmark. Then rotate the 4jaw by hand til the dti shows no runout. It took longer to write this than to do it. Hope someone finds this useful and cheaper. Regards Ed ------- Date: Sat, 11 Oct 2003 14:57:34 -0700 From: "Dave Hylands" Subject: RE: Centering Square stock > How do you go about centering up something square or rectangular > shape in the 4-jaw chuck. Do you scribe your lines and centerpunch > your holes, then use a wiggler or some other tool or tools to do this. I clamp an indicator to the cross-slide and use that. I work on the two opposing sides, and once I get them pretty close, I switch to the other two sides. Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Sat, 11 Oct 2003 23:50:28 -0000 From: "Graham Green" Subject: Re: Centering Square stock When you work out where you want the centre, hit it with a centre pop mark. Put the workpiece into the four jaw chuck and then bring the tailstock up to the workpiece, with a live or dead centre in the tailstock, now slowly rotate the workpiece and you will soon see where you have to push the workpiece to get it centred. Try it, it's real easy to centre something by using this method. radish ------- Date: Sun, 12 Oct 2003 22:06:58 -0000 From: "stevenson_engineers" Subject: Re: Centering Square stock Quickest production way to get to 0.001". Assuming square stock but will work on anything in the 4 jaw. Insert work into 4 jaw and centre as accuratly as possible by eye using the lining up rings on the face of the chuck. Then rotate work by hand so the work is square top to bottom and wind in the tool and just touch on the work, zero the dial if possible or take a note of the reading. Then turn the work 180 degree and do the same to the other side. The differance between the two readings is double what you need to move the work over. WORK WITH OPPOSITE JAWS ONLY. Rotate 180 again to the first side and recheck. When you are correct you should have the ssame dial setting on both sides. Then turn 90 degrees and do the other two opposing jaws. Sounds more complicated than it is and with a little practice you can get to a thou with no problem. It's very rare I even go to using a dial gauge to check the setting. John S. ------- Date: Sun, 09 Nov 2003 08:23:58 -0500 From: Ronald Thibault Subject: Re: Centering work in independant jaw, 4 jaw chuck >What is a good way to center work in a 4 jaw chuck that each jaw moves >independently? Thanks! Jeb Jeb; First mark your chuck (and jaws) 1 through 4, going around the chuck body. 1. As a previous post noted, roughly center the work piece using the rings on the chuck face as a reference. 2. Loosen just slightly jaw #2, so you can move the workpiece while adjusting the jaw 1/3 position. 3. Rotate the workpiece and position a toolbit so that it clears it through a full rotation, and note the dial setting (so you can between the following steps bring the toolbit back out so as to clear as you rotate the chuck). 4. At jaw #1, run the tool in until it just touches the work piece. Note the setting, and back the tool out to clear the workpiece. 5. Turn the chuck to jaw #3 and repeat step 4. 6. Halve the difference in the measurement. and rotate the work to the jaw that the workpiece was further from is at the toolbit side (pointed at you). Run the tool back in to the halved setting and move the jaws so as to bring the workpiece to just touching the bit. You have now brought the workpiece to a position where it is closer to centered in the jaw 1/4 axis. You may have to do this more than once, but for now "quite close to centered" is good enough. 7. Loosen just slightly jaw #1, so you can move the workpiece while adjusting the jaw 2/4 position. 8. Repeat the above for the jaw 2/4. 9. Go back around and check the workpiece position at all 4 jaws, and repeat the above, until the workpiece runs with little or no wobble. This may take several rounds of adjustment, depending on how close you got it positioned, with referencing the rings. 10. If this is close enough to centered for your needs, go back and check that all the jaws are tight, and start making chips. If not then continue. If more accurate centering is needed: 11. Clamp a 0-1" (0.001 accuracy) dial indicator to the cross slide so that it is horizontal, pointed perpendicular to the work piece, and set at the height of the lathe axis. With the chuck turned to jaw #1 run the crossslide in or out until the indicator is at about the center of its travel, with the needle pointing along the lathe (parallel to the work piece). Adjust the dial face so that it is zeroed. 12. Repeat the above sequence (steps 2 through 10), using the indicator to measure the position. 13. You positioned the needle parallel to the work so that it is easier to see which direction to move the work (I forget whether it should point right or left, it has been a year since I had my shop ready to resume machining, since my move), but when set correctly if the needle moves toward you shift work away from you. 14. You should be able to quite quickly get it within 0.001" with a little practice, and within 0.005" with a little care. If even more accuracy is needed change to a 0.0005" or 0.0001" indicator. Start with the 0.001" indicator first though, as the more accurate ones have a much smaller total travel, and might not have the range for the first go round. All the above is much easier if you have 2 chuck keys and can move the opposing jaws at the same time, rather than individually. Ron Thibault Warrenville, SC USA http://personal.atl.bellsouth.net/t/h/thib9564/ ------- Date: Sun, 9 Nov 2003 18:30:07 -0000 From: "Ernest Lear" Subject: Re: Centering work in independant jaw, 4 jaw chuck Sound long windy to me. I set the work piece in the chuck using the rings an the chuck for reference to get it some were near centre. Now with a dial gauge mounted near the chuck with the plunger set down vertically against the top of the work. You turn the chuck by hand a few turns and the gauge pointer will swing one way and then back the other way. Now all you got to do is hand turn the chuck until the gauge pointer reaches its lowest point. Stop. The jaw in the top position you slacken off a bit and now turn the chuck half of a turn and tighten this jaw now at the top, moving the needle back half the difference towards the position it was at when it was at its lowest point. Now turn the chuck around again until a new lowest point is found and repeat the above by screwing off the top. Rotate half a turn and tighten the top jaw so the pointer again move back half the amount. Just go on repeating this until the pointer show just a few thou from the lowest to the highest position. Now you nearly there, you just tighten the top jaw at now the pointer highest position until nil or almost nil movement of the needle is shown when you rotate your chuck a full circle. It seems a long job but try it. I normally take less than 2 minutes to centre any round work piece in a 4-jaw chuck and so will you after you tried the above method and got it sorted out. Ernest P.S.:-By the way I forgot to say that I use a dial gauge mounted on a magnetic based stand the type with a switch in the base. Magnetic and held down on the lathe bed way when in the ON and non- magnetic and free when this switch is in the other OFF position. This allow me to place the gauge with the punger pressing on the centre of the workpiece that in the chuck and vertically down agance it. And all the jaw adjustments are done when the jaw that being adjusted, is in the top upper most possition on the chuck. All the setting up is done by turning the chuck only slowly by hand. I hope this extra information helps in understanding how I do it. ------- Date: Wed, 03 Dec 2003 05:09:23 -0000 From: "Mitch Singler" Subject: 2 inch travel dial indicators [POSTED TO taigtools GROUP] I'm interested in adding dial indicators on my lathe X and Y axis, just like the ones Tom Benedict has designed for his lathe. Tom, if you read this, or if anyone else knows. I'm looking for two 2 inch travel dial indicators to add to my lathe. I have already made the mount and stop for my cross slide, I'm using a 1 inch indicator at the moment. Thanks for any recommendations and thanks to Mr. Tom Benedict for the great modification idea for the Taig lathe. regards, Mitch Singler ------- Date: Tue, 2 Dec 2003 22:00:30 -0800 From: "Dave Hylands" Subject: RE: 2 inch travel dial indicators I've purchased one in the past from JTS Machinery on eBay. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2575694333&ca tegory=11805 You can also call them and order direct. They generally take 1-2 days to respond to emails. This is your basic import quality stuff. I've bought a few things from them and I've been quite happy with them. Definitely a good deal for the hobbyist. Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Tue, 2 Dec 2003 20:19:02 -1000 (HST) From: Tom Benedict Subject: Re: 2 inch travel dial indicators I picked mine up from Enco. They were in the monthly specials flyer that month for something like $29 apiece. I've seen the same ones go as low as $25 in the Enco and MSC flyers. Normally I love to surround myself with as many things that say "Starrett", "Mitutoyo", "Brown & Sharpe", etc. Ok, mostly in my dreams, but that's beside the point. I realized these indicators would see some atrocious vibration and opted to pick up some cheap ones in case they broke after a week of heavy use. They've been on for a couple of years and still haven't died. Even so, I'm glad I went the no-name route. At some point I'll break 'em and I imagine they'll make the same noise a Starrett indicator would. Only I won't have to cry as much. Tom ------- Date: Sat, 31 Jan 2004 12:54:47 -0500 From: Stephen Brown Subject: Re: Digest Number 1430: Small shank wiggler source? >Date: Sat, 31 Jan 2004 From: Jonathan Burchmore >Subject: Small shank wiggler source? >A quick search hasn't revealed any 5/16" shank wigglers--does such a >thing exist? Should I just chuck my wiggler up in my lathe and turn >the shank down? Nick Carter (http://www.cartertools.com/) will sell you a edge finder with a 1/4" shank which will fit fine in the small chuck on the Sherline mill. I use the Starret wigglers when milling, because I'm using endmill holders it's quick to swap them, but swapping between an endmill holder and the drill chuck was a nuisance. The 1/4" shank edge finders really speed things up when drilling. Steve Brown ------- Date: Sat, 31 Jan 2004 14:45:39 EST From: DTollenaarx~xxAOL.COM Subject: Re: Digest Number 1430 There are available, edge finders for the Sherline mill. They are made of modified by Fisher Machine. His e-mail address is: Fishermachinex~xxAOL.COM I have purchased 2 of them, and both work well. I believe they cost around $10.00 each. They have a 1/4" shank, and a 3/8" body, so will fit the smaller chuck, collet / endmill holder. Also, compared to my Starrett edge finders for my Bridgeport, they are a little shorter in total length. Good luck Dirk Tollenaar McKinney, TX ------- Date: Wed, 12 May 2004 23:09:35 -1000 (HST) From: benedictx~xxhawaii.rr.com Subject: Re: centering > How do I find the exact center of aluminum roung stock? Is there any > tools or something like that? I need it to be EXACTLY in the center. > I have little room for error. Thanks for your time. Your best bet is to use a test dial indicator. When setting up round stock on a mill, here's how I center the spindle over the part: Mount the part in a V-block that's held in a vise. The hope here is to get it parallel to the spindle. Mount a TDI in the spindle and roughly center it over the part. Touch the tip of the TDI to the part and keep adjusting until you have zero run-out. Lock your axes. You're now centered directly over the spindle. As a second check, lower the spindle and verify with the TDI. If the part is at all tilted it'll show up as an out of center condition. You can do the same sort of trick on a lathe. It's how you center work in a four-jaw. If you don't have a four-jaw chuck you CAN use shims to center the part in a three-jaw. Better yet, use the soft jaws in the three-jaw, chuck up something thin the same diameter as the part you're going to work, and true the jaws. When you chuck the part, the three-jaw chuck should have very little run-out. Again, verify with a TDI. Tom ------- Date: Sun, 16 May 2004 23:45:59 -0700 From: "Dave Hylands" Subject: RE: Re: First project >>You want to find the center height of your tool bit without a gage? Use a pro trick. Just face the end of your piece. If it leaves a nib (small dia.) your toolbit is below center. If it leaves a tapered nib, it is above center. The optimum is dead on center or .003" to .005" below. When you are there, you will leave a nice flat face. You can shim the toolbit to get there, or adjust it with a Quick change toolpost that is adjustable. No matter how much you indicate, sooner or later, you are going to make chips. The results are what count. Regards, Jerry G (Glickstein) << I made a very quick and dirty height gage. I did what Jerry suggests - find the center by observing when the nib goes away. I then took a faced piece of aluminum rod that was about an inch or so high. I put some blue all around the aluminum, and once it dried, I rotated it in a circle with the flat face against the table and the bit touching. You wind up with a line all the way around the aluminum that's at center height. Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Sun, 5 Sep 2004 15:37:28 +0100 From: Clive Foster Subject: Re: Digest Number 1544 [taigtools group] [Discussion of attaching cheap digital calipers to lathe/mill axes.] > What's not to like about the concept? Ed Accuracy and repeatability can be a problem as these DROs are not designed for this sort of use and some of the, perfectly acceptable, design compromises involved in making an inexpensive caliper can lead you into trouble. The potential pitfalls are no great problem provided you know to look out for them. Do remember that the digital output only changes when the encoder counts the next "mark" so there is an inherent error band of at least one mark space, in practice usually considerably more. Check the specs of expensive digital calipers and cheap ones. Headline numbers tend to be very similar but the performance in practice will be very different. A top quality one will do better than its claims pretty much whatever you do to it. A cheapy will only hit the spec if you use it just so. Realistically you will have something like ±5 thou or more absolute error band with an inexpensive device. Using only yours you can obviously work to considerably better than that but you are using it as a comparator not an absolute measuring device. Fine so long as you remember but forgetting can lead to a lot of wasted work (been there). As digital calipers are made to simply close down on the thing to be measured its quite acceptable to have a large hysterisis or dead band before the numbers start changing when you move it. Making things this way helps keep the price down and reduces the risk of errors due to jogging the jaws when you lift it off the component being measured. I've seen up to 20 thou dead band. Fine so long as you remember to slide the caliper straight onto the part being measured but it can be a bit of a surprise if you try and creep up on it. Very bad if you want a cheap DRO. As ever its best to check before you buy especially when dealing with importers rather than factory brands. Same box and nominally same thing may come from different factories so, just 'cos Jack got a good one doesn't mean you will. Personally I'd prefer an analogue dial gauge, especially on the vertical axis, 'cos you can work "between the lines" to much better than the nominal accuracy once you have learnt how your particular one behaves. I have theoretical 1/10 thou reading DROs on my big mill. In practice 1/2 thou is as good as you can work to by the numbers. HTH Clive ------- Date: Sun, 7 Nov 2004 19:40:36 -0600 From: dswrx~xxwebtv.net Subject: Re: Re: wiggler or center finder I have a center finder and have used it to center a point on an odd shaped work piece. The work piece was held in a 4-jaw chuck, and roughly adjusted so the point was close to the lathe's center. I mounted the center finder in the tailstock chuck and brought the point so that it is pressed on the point of work piece. Then I used a dial indicator to indicate on the "ball" of the center finder. By rotating the workpiece, the jaws of the chuck were adjusted until the indicator showed that the point was centered. However, I use the center finder more on my drill press. Leo (pearland, tx) ------- Date: Sunday, December 12, 2004 6:01 PM From: Jerry G Subject: Re: [sherline] Digest Number 1765 Original Message ----- From: Gdavis5000x~xxaol.com >>Jerry G- You mentioned checking out a precision square using a good DTI. Can you shed a little light on how to do this? I have an old B$S that was my father's, making it over 75 yrs old, but there are no nicks etc, so maybe it's good. Many thanx for all the wisdom you share on this site. George D << George, I don't know your experience or access to a few items required to do this. You need a good surface plate for a reference. A sturdy surface gage. A really good angle plate.(square to .0001 to .0002" in six inches). A Dial test indicator that reads in .0001"'s ("tenths"). Toolmaker's parallel clamps (pair). Your father's square. Take the square and lightly clamp the beam (the thicker part) to the angle plate face so it is vertical to the surface plate. Do this at the extreme end of the angle plate so you will be able to turn the angle plate on its end. The clamps have to be placed so they extend from the other end of the angle plate. Use a good square to set the edge of the beam perpendicular to the surface plate. With the indicator held in a surface gage, read the edge of the blade and adjust accordingly (gently tap the beam ONLY with a soft mallet or a piece of wood and a hammer, not too large)until the blade is "dead nuts" (toolmaker parlance for no deviation of the indicator needle). Use about .005" of contact with the indicator needle and set it to .0000" for a reference at one end of the blade. When you have that, firmly clamp the beam to the angle plate. Now, set the angle plate on the end. Using the indicator, read the parallelism of the beam edge. Any deviation from "dead nuts" is the accuracy or squareness of the square, of course dependent upon the accuracy of the angle plate. There are cylindrical squares and square calibrating devices but usually beyond the scope of the home machinist. Cleanliness is paramount when checking to close tolerances. Regards, Jerry G P.S. I share in tribute to two really fine toolmakers who taught me when no one else would because they were protecting their livelihood. I understand that now, but resented it then..... ------- Date: Sun, 12 Dec 2004 16:35:10 -0800 From: "Marcus and Eva" Subject: Re: Digest Number 1765 Hi George: Jerry's way of doing this check is the classical way and is very accurate and reliable. Unfortunately it requires some gadgets that are difficult to get hold of unless you've got access to a pretty well equipped inspection department. There is another way however, that's not as good, but still pretty good. It involves the use of a gadget called a cylinder square. The good thing about these is that you can make one yourself cheaply, and they can be very easily checked for squareness with nothing more than a lightbulb. You still need a flat surface, but a machine table will likely do in a pinch. First make your cylinder square: People talk about turning them between centers and fussing endlessly to get them perfectly parallel: none of that is necessary. The cheater trick is to get precision ground barstock about 2" diameter and about 6" long. Chuck an inch or less in the 4 jaw and dial the end close to the chuck in dead nuts. Then mount a steadyrest on the lathe and support the free end. It will run dead nuts because it's supported by the steady...it HAS to run true at that end. Now face off the end and relieve the center so it's sure to stand on the outer rim. Mike the bar at several places to find out how consistent its diameter is. If it's within 0.0002" it'll be pretty good...if not you can easily lap it parallel in half an hour or so with a ringlap and some Clover compound. To check it for squareness, stand it up on its end and place your square against it. Shine your lightbulb from behind, at the line where they're supposed to touch and observe where the gap (if any) is. Now slowly rotate the cylinder square through 180 degrees and touch the edge of the square to it again. If the light gap is in the same place and the same size as before, the cylinder square is accurate. Now you can see whether the square is right angled...if the gap is even from top to bottom it's good. It's not well known, but you can discriminate very fine deviations this way...0.0001" gaps are readily seen when viewed with lighting from behind. As I said, it's NOT as good as doing it properly, but it's a whole lot better than nothing, and if done with care and commonsense, it can be very good indeed...far better than you'll routinely be able to achieve with milling. Hope this helps. Cheers Marcus ------- NOTE TO FILE: The following will be a bit strange for metalworkers that have never even heard of a shooting board, but if you do even a small bit of woodworking the hints are helpful for getting one aligned. A shooting board can be considered a jig to hold a piece of wood so that when a wood plane is run along the jig, the end of the workpiece is planed to exactly 90 degrees to its length. Or by using an angled guide on the jig, the end may be planed to exactly 45 degrees for a mitred joint (think picture frame corner). Or the jig can be modified to give any other angle you want. In a similar way, a jig can be made so that a metal workpiece or vice can be immediately aligned to a specific angle on a mill table. And everyone should appreciate the tip for translating metric measurements, or for that matter any measurements, into another system. ------- Subject: Re: Metric Calculating [oldtools list] From: Andrew Midkiff Date: Thu, 23 Dec 2004 05:30:31 -0800 (PST) Esther Heller wrote: [lots of good info on conversions] As others have said, for bench appliances, no measurements are needed at all. You'll find out once you start using them if they're the right size, too big, too small, too thick, etc. The important thing is to get shooting boards trued up. The way I was taught to true up a shooting board is to put one screw into the part that holds the piece (e.g. 45-degrees). Set it where you think it's true, clamp it tight and shoot two small boards, put them together and check to see if they make a perfect square corner. If they don't adjust and try again. Do this until you have a perfect 90-degree corner and then screw the piece down. It helps if you've already pre-drilled and countersunk the holes in the stop piece. For a 90-degree shooting board, try a butt joint. By using another piece of wood you amplify any small amount it is out of true. If you just try to shoot an angle and then check just the angle with a square, you're not going to see small deviations that will be more noticable when trying to make a frame, for example. Of course, for a bench hook, none of this is necessary since you're not using it for making angled anything. And if you want to quickly convert a measurement of any type while on the web, you can use Google. Just go to Google, and type something like 23 centimeters in inches and you'll get the answer 23 centimeters = 9.05511811 inches. Or even silly ones like 16 tons in troy ounces, 16 tons = 466 666.667 troy ounces. Or speed of light in furlongs per fortnight, the speed of light = 1.8026175 × 1012 furlongs per fortnight. AAAndrew ------- Subject: Re: Metric Calculating From: Nichael Cramer Date: Thu, 23 Dec 2004 09:06:08 -0500 T&J Holloway wrote: > Some years ago in Brazil I snagged a zig-zag rule with inches > along one edge and metric along the other edge. Maybe not very > accurate for either, but adequate for quick and dirty conversions. > Believe it or not, BugBear and other World Galoots, you can't > just walk into any old WW store or Borg Box in the USA and pick yourself > up a metric ruler. We live in a world apart in that regard, it seems, in > the USA, measures in inches, feet, and fractions of same (also acres, > miles, pounds, ounces, quarts, pints, and other archaic W&M). To be fair it's somewhat more muddled than that. The only folks still using non-metric units is the wide populace -- and those who sell to them--, and then mostly for units of length, weight, liquid volume and land area. Most everyone else who regularly use these units, or quantities of other types, has long-since converted to metric (or, at the very least decimal). Growing up, my father would go on a tear if anyone mentioned metric units. Everyone know American Units were the right ones! (Of course, we quickly learned that it was best not to point out that these were actually "English Units" or that as an electrician, he himself was perfectly happy using watts, volts, ohms, etc. -- all proper metric units). On the other hand, my mother ran the critical care unit at the local county hospital. Even there, in rural central Indiana, they were using metric units (CC's; liters of fluid; weights of patients in kg; etc) for as long as I've been aware of such things. Even among those who stick to English units, most have decimalized the units. When we go to the gas station, the pumps report not pints and quarts but 1/10ths of gallons; odometers on our cars record not furlongs and rods, but 1/10ths of miles. Working on a survey crew with the state highway dept in my college summers, the measuring "chains" were marked not in inches but 10ths of feet. When I buy a packet of lunch meat at the local convenience store, the weight is given in 10ths of pounds, not lbs and oz. So [OT CONTENT:] I guess I'm upholding a proud old tradition with the Stanley 68 1/2 and the Interlox 106 I keep lying here on my desk. N -------- Subject: Re: Metric Calculating From: Nichael Cramer Date: Thu, 23 Dec 2004 09:31:59 -0500 Dan Indrigo wrote: >Actually temperature conversion is fairly simple. Take the temperature in >Celsius, double it and subtract 10%.[..] This is so much simpler for those of us who remember Bob and Doug MacKenzie. To convert from metric just multiply by 2 and add 30, eh. So 25 dg C is (2 x 25) + 30 = 80 dg F. A metric six pack becomes (2 x 6) + 30 = 42 beers. etc. Simple, eh? ------- Date: Mon, 4 Apr 2005 19:35:20 -0700 From: "Bob May" Subject: Re: Re: Checking the accuracy of a level... [atlas_craftsman] If you want a flat plate, look up how to grind a flat on my website. It will make a very flat plate without testing and is fairly easy to do. I'd make sure tho that you use a thickness to diameter ratio of no more than 1:20 (1:10 would be better) and then suppport that glass with a 3 point system for max flatness. Bob May http://nav.to/bobmay http://bobmay.astronomy.net ------- Date: Sun, 08 Jan 2006 12:05:45 +0000 From: Steve Blackmore Subject: Re: Zero backlash - Possible ?? [taigtools] On Sun, 08 Jan 2006, you wrote: >I started to check my backlash and it seems that my backlash is Zero >in all 3 axis. >It's without software, i.e., software backlash is zero too. >My indicator can read 0.0004". >Is it possible that my mill has zero backlash in all three axis? >Or am I doing something wrong, or my indicator is wrong? Zero backlash is impossible, the screw would need to be locked solid ;) >Here is what I did: >I attached my magnetic holder to the table or the motor, touched one >of the axis with the indicator, and zeroed the indicator. Then moved >the axis in 1" or 2" and brought it back to zero. The indictor showed >zero backlash in all three axis. Backlash only shows up on a change of direction. By moving in, touching off and moving away then back you took up any backlash, all you have proved is it's possible to get back to the same place. You need to measure the distance traveled, how do you know you "really" moved exactly one or two inches? Using a dial gauge, move the table left to right, position the dial gauge against the spindle so it's depressed in over half an inch and zero the dial indicator. Now move in the opposite direction .5" either by commanding G0X0.5 or turning the hand wheel .5" as indicated on the hand wheel, - does the indicator measure .5?? Probably not. That is the backlash at that point on the screw. You will find it varies along the screw a bit. Machine deflection also has a bearing on accuracy. Touch off against the spindle and push the table, how much deflection do you get? This shows gib wear, bending, screw backlash etc all of which have an effect on accuracy. Don't be discouraged when you see the amount of deflection, even on big commercial machines you can see movements on the dial when you lean on the table. Steve Blackmore ------- Date: Sun, 08 Jan 2006 15:58:10 +0000 From: Steve Blackmore Subject: Re: Re: Zero backlash - Possible ?? >>does the indicator measure .5?? Probably not >If I depress the Gauge 0.5" to the right, then go 0.5" to the left >shouldn't I read zero in the indicator not 0.5" as you mentioned? Depends which side of the spindle you put the dial on ;) Steve Blackmore ------- NOTE TO FILE: This above backlash discussion is complicated by the use of a computer program to move a CNC-operated mill. Apparent backlash can appear to be near zero because the computer software is normally set up to eliminate backlash. If the computer knows where it starts, and where it is at all times, then to get to any location it can compensate for any "backlash" (think looseness in the screw mechanism that moves the table or mill head) by moving past the slop (screw looseness during the direction reversal) and getting to the location it was told to find. The computer (or a DRO or dial/digital indicator monitoring the axis in question) cares about actual location, not the fallible readings on the mill axis handwheel (which only tells you how much you turned this wheel -- not how far the table/head/carriage really moved). There is a lot of backlash discussion in the file "Sherline Mill Backlash" that will prove helpful to understanding backlash and compensating for it on any brand or type of machine. By computer, or manually, on a lathe or mill you can overcome the backlash effect by care in your method of operation. To see backlash on say the x-axis of a manual mill table (or the movement of a lathe carriage along the ways in a similar manner): - move the mill table about an inch left (actual distance is not important = ADINI) and stop; - set the indicator at the left side of the table so it touches the table and reads zero; - continue to move the table left for about a quarter inch (ADINI); - note the current reading on the mill wheel's rotation markings; - watch the indicator as you reverse the table direction -- go slowly; - during the start of turning of the mill x-axis handle, the dial indicator needle (and the table) will not move at all; - when you see the first movement of the dial indicator needle, stop turning the mill x-axis wheel; - look at the difference in rotational markings between where the mill wheel is now, and where it was when you stopped going left; - that difference in the wheel is the slop or backlash that occurs when the table stopped going left, and then started to actually move right. This backlash figure may be different in the other direction. And it will be different for all the axes. And it may be different in future if the lubricant on the leadscrew changes, or the leadscrew gets covered in sawdust or dirt/swarf, or the workshop temperature changes. [Here I have to sympathize with the traditional U.K. machinist in a drafty and barely heated workshop/shed at the bottom of the garden. Brrr! Okay, no hate mail from the one guy with an insulated and heated shop. ;-] To have nearly zero backlash, the screw would have to be so tight it could not move easily. Every machine has some amount of backlash. And our hobbyists' worn ex-industrial machines can have a lot. But we can compensate for any amount of backlash. You need some reading in the other files to see how. Not difficult, just something needing attention. ------- Date: Mon, 30 Jan 2006 14:20:55 -0800 From: Nicholas Carter and Felice Luftschein Subject: Re: Center Finder [taigtools] combelis wrote: > Hi All, I got an edge and center finder. > I know how to find edges, but how do I use the pointy end to find > centers? Thanks, Asi Officially: With the spindle spinning, push the tip of the centerfinder with a pencil or other stick until it is running true. Then visually align the tip with the point on the work you want under the spindle. Unofficially: You can bring the edgefinder down with the spindle stopped until the tip hits the prick punch on the work where you want the hole (or in a hole if you are trying to align a hole with the spindle). Then move the axis until you no longer feel a ledge between the body of the centerfinder and the tip (use your fingernail). You can also use a mic to measure the width of the body/tip joint, aligned by x and y; if it is over the body diameter then it isn't aligned yet. See our homepage at www.cartertools.com/nfhome.html ------- From: "Jon Elson" elsonx~xxpico-systems.com Date: Wed Apr 12, 2006 6:48pm(PDT) Subject: Re: Measuring Diameter [atlas_craftsman] joegourlay wrote: >Gents, I need to turn a 3.125" diameter cylinder whose diameter is >right on the money. Right now I have a pair of those calipers that >are flat with a little 90 on arm, and round on the other arm. It's >spring loaded so that it will slip over too big a cylinder, with the >spring raising the arm, but the nut keeps it from collapsing on too >small a cylinder. In terms of letting me know when I'm real close, >it's just not cutting the mustard. What kind of (inexpensive) style >caliper is right for this job? A 3-4" micrometer. Fooling around with caliper-type devices always introduces errors. The flat, ground faces of the mike let you know when you have the mike really square on the part, and you can feel the mike slide over the diameter and tell how well it is gauging the diameter. Jon ------- From: "jerdal" jerdalx~xxbrick.net Date: Wed Apr 12, 2006 8:29pm(PDT) Subject: Re: Measuring Diameter As mentioned, a genuine micrometer, in this case a 3-4 size. Best to get decent ones with a meaningful vernier to tenths. One caution, when using the more precise devise, there is always the issue of measuring the "fuzz" from machining. If you need a press fit, or similar close size, and measure "on the money" after turning, chances are it is really under. The "fuzz" and the effect of the turned grooves, etc make it read larger than the actual solid size. It may smash down and loosen. You wouldn't see that with spring calipers, since they simply aren't that precise. For your most-used measuring gizmo, though, and the logical next step from spring calipers and a scale, get a dial caliper. Much looked-down upon by purists, they do give, when properly used and adjusted, a good accurate reading to a thou or two. The 6" size is most handy. Same caveats with respect to measuring fuzz, but dial calipers are good for anything you need to measure quickly and reasonably accurately. If you could only buy one device to add to your spring calipers, a dial caliper is the right thing to get. You will need micrometers for truly accurate measurement to under a thou, but just to cover up to 3" you need 3 mics. One dial caliper gets you over that range for linear, or diametral measurements. For larger diameters than 3", the dial calipers usually don't have long enough jaws. Then you need mics anyhow. For mentioning a dial caliper, I fully expect a good flaming from the purists.... no problem, bring it on. JT ------- From: "Charles Gallo" Charliex~xxTheGallos.com Date: Thu Apr 13, 2006 3:37am(PDT) Subject: Re: Measuring Diameter On 4/12/2006 jerdal wrote: > One caution, when using the more precise devise, there is always > the issue of measuring the "fuzz" from machining. Besides the "fuzz" (aka what surface finish are you expecting) there are a few other issues 1) How level is your lathe? If it's not level, you WILL cut a taper 2) How worn is your lathe? Worn? You'll cut a taper 3) Remember to let your part cool down after cutting, but before measuring - the heat from cutting can, and will affect the diameter. Also, when you say "exactly" 3.125" - HOW exactly is EXACTLY? +- .005 (normal machining tolerance - you're probably looking closer if you're asking "exactly"). +- .001? (Normal fairly tight work) +- .0005 (Now your working to 10ths - have fun, tweak your lathe in before you start) +- .0001 (Hope you have temperature control - let's say it's steel you're working with - its coefficient of expansion is .06-.07%/100 deg c - so a 3.125" will shift .00002 with every degree of change - when working to 10ths - 5 degs will put you out.) Exactly is a VERY inexact word 73 de KG2V ------- From: "jerdal" jerdalx~xxbrick.net Date: Thu Apr 13, 2006 6:03am(PDT) Subject: Re: Measuring Diameter > Besides the "fuzz" affect the diameter Of course, but with appropriate measuring equipment, that will be detected. The issue in hand IS measurement. Matters of technique are a separate issue. JT ------- From: "Jon Elson" elsonx~xxpico-systems.com Date: Thu Apr 13, 2006 9:40am(PDT) Subject: Re: Measuring Diameter > the heat from cutting can, and will affect the diameter Yes, those not familiar with this will get bitten big time when they first need to make something fairly large to exact fit size. Steel expands 7.2 uin/in per degree F. Aluminum is 13! This means a 3.125" part that is heated 20 degrees F will expand 3.125 x 20 x .0000072 = .00045", easily measured with a tenth-reading mike. For aluminum, it would be .0008125. You can do this by holding the part in your hand for one minute! Now, when you get the part smoking hot from a lot of turning, you really need to wait 20 minutes before making the final cut to exact size. Jon ------- From: "n8as1x~xxaol.com" n8as1x~xxaol.com Date: Thu Apr 13, 2006 8:14pm(PDT) Subject: Re: Measuring Diameter jerdalx~xxbrick.net writes: >For mentioning a dial caliper, I fully expect a good flaming from the >purists.... no problem, bring it on. JT i have bushed a dozen or more faceplates/backplates with drive & shrink fits ...dial calipers simply inadequate for such work ...w/ PRACTICE , u CAN feel a thou. w/ spring calipers ..same PRACTICE needed to keep a decent feel w/ dial calipers ,not to mismeasure vernier caliper even better for internal measure as they dont spring to same extent as dial caliper & even tho only to a thou , i thinkl i can read a 1/2 thou . olde tymers routinely made fits w/ spring calipers& testcuts (file). that said ... my 13.95 enco dial caliper gets a lot of use (all bets are off when it hits the cement floor )....(my 3rd one) best wishes docn8as PS best i have found for internal measurement is springloaded gages ..T shaped things ,cant remember their name now ...but u can mismeasure w/ them also ....put in at abt 20deg.angle lightly lock & pull out in one movement,closing it to correct size & REPEAT works better for me than inside mics... ------- Date: Sat Jun 3, 2006 1:25 am (PDT) From: "wthomasx~xxgfn.org" wthomasx~xxgfn.org Subject: Re: How does a edge finder work [Min_Int_Comb_Eng] >>I know how a edge finder works but I can not figure why we need to find the edge of a workpiece. I know how a center hole find works and when to use it but not sure about why we need to find the edge?? Maybe someone could make a example up so I can understand it. Thanks Dale << Hi Dale and All: The purpose of an edge finder is so that you can pick up a straight edge like the solid jaw of your vise when it is set parallel to a mill axis. What the double cylinder type of edge finder does: the top one is chucked in the chuck or collet and the bottom cylinder is moved up close to the work. As the two cylinders are just held together by a light spring the bottom one can spin off center and will do so if touched lightly with a finger. Now move the bottom cylinder towards the solid jaw as you spin the spindle at 200-400 RPM and watch the oscillation of the bottom cylinder decrease until it stops oscillating. Now watch the bottom cylinder as you move the vice in really small increments (.0005 or so) and it will slide off to one side of center. Stop and set your dial at one half the diameter of the edge finder barrel in the direction that you would reach zero if you continued to move toward the jaw. Now double check by going back and bringing the edge finder right up close (within .005 or .010) to the number you set the dial at but not all the way. Now creep up slowly and watch the edge finder as it may slide off center a .001 or .002 before it did last time, if you were moving too fast. When you are able to go up to the part face two or three times and have the same dial setting you know that you have the correct position of the jaw edge. After you get good at it, you can do it in one try and then just check once to be sure you are right. Clear as Mud? Let me know what you don't understand if you didn't understand and I will try again. GOD'S BLESSINGS Bill ------- Date: Sun Jun 4, 2006 12:10 am (PDT) From: "wthomasx~xxgfn.org" wthomasx~xxgfn.org Subject: Re: How does a edge finder work > How would you proceed to machine a part if the key dimensions were > from an edge or a corner instead of being centered in the part? HI Julian and All: To machine from an edge or corner of a part, you would set the part up on the machine with the edge you need to work from parallel to one of the axes. If the two edges you are working to are square to each other then the second side will also be parallel to the opposite axis. Now pick up each edge with the edge finder in each axis square to the edge you are working to. Be sure to set the axis dial one half the diameter of the edge finder off from zero or move it (the edge finder) one half the edge finder diameter so the center of it is right over the edge of the part your are working to and then reset the dial for zero. Do this for both axes and move to the corner of the two edges. The two axes' dials should read zero and the edge finder should be centered right over the corner. Now remove the edge finder and insert a small drill like a 1/8 inch. Next make the correct distance move from each edge. Now bring the drill down close to the work and rotate it so the web of the drill is parallel to one of the edges you are working to. You are now ready to check your moves with a scale by measuring from each edge to the web of the drill. You should be able to measure to within .005 or .010 of an inch. Clear as mud?? If you can't screen it let me know what you don't understand and I will try and thin the mud with some more water. GOD'S BLESSINGS Bill ------- Date: Sat Jun 3, 2006 8:02 am (PDT) From: "Larryg" lnjgalvinx~xxproaxis.com Subject: Re: How does a edge finder work Dale: A lot of drawings locate features from a corner of the face or edge of the material. If the drawing has a bunch of holes that are referenced to a corner of the face, then use the edge to find the two edges that coincide with the 0,0 point on the drawing. Lift the spindle and move 1/2 the diameter of the edge finder so that the center if the edge finder is above the edge and zero out your DRO or dials; and when you move to 0,0 on the readout, your spindle center will be located just above the intersection of the two edges just located. Now all you have to do is move the table to the location of the hole as called out on the drawing, and use the DRO or dials, whichever you have, to confirm that you now have the spindle located just above the point you want to drill. No measuring or laying out the locations of the holes on the bench, and then trying to locate each position by sight. Lg ------- Date: Sun Jun 4, 2006 8:41 am (PDT) From: "Larryg" lnjgalvinx~xxproaxis.com Subject: Re: How does a edge finder work Ah Ha In another post Frank said " first I set the zero position for the cross feed on the fixed jaw of the vise," Then Julian comes along and says "To machine from an edge or corner of a part you would set the part up on the machine with the edge you need to work from parallel to one of the axis." Both of the above statements are true, in my mind, but point out something to me that also has to happen. In Frank's case you have to know that your vise is set up correctly. That being you have to have the fixed jaw parallel to one axis of the machine table travel. This setup of the vise should be SOP but this explains why. Lg ------- Date: Sun Jun 4, 2006 10:15 am (PDT) From: "Frank Hasieber" fhasieberx~xxyahoo.co.uk Subject: Re: How does a edge finder work Ah Ha OK an explanation is due! I guess I now just take it for granted as I have had it for so long, I didn't think about it. I have a key attached to the bottom of my vise that is a good push fit into the table slots. To do this I first made the key a good fit in the table slot; then clamped this key in the vise with about half of it above the vise jaws; then took the vise, turned it upside down with the key in a slot and clamped the vise to the table; then machined a groove about 3mm / 1/8" deep which is parallel to the table slots and the width to take the key. The key is attached with 2 countersink caphead screws. By doing this you can be sure the fixed jaw of the vise is always truly aligned to the table. Sorry, I hope this helps. Frank. ------- Date: Sat Jun 3, 2006 12:11 pm (PDT) From: "Carl Carlsen" kd7bfnx~xxearthlink.net Subject: Re: How does a edge finder work For a good explanation of an edge finder, take a look at: http://www.metalwebnews.com/howto/edge/edgefind.html While you are there, take a look at the wiggler: http://www.metalwebnews.com/howto/wiggler/wiggler.html Both explanations are written by Mike Rehmus, editor of the Model Engine Builder magazine. Good information. Carl ------- Machinest's Level question [atlas_craftsman] Posted by: "John Sawicky" john.sawickyx~xxncpa.com Date: Fri Aug 18, 2006 5:13 pm (PDT) I was looking out on Amazon and they have both the Starret levels (4, 6 and 12") that are rated to .005" per 12" and Grizzly levels (6 and 12") rated at .0005" per 10". Is that possible? Anyone with experience with Grizzly levels? They are half the price. Thanks, John ------- Re: Machinest's Level question Posted by: "Jim Bosley" bosleyjr04x~xxyahoo.com Date: Fri Aug 18, 2006 6:39 pm (PDT) John: Don't have to tell you that you are paying a luxury tax for the finish, country of origin, and construction quality of the Starrett. That said, I bought an older Starrett (series 97, shiny enamel finish as opposed to the baked [crinkle] enamel of the series 98) 12 inch. Couldn't be happier with it. The sensitivity is a function of the radius ground or blown into the barrel. Starrett claims that ground (the method that they use) is 4 times more sensitive to movement than plain vials. I would guess that the Starret is more repeatable because of a more accurate and smoother internal vial finish (allowing finer and more repeatable readings). You can buy Starrett "Master Precision" 12 inch levels that have the 0.0005 inch per 10" sensitivity, but they are several hundred bucks even on epay and $625 on Amazon. I think some of the old ones have hand scraped bottoms! The normal 0.005 inch sensitivity in my unit was certainly enough to level my table saw and lathe table. Not sure, for smaller lathes like my 10 inch Atlas, I have to think that the normal machinist's levels are adequate. To give you an idea, I got my table saw leveled, and then got readings showing some tilt. All I had to do was wipe the dust off the level bottom and the table and the table was true again. So even at 0.005 per 10, dust was a factor. So do you need 0.0005 inch per 10 inch sensitivity? I'm guessing possibly yes for a LeBlond 22 inch or a 90 inch gap bed. Probably no for your 9 inch South Bend? Comments from the experts? Jim ------- Re: Machinest's Level question Posted by: "jerdal" jerdalx~xxbrick.net Date: Fri Aug 18, 2006 6:51 pm (PDT) > Is that possible? Anyone with experience with Grizzly levels? They > are half the price. Yes, Bought one, sent it back for full refund. It didn't read right, very inconsistent..... I checked it on my granite flat. Three out of four corners touched at once...... the center of the base didn't at all. It was a banana. No wonder it didn't read right for me. I could have scraped it in, but that really wasn't my job. I got enough projects. I sent it back, they were decent enough to refund shipping both ways. Hey go ahead and buy one... you might get the one I sent back! JT ------- Re: Machinest's Level question Posted by: "Mario L Vitale" mariol.vitalex~xxatt.net Date: Sat Aug 19, 2006 8:14 am (PDT) > So, why would I need my lathe bed to be so level? BR Bob - St. Louis Bob, I may be wrong, but "leveling" is not the real intent. What you are trying to do is to assure that there is no "twist" in the bed. Obviously, if you can get one end "dead level", you now have a good, simple reference plane to check the other end to. With regard to the required accuracy, it depends on whether you ever cut any constant diameters longer than a few inches or not. It doesn't take much twist to create a significant taper over, say 20". Mario ------- Re: Machinest's Level question Posted by: "Dave Clements" clementsx~xxla-tierra.com Date: Sun Aug 20, 2006 6:57 am (PDT) When I set-up my 12" last year I couldn't find my level so I shot a spot on the wall about 12' away with my laser level and marked it with a pencil then moved to the other end of the ways and shimmed until there was no difference. When I found who had my level ( first bowerer lent it to a friend through 5 people) there was no measurable difference in the laser level setup and my Starrett. Dave Clements Sport Scouts & Antique Electronics ------- Re: Machinest's Level question Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Sun Aug 20, 2006 10:39 am (PDT) The laser level has the potential to make it more accurate than any regular level because by shooting a spot far away you have effectively amplified any error in level. A small movement of the level will show a large movement on the wall. I did this once while levelling a garage door. Not owning a level longer than 24", I knew that if I took a regular level all I would see was the wavy pattern on the bottom of the door, which was significant. I shot the laser onto the back wall of the garage and leveled from there. Worked great. Michael ------- Re: Machinest's Level question Posted by: "Bob May" bobmayx~xxnethere.com Date: Mon Aug 21, 2006 2:02 pm (PDT) Actually, the absolute accuracy of the level isn't needed. What is needed is to have a good flat surface on which the level sits so that moving it about won't change the indication. Probably the best way to do the testing is to put a mirror as far away as you can and reflect the laser back near you and first test the laser for pointing accuracy sitting on the lathe bed (move it back and forth across the bed so that you can see if the base is concave/convex or is indeed flat). After doing that, moving the laser down the length of the bed will indicate whether the bed itself is flat. You should be able to hold the point of the laser to about 0.010" or so and that would be about 1/4 of a thou at 40' of distance out and back for the beam. Additional reflections can produce even more accuracy with the level. Bob May http: slash /nav.to slash bobmay http: slash /bobmay dot astronomy.net ------- Re: Machinest's Level question Posted by: "Dave Clements" clementsx~xxla-tierra.com Date: Mon Aug 21, 2006 11:13 pm (PDT) [as to the accuracy of a carpenter level versus using a laser] Think about what you are saying. The accuracy of the level is totally inconsequential the only thing that matters is that the laser shoots at the same angle from the ways. think of it as a very long straightedge. Same principal as the old Light align front end machines that were more accurate than todays computer aligners. It checked exactly the same as the Starrett. Dave Clements Sport Scouts & Antique Electronics ------- Leveling a lathe Posted by: "Rex" rexarinox~xxgmail.com Date: Mon Aug 21, 2006 10:20 pm (PDT) Every time I see the conflicting stories about leveling a lathe and how expensive a device one needs to "get it right", I have a hard time not posting my own experience. I wanted to level my lathe. I collected all my carpenters levels, and set each, in turn, on the lathe bed near the headstock. I have a thin shim, .oo3", and I put it under one end of each level. I picked the level that had the greatest movement in the bubble. With a magic marker, I marked the bubble, and the limits of where the level set on the lathe bed. I moved to the other end and set the level in the same relative position, and adjusted the bed so the bubble was as near as possible to the same place. The lathe is now more accurate than I am, so... Try your own levels with a thin shim under one end. I'll bet it will be easy to see the variation in a laser dot projected on a mirror and reflected back to the wall in front of you, and some cheap levels will also be useful. If neither approach works for you, make your own level. Start with a small diameter glass tube from a chem supply, about 4 inches long, seal one end, add colored water that has sat around long enough to de-aerate, and seal the other end, leaving a bubble. Clamp each end of the tube to the flattest bar stock you have and stick a .001"-.005" shim in the middle to impart a curve to the glass - voila, instant level. Set it on a flat surface that you have leveled to the best of your ability with other equipment. Verify that your level/barstock is flat, and see if the bubble is repeatable - does it read the same all over the surface? Does it read the same if you turn it around? If not, your new "level" can only be used in one orientation. Does it show a difference if you raise one end a few thousandths? If not, your level isn't accurate enough, so try using a thinner shim in the center, use a flatter bar, etc. There probably isn't enough info here to build a level if you can't work from a concept, but there may be enough encouragement to build a level if it makes sense. Remember, you don't care about true level, you just want both ends of the lathe bed to show the same reading on a device that will show small variations in comparative level. rexarino ------- NOTE TO FILE: There are discussions in the Atlas Repair or Fitting file as to how to use machinist precision levels to set up a lathe (brand of lathe does not matter). In 2007 the following message gave some good instructions on ensuring that a "precision" level really is precise. ------- Re: Question on Precision Levels [atlas_craftsman] Posted by: "helpx~xx4mtool.com" Date: Sat Feb 3, 2007 8:30 am ((PST)) To check (or self calibrate) your level, place the level on the most level surface you can find- a leveled granite surface plate would be best, but a suitable (level) countertop or glass would do. Place your level on a spot where your level reads zero. Rotate the level 180 degrees by pushing on one corner of the level. If your surface is flat, this should pivot in the center. If it does not, your surface plate or level has a high spot. When the level is rotated correctly in place, read the bubble division on the level again. If it is the same as in the original position, your level will read the stated accuracy. If it is not, adjust approximately half the difference of the error. When you can get identical readings in both directions, your self calibration is done. Adjustment is done (on most levels) by a spring loaded screw at one end of the spirit tube. The other responders have given you good advise on the lathe leveling. Regards, George O'Connor georgex~xx4mtool.com ------- NOTE TO FILE: The following conversation was part of a much longer thread on tramming a mill (measuring the perpendicularity of the mill spindle with respect to the table, and then adjusting the mill if found to be out of alignment). See the Sherline group archives for March 2007. There are other tramming/alignment conversations in the Sherline and Taig mill files on my site. ------- Re: ease of tramming [sherline] Posted by: "David Clark" dcclark111x~xxcomcast.net Date: Mon Mar 12, 2007 7:10 am ((PDT)) In sherlinex~xxyahoogroups.com, "Alan Haisley" wrote: > do you unload the tension on the DTI to prevent jarring the bearings or > is that unnecessary? Hi Alan: When making any adjustment with a DTI, it's essential to have it in contact with whatever you're adjusting so that you can read it while you're moving things. Otherwise it really would be blind tap and try, next to impossible. I wonder if that's the difficulty some are having? I've never seen an indicator harmed by doing this. I'm talking about really gentle taps. My favorite adjuster is a brass hammer with a head that weighs about 3 ounces (85 grams), 5/8" diameter, 2" long. Hardest I ever hit anything during adjustments is about the force of dropping this hammer a few inches. Things should be just tight enough that such a blow moves the adjustment a few thousandths of an inch. Thanks for the question, I hope this clarifies things. DC (OK, I just remembered one incidence of a jarring problem: guy left an indicator in the spindle and turned on the mill. Slapped against a mill vise at 1000rpm, threw the pieces across the room. That was a severe jarring, the indicator was never the same.) ------- Re: ease of tramming Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Mon Mar 12, 2007 7:24 am ((PDT)) Hi David C., and Alan H, I like to pre-load my DTI no more than .005" when making such adjustments. I too witnessed such a "jarring" experience. Which is why I unplug my machine when making adjustments. Jerry G (Glickstein) ------- Re: ease of tramming Posted by: "campchair" goboomx~xxbellsouth.net Date: Mon Mar 12, 2007 5:17 pm ((PDT)) Hi all: As an old burnt-out machinist, I personally have "scrambled" an indicator or two by leaving it in contact when tapping with a lead.brass/ rubber/fiber hammer. It's the shock. If it is a very high quality one, with jeweled movements, the vibration is certainly not good for it. I have PERSONALLY cracked a jewel or 2. (I know it says "shockproof", but....). If you have a chance, under very clean conditions, remove the 4 screws at the back and peek inside sometime. Q: Would you knowingly tap on the side of a spring-powered watch? As you can see, the gears are very similar in precision. And, while you are at it, take a cotton swab moistened with tech. grade acetone or pure ehtyl alcohol and clean up the mechanism. (Keep off the face, it may dissolve - likewise the "Crystal"; it will fog.) Re-lube with watch oil applied to the moving parts VERY SPARINGLY. (Dirt and/or abrasive chips are good as lapping compound and will destroy the accuracy in a short time.) I store all mine under cover when I'm not actively using them. Till I learned, I ruined several through neglect and shock. Since then, I have some that are 30+ years old. (One Federal Dial is, I know 30 yrs.+++ - and it was old when I got it! Still good and in daily use.) The dropping of the plunger is not very good for the gears and the rack engagement. I just always lift the plunger before tapping anything like either a "Besttest" or a dial indicator. Bill the Gunsmith ------- Re: ease of tramming Posted by: "David Clark" dcclark111x~xxcomcast.net Date: Mon Mar 12, 2007 6:46 pm ((PDT)) Hi Bill: Thanks for your input. In every other case I can think of, when I'm tapping something into position while monitoring the movement with an indicator, the indicator is attached to something other than the thing I'm tapping. The exception is the way I tram the mill. There are 2 types of indicators differing by their actuators: plunger type and lever type. It's my understanding that the plunger type is a good deal more robust. As you know, they're routinely used, permanently attached to machine tools, as positional readouts. There, they are subject to quite a lot of shock and vibration, not to mention dirt, oil, chips, and all the other detritus of machining. This is the type I'm using and recommending for adjusting the tram. See my posted photos. I would probably not do it with a lever type. Those I treat will all the tender care you suggest. The indicators I use every day (both types) were new when my father was an apprentice, and have been in regular use for over 70 years. I fully expect them to last another few generations. BTW, I've often refurbished indicators and other instruments as you describe with excellent results. Best regards, DC ------- ease of tramming (was: [sherline] Re: NEW PHOTO NOTICE! FOR MILL Posted by: "campchair" goboomx~xxbellsouth.net Date: Wed Mar 14, 2007 4:29 am ((PDT)) On 3/10/07, Kevin Martin wrote: > >Although *testing* the tram this way is easy, I have yet to find > >any way of *adjusting* the tram. It seems to be a > >hit-and-miss process of "too high on the right... > >Loosen the clamp a little (enough, but not too much!), > >thump head to turn it CCW a bit, tighten clamp, test again... > >Drat now it's too high on the left". Kind of reminds me of the > >way I putt in golf... > >This is true of all the other squaring-up adjustments too (column > >vertical, for instance). Although you may know it is so many > >thou/degrees out of alignment, there is no reliable way of > >adjusting it by even *approximately* that amount. Kevin Martin "Pierre Coueffin" wrote: > When I get tired of making fine adjustments with a sledgehammer, I > usually switch to a lever or install a fixture that I can set up some > sort of screw-jack with... Try this: Get a piece of ground drill rod, as long as possible to fit from the spindle nose to the table. Check it to make sure there is very minimal taper or ovalness. It MUST be as true as possible, OD and TIR for this to work. Choose a size that is as big in diameter that your collet will handle. (I use a 12" long piece of 7/8" ground Starrett O1.) Center the spindle, and insert the rod as far as possible into the collet. Do not install in a drill chuck; they are seldom really true. Tighten it snug and make sure it is true in the collet. (Use your indicator, spin it over by hand, it probably WON'T be that true.) Lift the indicator spindle when you tap it. This CAN be done under slow {200 RPM or so power if you are careful....VERY careful.) Now, stop the spindle. Take your 4" or 6" Machinist's square (Don't have one? Good excuse to buy one!) Make sure the table is clean and deburred. Place the thick side squarely on the table. Hold it down. Slide it up against the drill rod. Place a strong lamp behind it. Adjust the head in ONE axis. (Fore & Aft, or L&R, choose, but only one at a time.) Once you can see no light, dog it down, then go to the other axis. When all the light is hidden, check all 4 sides. Then, switch to the "Last Word". It actually takes less time to do this than to write it up, and you'll be pleasntly surprised how close you are and just how quickly tramming a head can be done. "Don't cut with a Dull Tool, Bill the Gunsmith ------- Re: ease of tramming (was: [sherline] Re: NEW PHOTO NOTICE! FOR MILL Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Wed Mar 14, 2007 4:37 am ((PDT)) Hi Bill: What mill are you talking about? A 7/8" collet sort of leaves the Sherline in the dust! :) Later, Jerry G (Glickstein) ------- Re: [SPAM] Re: ease of tramming (was: [sherline] Re: NEW PHOTO NOTIC Posted by: "William Wood" goboomx~xxbellsouth.net Date: Wed Mar 14, 2007 4:11 pm ((PDT)) Sorry, Jerry, Most of my experience is either with a B&S with the Universal head or with a Bridgeport---I was looking at a Sherline as an alternate to use for small jobs in the gunshop when my "Big Momma" was tied up. Plus, I'm starting to do a lot of very small milling and lathe work on items like Express Sights and the accompanying flip-up Night Sight for the front. Someone suggested I look into the Sherline and I found this site. I didn't know the capacity till I actually pulled up the company website---But, I'm still thinking about getting one. BTW- in your experience, what depths of cut can the lathe usually handle, say on drill rod. Something like a .500" od O1 workpiece, with a suitable insert tooling. ? I know they are both benchtop machines (I can tell it isn't a Monarch EE !!) but many, many jobs I do are very, very small, like watch-sized parts. I was thinking it would complement my bigger machines very well. Also, - the method I described DOES work just reduce the OD of the rod. 3/8" works well, too. (Whatever will fit and be steady.) Saves a lot of time on something like the Universal head on the B&S. It'll get you in the ballpark a lot quicker and with less headache. It looks like it really would save a lot of time on the Sherline mill. Bill (WOOD'S GUN REPAIR SERVICE) ------- Re: [SPAM] Re: ease of tramming (was: [sherline] Re: NEW PHOTO NOTIC Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Wed Mar 14, 2007 7:55 pm ((PDT)) Hi Bill: No problem... I have had a lot of experience(s) with all the full size lathes and mills to be found in industry... The Sherline mills are fine, but do fall into the class of mini machines and must be treated accordingly. Take a lot of fine cuts and you will get there. I have the 4000 short bed lathe and the 4400 long bed lathe. The 5000 mill and the 2000 mill ... all Sherline. I personally like the following for "tramming". I have a very accurate large ball bearing outer race that bridges the slots on the table. And I like the small "Indicol" holder for my DTI. My favorite DTI is the 312B Interapid. Jerry G (Glickstein) ------- Re: Electronic calipers as DRO [atlas_craftsman] Posted by: "Rexarino" rexarinox~xxgmail.com Date: Tue Apr 17, 2007 3:39 pm ((PDT)) On 4/17/07, lotustonyclark wrote: > I've searched the files and photos but can't find anything on mounting > cheap Harbor Freight-type electronic calipers for use as DRO x & y > readout units on small lathes . . Can anyone direct me? This group is all about building a DRO for any lathe or mill from a few components and some cheap digital scales: http://groups.yahoo.com/group/ShumaTech/ The archives of this group have numerous discussions and the files and picture section should give you good ideas. Google YADRO for another option... Another Yahoo group has copious information on DRO's http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/ That should give you some reading. rexarino ------- Re: DRO on X & Y axes [atlas618lathe] Posted by: "MikeA" mandrex~xxen.com Date: Sat Apr 21, 2007 2:53 pm ((PDT)) > There are a few pictures of my multi-purpose carriage stop as well. > This item clamps onto the front way and has two 1/4" holes for drill > rod. I have a bracket that will hold a DI which I put into the stop > through the lower hole. I can then measure carriage movement. Usually, > I will determine a stop point, lower the DI out of the way, and then > run a rod through the upper hole and clamp it as a stop. > > When I'm drilling deep, I use the carriage stop in a different way. I > have a part that allows me to connect the tailstock to the carriage, > so I can move the drill bit in and out with ease. I set the stop using > the upper hole in the carriage stop bracket and the run a loose rod in > the lower hole. It moves in with each drill peck, so when I come back > in I can see how far I've gotten. > > These things may be a bit crude, but they work very well for me. -Bruno Hello Bruno: I'm working on the mounts for the carriage dial indicator as shown in your photos but I'm a bit hung up on the bracket for the indicator. Did you cut off the lug on the back of the indicator? I'd also like to see your connector for the tailstock to the carriage if you don't mind. Your solutions are really quite elegant, certainly far from crude! Hate to impose, but would you take some more photos showing the mounting of the dial indicator? All the best, Mike ------- Re: DRO on X & Y axes Posted by: "azbruno" azbrunox~xxyahoo.com Date: Sat Apr 21, 2007 6:14 pm ((PDT)) Mike, I've attached more photos. There is a separate bracket that holds the DI to be used with the carriage stop. The biggest problem I had was that the lathe is so small that I had to measure everything 12 ways to make sure I could get things to fit. While this may not be the most elegant solution, it does allow me to set things up fast. The long 1/4" rod holding the DI can be adjusted in the carriage stop (lower hole) to give a long range of measurement without too much difficulty. I would like to attach a small plate to the contact point on the carriage so it's flat to the DI. There are also some pictures of the bracket to link the tailstock to the carriage. This was one of the first things I did and is very crude, especially since it's made to fit on rough castings. The two thumbscrews on the top are just to keep the part from twisting a bit, and the two on the sides tighten it against the front of the carriage and back of the tailstock. Notice that each end part is held to the cross piece with two setscrews. The outermost setscrew on the front piece (towards headstock) is unscrewed to allow that piece to swivel up so it can be installed. Anyway, it does the job in that I can use the carriage crank to drill in. I do push from the back, though, to keep undue stress off the rack and pinion gearing. Using these tools, here's how I do precise drilling depth. I have a small part (not pictured) that fits into the top hole of the carriage stop and protrudes exactly .100". So say I want to drill 4" deep. I put the long drill rod into the top hole of the carriage stop and measure out exactly 4.100" using my caliper. With the tip of the drill bit at my 0 point, I attach the carriage stop so the drill rod abuts the carriage. Then I remove the drill rod from the top hole and put it into the bottom hole, but don't tighten it down. And I put the small stop part in the top hole. The top part is the stop. The drill rod in the bottom is left to float so as I drill in, it's always showing me how far I've gone, since it's being pushed by the carriage. I need this because I drill deep in plastic and need to bring the bit out a lot to cool and remove chips. And I need to go in slow so it's good to know where the bit will hit the material. Hope this helps. Bruno ------- Re: DRO on X & Y axes Posted by: "MikeA" mandrex~xxen.com Date: Sun Apr 22, 2007 5:18 am ((PDT)) Hello Bruno: Thanks a million for the additional shots - these will help immeasurably! As you comment, there isn't a lot of room for 'slack' on these lathes, and the first couple attempts I made at the DI mount came up a bit too big in one dimension or another. I like the idea of attaching a flat contact on the carriage, but what I've done is buy an extra carriage and X-slide (just a bit nervous about drilling and tapping holes in my lathe!) that will be used for any modifications I make, and I'm thinking of milling a flat on the side of the carriage. Once I get the DI done then I'll work on the connector for the TS and carriage - looks like a good solution! Once again, thanks for sharing all this information. > There is a separate bracket that holds the DI to be used with the > carriage stop. The biggest problem I had was that the lathe is so > small that I had to measure everything 12 ways to make sure I could > get things to fit. The long 1/4" rod holding the DI can be adjusted in the carriage stop (lower hole) to give a long range of measurement without too much difficulty. I would like to attach a small plate to the contact point on the carriage so it's flat to the DI. All the best, Mike ------- Re: DRO on X & Y axes Posted by: "azbruno" azbrunox~xxyahoo.com Date: Sun Apr 22, 2007 8:16 am ((PDT)) > ... and I'm thinking of milling a flat on the side of the carriage. Yeah, milling a flat is better. Think I'll do that next time I take the carriage off, now that I have a small mill. > Once I get the DI done then I'll work on the connector for the TS and > carriage - looks like a good solution! I'd prefer to do something more like a trailer hitch. It would probably be easy to affix a permanent bracket to the underside of the carriage and something to the front of the tailstock. The bracket is a bit bulky. On the other hand, I have drawings for a lever tailstock modification that I hope to make some time. But that still limits to 3.5", which is the length of the tailstock ram casting. BTW, if you do the cross slide DI bracket, don't forget to remove the DI before sliding the tailstock up. > Once again, thanks for sharing all this information. You're welcome. Bruno ------- Re: Holding brasss bar [NOW ABOUT INDICATOR USE IN sherline GROUP] Posted by: "Martin Dobbins" trainnutzx~xxyahoo.com Date: Sat May 26, 2007 3:01 pm ((PDT)) Bob Ellis wrote: >Unfortunately, I had only the vaguest idea of how to use a DTI and there were no instructions included. I tried playing about with it, but did not get very far. I looked on the Internet for advice and found nothing. I e-mailed Starrett for help and got no response. So, I put it on one side and just hoped that my lathe and vertical mill were running true. < Bob: Although it refers to Taig equipment rather than Sherline, there are some pictures here which show some ways that a Dial Test Indicator may be used: http://www.cartertools.com/millset3.html There are also instructions for adjusting work in a four jaw chuck here: http://www.cartertools.com/fourjaw.html A Dial Test Indicator could also be used for this instead of the plunger type indicator that is in use. The difference is that The Starrett Last Word is a lever type indicator rather than a plunger type so the indicator setup would have to be changed to reflect this. The Last Word lever will work either way and this is adjusted by a toggle near the dial of the indicator. If you would like to download a video which shows a dial test indictor in use to square up a milling machine, have a look at: http://www.cerritos.edu/nreal/student_grades.htm I would recommend you look at the videos entitled "Mill Head Alignment-X" and "Mill Head Alignment-Y" as a first step. You will see that there are lots of other short videos to look at there too. Hope that helps? Kindest regards, Martin ------- Re: Using a DTI Posted by: "Bob Ellis" bobx~xxbpellis.idps.co.uk Date: Sun May 27, 2007 12:43 pm ((PDT)) Thanks to those who replied with advice about using a DTI. I think I have got the hang of the basics now. It confirmed my suspicions that the Z axis was out of alignment. All I have to do now is make sense of the advice on squaring up the mill that I downloaded from the Sherline website. Reading them through the first time, the instructions didn't make much sense to me, but hopefully they will become clearer when I go through them more carefully. Especial thanks to Martin for drawing my attention to the videos. There are a number of other videos on that site that look as though they will also prove very useful and enlightening. Best wishes, Bob Ellis ------- Re: Holding brasss bar Posted by: "Tom Bank" trbankx~xxpaonline.com Date: Sun May 27, 2007 7:41 pm ((PDT)) Bob: Just don't do what I did! I had my DTI mounted on the mill in a collet, then to "loosen" it I gave the collet drawbar a "gentile" whack. In an instant I had knocked the gears inside the DTI out of alignment and ultimately ruined the little beggar. (I buggered the beggar!) However, at the N.A.M.E.S. show that you probably have read about here, I found a dear little Swiss Compac DTI built back in the '60s that I was able to restore. It is smaller than the one I had, so it fits Sherline equipment better than the one I ruined. Now I need to make one of those things that fit on the top end of the mill spindle that lets you *ease* the drawbar down to loosen collets gracefully. Oh, and as for something to use with your DTI to tram the mill Z column, a neat item that can be picked up cheap -- or even free -- is a platter from a deceased 3.5" hard disk drive. You do have to tear the drive apart and you will likely need some rather small torx screw driver bits in the process (like sizes 10 down to 6). Lay the platter on your mill table and clamp it lightly at opposite edges, then read the DTI as it describes circles on the platter to identify any out of alignment conditions on the Z axis. Regards, Tom Bank -------- vernier question [taigtools] Posted by: "Chris Ghent" cghentx~xxtpg.com.au Date: Mon Jul 30, 2007 1:21 am ((PDT)) I know this is not absolutely on topic, but I have a question about the electronic verniers many of us use as cheap readouts on our gear. I am using one which is a little long, and I would like to cut it down. Does anyone know whether this might mean it will not work..? I understand they work by the readout assessing capacitors built into the paint layer. If the capacitors are in series then perhaps cutting the end off would break the circuit. If tyhey are in parallel it might be OK. Any thoughts..? Chris ------- Re: vernier question Posted by: "Lester Caine" lscesx~xxbtconnect.com Date: Mon Jul 30, 2007 2:05 am ((PDT)) Small grinding wheel will cut them fine. Just take it very slowly and don't allow things to heat up too much. The 'capacitance' is to a printed circuit board mounted on the bar under the cover, and this is just cut to length to fit the metalwork anyway ;) We do it all the time with the readout bars for the DRO350 and YADRO readout's Lester Caine - G8HFL Contact - http://home.lsces.co.uk/lsces/wiki/?page=contact L.S.Caine Electronic Services - http://home.lsces.co.uk MEDW - http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/ Firebird - http://www.firebirdsql.org/index.php ------- Re: vernier question Posted by: "benedict-listx~xxhawaii.rr.com" Date: Mon Jul 30, 2007 12:24 pm ((PDT)) Best bet would be to call the manufacturer. There was an article in HSM or MW a while back where someone was fitting a quill DRO to their mill. It looked like a Mitutoyo, but it's been a while... Anyway, they called and asked about cutting it down, and they were told there shouldn't be a problem. Not saying there wouldn't be a problem, just saying calling the manufacturer got the answer to their question. Tom P.S. No chance of picking up a second set of verniers and keeping the longer ones long? ------- Re: Poor man's DRO? [taigtools] Posted by: "benedict-listx~xxhawaii.rr.com" Date: Thu Aug 2, 2007 4:25 pm ((PDT)) On Thu, 2 Aug 2007, mac_marty_15221 wrote: > Hello, everyone. I'm a complete newbie here, so I hope I'm not treading > over well-plowed earth. Naaah, you never know when plowing a second (or third!) time will turn up something new. > I have a new Taig lathe, and I'd like to add -digital- readouts on all > three axes. I have seen setups by others where they use spring-loaded > dial indicators. I'd rather go digital because I want to be able to > zero out any given axis, and then make a relative move from there. > (Maybe I ought to call this "meat-based CNC"??) I like it! I've been calling it MNC (manual numeric control) but I like meat-based better. One other benefit to digital calipers or scales over dial indicators is that you can switch between metric and imperial at the push of a button. When I did my indicator readout (IRO?) I only made inch parts in my shop. But times change, jobs change, and the place I work now is almost all metric. Having an honest to goodness digital readout would be nice for that, if for no other reason. > I see that electronic digital calipers are very affordable, is this > perhaps one way to go? Are there existing examples out there? (Magazine > articles, websites...??) Or is there some fundamental issue I am > overlooking that makes Indicators a better choice? Nope, nothing obvious in my book. And yes, cheap calipers would be an affordable choice. One caution on calipers that was posted some years ago is that they're only stable when they're stopped. After seeing that post I started looking at max travel speed and readout rates on calipers. Mitutoyo (not "cheap") has some that have no limit to the travel rate and have quite fast readouts. You might look at those numbers when evaluating calipers. Another possibility would be to get some of the less expensive linear readout units that are out there. They show up on Ebay from time to time, though I think Enco sells them now, too. I'd be interested in getting a small quill DRO and chopping it down for my cross-slide, and using a longer linear scale for the lathe bed. For me that's a project for another day. But look around, because others have had the same kinds of ideas, and a number of them have pulled it off. Check out the photo gallery on http://www.cartertools.com - I'm almost certain there are at least a couple of people who have done something similar to what you're thinking. Tom ------- Re: Poor man's DRO? Posted by: "Martin Dobbins" trainnutzx~xxyahoo.com Date: Thu Aug 2, 2007 5:53 pm ((PDT)) If you have a look at Nick Carter's site as others have suggested, you'll find a goldmine of ideas there. One example that shows what you are thinking of is at: http://www.emachineshop.com/projects/taig-lathe.htm Hope that helps? Regards, Martin ------- Longitudinal position measurement/indication? [atlas618lathe] Posted by: "kyle_doerksen" kylex~xxdoerksen.org Date: Mon Sep 24, 2007 6:04 am ((PDT)) I'm a proud new owner of a 618 and after doing some light rust removal it's time to start making parts. Other lathes that I've used have had either DROs or Trav-a-dials. My 618 so far has neither and also doesn't have a graduated handwheel on the longitudinal/carriage feed. So my question is--how do I accurately cut a feature of a certain length? I would be open to any suggestions as I imagine there are different approaches. Thanks all. ------- Re: Longitudinal position measurement/indication? Posted by: "Lou Balleweg" LouBallewegx~xxearthlink.net Date: Mon Sep 24, 2007 9:13 am ((PDT)) Hi: See the pictures of my Poor Man's DRO in Photo section under the same name. Regards, Lou Balleweg ------- Re: Longitudinal position measurement/indication? Posted by: "george britnell" gbritnellx~xxyahoo.com Date: Mon Sep 24, 2007 2:33 pm ((PDT)) Hi Kyle: Here's what I did on my 618. I made a saddle clamp for the ways and mounted a 1" dial indicator on it. I then made a rectangular post that bolts to my threading indicator that the indicator can bump against. If you go to the following link you can see a couple of pictures. http://smg.photobucket.com/albums/v43/gbritnell/My%20shop/ gbritnell ------- Shop photos of a beautiful Logan lathe and mill drill [atlas618lathe] Posted by: "Hank" n1ltvx~xxyahoo.com Date: Mon Sep 24, 2007 2:52 pm ((PDT)) > I made a saddle clamp for the ways and mounted a 1" dial indicator > on it. > http://smg.photobucket.com/albums/v43/gbritnell/My%20shop/ Thanks, George, for sharing both your method and pictures. Just about everyone on the list will probably enjoy seeing other pictures at the above web address of George's really nice Logan lathe and mill drill. Hank ------- Re: Longitudinal position measurement/indication? Posted by: "Hank" n1ltvx~xxyahoo.com Date: Mon Sep 24, 2007 2:42 pm ((PDT)) Kyle: Please also take a look at Bruno's fixtures for both carriage and cross slide movements under "Bruno's Lathe" in the picture section. Hank ------- Re: Longitudinal position measurement/indication? Posted by: "azbruno" azbrunox~xxyahoo.com Date: Mon Sep 24, 2007 4:14 pm ((PDT)) Thanks, Hank. I was just about to say that. I should say that since making this attachment, I've found new ways to use if. For example, I can stick a piece of 1/4" drill rod in the top hole of the carriage stop and measure out a precise amount up to 6" using a standard dial caliper. I position the tool to the work, and then the stop against the carriage. Then I remove the drill rod. (Actually, I measure .100" high and then replace it with a drill rod that projects exactly .100"). I can use that to set a longitudinal depth of cut up to that length, without using the DI. It's accurate to about a thou. Bruno ------- Re: Longitudinal position measurement/indication? Posted by: "cbrumbelowx~xxcomcast.net" Date: Mon Sep 24, 2007 4:55 pm ((PDT)) Which way do you set up the dial indicator, George? Do you set it to reach zero once you reach the end of the cut...or the other way? Nice goodies on the shelves, BTW. Charles ------- Re: Longitudinal position measurement/indication? Posted by: "george britnell" gbritnellx~xxyahoo.com Date: Wed Sep 26, 2007 10:46 am ((PDT)) Hi Charles: For short cuts (within 1 inch) I just use the indicator and preload it to some measurement that will give me enough travel to get the dimension that I need. For dimensions longer than 1 inch I use the standards from my micrometer set (1,2,3) to obtain larger spacing. There are many different ways to get dimensions (as others have stated) but this has worked the best for me over the years. It's simple and I can pop it on and off so it's not in the way when I don't need it. By the way, here's another link to my Photobucket account that has some of the work I have done over the years (and most of the turning on the 618 I might add). http://smg.photobucket.com/albums/v43/gbritnell/Modelengines/ gbritnell ------- Re: Longitudinal position measurement/indication? Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Mon Sep 24, 2007 4:55 pm ((PDT)) You can also use a Mighty Mag magnetic base attached to the ways with a dial indicator. I've always used these on larger lathes, and I just finished building an attachment for one for use on my 12" Atlas. I'll probably build a smaller version for my 618 in a few weeks. The attachment is needed because the Mighty Mag clamps on the top of the ways, but the bearing surface on the carriage is below and to the front of the where the dial indicator tip would fall if just clamped in the Mighty Mag. Michael ------- Fractions to Decimal to Metric [taigtools] Posted by: "stcnc2000" stcncx~xxlycos.com Date: Sun Sep 23, 2007 8:05 am ((PDT)) This Free handy program converts Fractions to Decimal to Metric. Check it out at: http://www.cad2gcode.com/freeprogram Cheers Bob A ------- Reading headstock rpm [MyMyford] Posted by: "novice1943nl" j.roos12x~xxchello.nl Date: Thu Oct 25, 2007 6:56 am ((PDT)) Hi all, some time ago I was able to connect an inverter to my S7 and run the lathe on 3-phase supply. This implies that I can change the spindle speed with a variable resistor in a very wide range. The disadvantage is that I do not know the speed after touching the resistor's knob. Is there anybody who has knowledge about a SIMPLE device to read the rpm continuously in a kind of display. I know of an article in ME or MEW about such a device but that is a bit too complicated for me. Almost of building a computer. Looking forward to any reaction. Novice ------- Re: Reading headstock rpm Posted by: "Ken Strauss" ken.straussx~xxsympatico.ca Date: Thu Oct 25, 2007 7:03 am ((PDT)) You could use a bicycle speedometer to sense a tiny magnet attached to somewhere in the drive train. Optical tachometers are readily available on eBay and from many tool dealers. Alternatively, how about just putting a scale under the knob on the variable resistor? ------- Re: Reading headstock rpm Posted by: "Rich Dean" cmsteamx~xxspeedfactory.net Date: Thu Oct 25, 2007 8:23 am ((PDT)) I did this many a year ago. The bull gear happens to have 60 teeth. Great for dividing, but also figures in as a multiple of an hour. :-)) says I. I duplicated a simple tachometer circuit found somewhere and used the input from a photo transistor placed on one side of the gear and a small lamp on the other all held in a U bracket clipped to the rear of the headstock casting. It's hardly even visible. The circuit output drives a DC needle meter with a homemade scale to show RPM. It works perfectly. RichD ------- Re: Reading headstock rpm Posted by: "HG" hgx~xxallthemunros.com Date: Thu Oct 25, 2007 9:18 am ((PDT)) I'm not convinced it's worth going to much effort at all to discover the actual spindle speeds, and still less to display them constantly. (Though I do accept it could be fun!) I use an inverter on my S7 and I just adjust the speed until it's obviously right for the job. A scale as Ken suggests would enable you to repeat settings that worked before. If you really want to avoid electronics but want to know the spindle speeds for the numbered settings, you could engage/set up a known feed rate and run the lathe for a minute. By measuring the distance the carriage travels in that time you should be able to calculate the spindle rpm -- shouldn't you?!! Then just draw up a chart. Regards, Henry ------- Re: Reading headstock rpm Posted by: "Ken Strauss" ken.straussx~xxsympatico.ca Date: Thu Oct 25, 2007 10:07 am ((PDT)) My VFD (Teco) includes a digital display of its output frequency. I made a table relating frequency/ pulley pair used/ back gear and spindle RPM. But I agree that "feel" is probably a better way of setting the speed. ------- Re: Reading headstock rpm Posted by: "tobybishopx~xxaol.com" tobybishopx~xxaol.com Date: Thu Oct 25, 2007 10:12 am ((PDT)) Hi all, you can use a small DC motor (battery operated fan for example) as a simple tachometer if you have a multimeter. Set the multimeter to measure DC voltage (not current in amps) and find some way of allowing the motor to be turned by the lathe, perhaps a cone on the motor shaft that you hold in the end of the spindle for a moment to get a reading, or a rubber wheel that you hold (very carefully) against the chuck, or more safely against a drive pulley rim. I used my pillar drill with its 6 speeds to produce a calibration graph for the motor (I got 310 RPM per volt on my motor), which I later checked with an optical tacho -- it was close enough (318 RPM per volt). If it's a cheap analogue multimeter, make a new card for the meter section with the speeds displayed instead of volts etc. If you're after a continuous display then you could fix the DC motor somewhere. If you attach the motor somewhere on the drive train you would of course have to take account of any drive ratios involved. Hope this helps Toby ------- Re: Reading headstock rpm Posted by: "David Forsyth" notLeftBehindx~xxiwr.ru.ac.za Date: Thu Oct 25, 2007 1:43 pm ((PDT)) go to bicycle shop buy cheap bike speedo, with magnetic sensor mount sensor stick magnet to spindle (not chuck, you want the smallest possible diameter shaft that still gives you a good on/off signal, this reduces the transit time and gives a more reliable signal) set wheel circumference in the speedo to some multiple of 1.6666666. 1.6 meters or 16.6 inches or 166.6666 cm or whatever units the unit will take. readout will be in RPM. on my unit it read rpm/10 because the display is limited, but it worked jut fine up to 600rpm on my ML7 David http://iwr.ru.ac.za/~iwdf/ -------- Re: Reading headstock rpm Posted by: "David Morrow" morrow2002x~xxlightspeed.ca Date: Thu Oct 25, 2007 9:07 pm ((PDT)) In a slightly different application, I mounted one on my motorcycle for riding in the U.S. (my speedo was metric -- I'm in Canada). I mounted the magnet on the wheel which was about 17" diameter so I'm not sure if diameter will make it any more or less accurate. I tried to mount one on my Sherline mill to calculate RPM but couldn't get it to work. I found out later that the electrical noise from the motor was the problem so it's intriguing to hear that you got it to work. ------- Re: Reading headstock rpm Posted by: "p_ioannidis" pioannidisx~xxtpg.com.au Date: Thu Oct 25, 2007 9:49 pm ((PDT)) Hi David, if you are referring to my comments re: using a proximity sensor? Yes you can get interference from the motor, the instructions that came with the one I used said to run the sensor wiring as far as possible from the motor and not in the same room as the motor's wires. Treat it as one would Communication cabling and electrical, each in separate conduit, parallel is ok, at least 5 - 10 cm apart, even when they must cross each other. All should be good from there. Peter ------- Reading headstock rpm Posted by: "novice1943nl" j.roos12x~xxchello.nl Date: Mon Oct 29, 2007 4:22 am ((PDT)) Hi group, thanks a lot for all your reactions. Gives me a lot to think about and to investigate. I will let you know in the future what I have done with your suggestions. Novice ------- Re: Cigarette paper trick [taigtools] Posted by: "Clive Foster" clive_fosterx~xxtalk21.com Date: Sat Oct 6, 2007 7:46 am ((PDT)) If you consider something thin and fairly stiff like a 1 thou feeler gauge lightly trapped between a sharp edge and a circular object, its resistance to being pulled out will be least when you are making a straight pull along the line tangent to the side of the circular object takes a sensitive grip but the effect can be felt. I imagine that if you are really good, it's possible to do the same with cigarette paper but I'm darned sure I can't do it. I can, just, manage with a feeler gauge and have once used it in anger (for a lab set-up, not machining). I'm pretty sure that the man who showed me the feeler gauge trick in the first place did so as a curiosity or even as an exercise in confusing callow youth -- not as a serious technique. However he did also show me the ruler trick for verifying that a lathe tool is on centre height and the cigarette paper trick for finding an edge. There seem to be several versions of these tricks. I was told to oil one end of the cigarette paper to stick it to the work-piece and hold the other whilst moving the table. When the cutter tore the paper away, it was supposed to be within half a thou. Fine on a small machine, I was shown on a BCA (I think), but on a bigger one the method was to oil the whole paper and watch for the cutter to flick it off when it would be between 1 and 0.5 thou from the surface. I was told that for the rule trick you want a fairly small diameter chucked up. No more than an inch. The larger the test diameter the less sensitive it becomes. Also if the edge is high, the tool rake (and probably the slides) limit the angle of tilt on the rule. In principle you could devise a calibrated device working in this manner where the angle of tilt or distance offset at the end gives the tool height setting error. Clive ------- Re: Advice on setting up a 4400 [sherline] Posted by: "Ron Ginger" rongingerx~xxroadrunner.com Date: Mon Nov 26, 2007 10:08 am ((PST)) >> I dont know your age but, I am 64 and my eyes dont work well. >> Consider the DRO option. > You don't have THAT many years on me, and I'm not getting any younger > myself. DRO sounds like a good option. I would not buy Sherlines DRO. It is simply a turns counter on the leadscrew, it does NOT measure the position of the tables. Resettable handwheels will do everything the DRO will do, except give you a pretty red display. However, a 'real' DRO can be made from 2 of the electronic calipers, for MUCH less money than the DRO. These will actually measure the location of the table. Another approach an old friend used was to mount his lathe and mill to a sheetmetal table top. Then he could place a magnetic base indicator anywhere around the machine as needed to give accurate measurement of table moves- limited to the indicator travel, but often thats good enough. Generally I like Sherline machines, but their DRO, and their CNC controller are two poor designs. They ought to stick to mechanical stuff an avoid electronics. ron ginger ------- Elephant's Foot for Dial Gauge [MyMyford] Posted by: "tr0up" tr0upx~xxyahoo.com tr0up Date: Sun Dec 2, 2007 10:58 pm ((PST)) This came up just now in a discussion of the difficulty of being sure that what you're measuring when you run a dial gauge along a test bar is not partly the result of the bar drooping or rising. (One could test for this separately by running along the top of the bar, but the same problem simply shifts through 90 degrees.) The simplest solution is a flat pad tip for the indicator, known as an "elephant's foot" I thought it was worth raising this in a separate thread for those who have not come across this. They're not difficult to make, and (apart from alignment checks as above) very handy for - truing up a threaded or knurled workpiece; - truing up a keywayed workpiece (goes much quicker when you can keep rotating in the same direction); - setting up the compound or the taper turning attachment using a sample (male) taper. Lacking something along these lines it is difficult to be sure the tip of the indicator is exactly on centre height -- in the specific case of a taper, any height error will screw things up. If you're not prone to shop envy, (or if you've only got a side-lever type DTI) check out a more elegant solution in the second part of the page at http://www.frets.com/FRETSPages/Machining/Tooling/IndicatorHolder/indica torholder.html Frankly, all the tips at http://www.frets.com/FRETSPages/Machining/ are inspirational. The guy has a real knack of coming up with elegant ways of improving on tools and procedures, and most of them are much simpler than the one instanced above (although, in his defense, his solution is better than an elephant's foot, as the indicating face is automatically vertical). But the quality and fitout of his machines, and the finish level of his projects, would not be seen in a home workshop elsewhere -- in fact, where I come from, it wouldn't be found in 95% of toolrooms ... so be warned! ------- Re: Level question [Min_Int_Comb_Eng] Posted by: "Donald H Locker" dhlockerx~xxcomcast.net Date: Wed Dec 26, 2007 7:20 am ((PST)) mgbrv8 wrote: > If you are setting a machinist level and you don't a level to compair > it too or a level surface, what do you do to set it? Dave Compare it to itself. Set on your surface plate, and shim the plate until it reads level. Reverse the level (end-for-end) and it should show level again. If not, re-shim your surface plate to half the difference, adjust the level to the new presumed level surface and repeat. HTH, Donald ------- Re: Level question Posted by: "Larryg" lnjgalvinx~xxproaxis.com Date: Wed Dec 26, 2007 10:20 am ((PST)) Dave: A level is a self calibrating tool. Donald gave one way to set it. I will give another, similar method. I used to travel with levels so checking and setting them was a constant thing. Find a clean, flat, and nearly level surface. Surface plate is ideal but you can use a table saw, mill table or something similar. Clean the spot you're going to test at, and remove any burrs is necessary to that the level will sit flat without rocking. Feel the bottom of the level and check for burrs there too. Clean and stone the level as necessary. Now place the level on the reference surface and mark the position of the level in both X and Y directions. You should have a reading on the bubble of the level. If the bubble is pegged to one end, then you will have to do some leveling of your reference surface as the bubble must be floating. Let's say it is reading high to the left two marks. Now rotate the level 180 degrees, carefully placing it back on the reference marks, and take a reading. If the bubble is reading high to the left two marks, then your level is good to go. If it reading different, say high to the left 4 marks, then you have some work to do. If you can adjust the level in the position it sets, then adjust it so that it is reading high to the left three marks and you should be good. Rotate it 180 again and confirm that it reads the same. The concern is that it reads the same each rotation. It does not have to read level unless it is on a known level surface. Lg ------- Re: checking headstock alignment with a 'virtual faceplate' [MyMyford] Posted by: "tr0up" tr0upx~xxyahoo.com tr0up Date: Tue Jan 1, 2008 1:00 am ((PST)) Earlier this year, Piet Butter wrote: > Had an attempt yesterday trying to measure alignment against the 7" > face plate but that did not work out as the face plate has quite a > bit of a wobble, which can be easily fixed as soon as I have the > headstock square with the ways. I came across this looking for a different matter, but I wish I'd spotted it at the time. Piet doesn't seem to be within reach of a computer at present, but for the sake of anyone who might grapple with this topic: The best way to simulate a dead flat faceplate, dead square to the spindle axis, is to use the 4 jaw chuck and a straightedge and a DTI. As well as being cheap (or free), it gets away from one of the limitations of the (expensive) test bar when you need to check the bedways vs headstock alignment: being round, the test bar is problematic if the top of the bed dips towards the chuck. In this scenario, the probe of the DTI will travel below centre height on the bar, a spurious deflection of the needle will result, and confusion ensue. The basic idea is to grip the straightedge sideways in the chuck (using a crafty dodge described below), clock the face (the narrow face which faces towards the tailstock) at (say) the far end, near the motor, and repeatedly tap it more square in the jaws so that when the chuck is spun half a turn, the other end converges on the same reading on the DTI. Now you effectively have a datum face, square to the spindle axis, and true to the limits of the resolution of your DTI. 'Fabelhaft', to coin an archaic German expression of satisfaction. Clamp a machinist's square to the bed lying flat, pack up one end of the thin blade to keep it level if it's that sort of square (personally I like the simple, rugged one-piece toolmaker's pattern which are made from flat gauge plate) Now run a DTI (on a surface gauge, with the dowels pushed down) across the square to get one face parallel to your datum in the chuck, then tighten the clamps and run the same gauge along the long blade of the square, indicating against whichever shear is not used to guide the carriage (if this is not obvious, Search recent posts for "wide guide" or "narrow guide"). This will tell you if the headstock needs to be swivelled. The correct answer is "no". (There's almost nothing you could do to a Myford, without rendering it unfit for further service, which would require such drastic measures) The other shears can now be clocked up, and a diagram drawn on graph paper exaggerating the x scale by say a factor of 100 or more, depending how much deviation you've measured, to give you a picture of the shape the shears are in. Now that you know if the bed is true, and if so, where, you can also check the front face of the cross slide, with reference either to the 'virtual faceplate' or the square on the bed. Then if you're really keen, take off the cross slide and check the front dovetail on the carriage. Use a piece of ground silver steel or similar under the overhang of the dovetail, then butt up a ground parallel or what have you to make a flat surface for the indicator probe. A ground parallel will also serve as the straightedge in the chuck - ideally it wants to be thicker than a steel rule, but the rule out of a decent combination square will do at a pinch. Aternatively, use a piece of high quality keysteel (sold at most engineering supply houses), preferably at least 12mm square, and definitely one that has been wrapped in a bunch in an oily wrapper rather than kicking around the shelves getting bent. * * * * Some who are new to lathes, and a few who are not, may not have realised that a 4 jaw chuck, because the jaws are ground at 45 degrees so they can almost meet in the middle, can be used to grip any rectangular or square section workpiece whose length is the maximum which can swing in the gap - 250mm, in the case of the 7 series. The trick is to open the jaws quite wide, turn the chuck so the 4 jaws, viewed from the tailstock, look like a X rather than a + , and place the bar horizontally so it lies on (say) jaws 3 & 4, on those 45 degree faces. Then use the chuck like a vice, where jaws 3 & 4 are moved together as though they were a single vice jaw, and ditto with 1 & 2, to centre the workpiece (for this exercise, by eye using the engraved rings against a feature of the jaws is plenty). Leave the final tightening until you've squared the bar across the bed as described above. If you're doing this with a view to machining the bar, you may have to include packers between the jaws and the workpiece, if it is of low sectional height, so that the jaws will be further apart. If you have a 4 jaw SC chuck (wonderful things) this is a really quick dodge. What's more, such a chuck, clamped lying on its back on the table of a drill press or (drill) mill in X rather than + configuration, will self-centre work, and hold it either across or along the bed in the case of the mill, without moving anything. ------- Re: checking headstock alignment with a 'virtual faceplate' Posted by: "Eric Parsonage" ericx~xxeparsonage.com Date: Tue Jan 1, 2008 3:08 am ((PST)) Troup, Thanks so much for this. I was wondering how I would be able to check if the cross slide was setup up correctly; now with this straight edge in the 4 jaw that becomes trivial. Regards Eric ------- Re: Dial indicator [taitools] Posted by: "Ken Cline" clinex~xxfrii.com Date: Fri May 9, 2008 2:58 pm ((PDT)) On 9 May 2008, at 12:30 PM, stl.bill wrote: > I have seen dial indicators from a wide ranges of sources. They vary > in cost from $15 to hundreds. I will be using it initially for > centering stock in a 4-jaw chuck. What would be some of the > capablities I might look for such as travel, accuracy, etc. It depends. How much accuracy do you need? You can likely get by with a $15 dial indicator that reads in thousandths (0.001"). I have found that wiggling the probe of cheap indicators changes the reading by about a thousandth, so you'll get accuracy somewhere between .001-.002". I assume that you will get a much smoother and durable instrument if you spend the $100-$300. I prefer a dial test indicator (the kind with a test arm than swings rather than a plunger) for centering parts in my chuck (aligning clamped parts and vises, truing my mill, etc.). A cheap DTI costs about $37. I was advised to get one that reads in "tenths" (0.0001") and do not regret spending $157 for a mid-priced Mitutoyo. The Mitutoyo reads steady as a rock, but has plastic parts that could limit its durability under heavy use. In any case, the higher resolution instills confidence when getting down to that last .001. Travel is limited (0.016" for my DTI), but it is not a big deal for me. I use an adjustable arm to hold the indicator (it has an elbow that bends as a screw is turned). Attempting to clamp the DTI without some sort of fine adjustment could prove frustrating. It may be worth noting that bits of dust or dirt in my shop are often .0001" or larger. Using a .0001" indicator requires strict attention to cleanliness if you want accurate results. I would not be surprised to hear from others who think it is overkilll for centering stock, but, hey, I learned about measurement in physics lab rather than machine shop ;-) ------- Re: Dial indicator Posted by: "Nicholas Carter and Felice Luftschein" felicex~xxcasco.net Date: Fri May 9, 2008 3:04 pm ((PDT)) In addition to what Ken said, the advantage of a test indicator is that you can true up work not only by the OD, but by the ID, which is handy when the only machined feature is a bored hole. Of course over time you find uses for a bunch of different indicators and attachments. See our homepage at www.cartertools.com/nfhome.html ------- Re: Dial indicator Posted by: "kd006" kd006x~xxyahoo.com Date: Fri May 9, 2008 3:26 pm ((PDT)) Ken, I am just curious, since your indicator only has a travel of .016 how do you rotate the chuck to center? I would think one would need to keep the indicator in place and hold the plunger back so you could rotate to the other face on square or ocatagon stock? Guess I have to go back to Nick's page and read the "how to center document" again, haven't had the need yet but I am sure it will come up sooner or later. I have the El-Chepo set from LMS and the worst part of it is the mounting arms and adjustment, going to have to make some rod clamps with setscrews, those big plastic wing nuts get in the way and it seems a third axis is also needed as it's a contortion job to get the dial where I want it without hitting one of them. As for measuring an ID, my kit came with several tips including one or two with a right angle tip that would seem to do for inside measurments as long as the hole was large enough. Kristin ------- Re: Dial indicator Posted by: "Ken Cline" clinex~xxfrii.com Date: Fri May 9, 2008 8:45 pm ((PDT)) My lathe is pretty new and I have not needed to accurately true polygonal stock. I use the chuck on a rotary table on my mill, in which case I sometimes attach the test indicator to the headstock and accurately move it out of the way when precisely locating a non-round work piece. Mounting the test indicator to the crosslide should do the same trick on a lathe. Note that the end of the test arm has a ball which allows it to move back up into position even when moving parallel to the spindle's axis. Does that make sense? I also use a laser pointer to align rough stock, where a few thousandths of an inch one way or the other makes no difference. Reasonably cheap, fast, and no problem dealing with corners breaking the beam, though the accuracy is subjective because the beam's shape is imperfect. ------- True centreing using a Fixed Steady [MyMyford] Posted by: "tr0up" a.troupx~xxemail.com Date: Tue May 20, 2008 6:28 pm ((PDT)) The underlying principle of the method relies on the fact that a steady constrains a cylindrical workpiece to rotate about the long axis of the cylinder. This holds true even when neither the steady nor the tailstock line up with the headstock's axis of rotation. So in spite of small deviations from truth in the machinery, a centre hole drilled in a length of precision ground bar with the outboard end held in the 3 point steady (as close as you can get to the end), will be perfectly true to the bar. To get the fixed steady near enough, I get the work running true at the chuck, then slide the steady as close to the chuck as the gap allows, push it back against the (inside rear) reference shear, clamp it temporarily and bring the jaws up to just touch the work. Now it can be slid back to where it belongs. Don't forget a dab of anti- scuffing paste or similar on the tip of each bronze jaw before offering them up. Replenish it often. Other steady tips: to steady a soft workpiece, such as brass or alu alloy, wrap a strip of card around the work, inside the jaws. Bring the ends out and clamp them between the faces of the steady at the clamping slot. (Provenance: Ian Bradley, the Amateur's Workshop, p22 - a great book, to my mind, and for some reason an author much maligned on the Internet) When there is a risk of chips getting into the nip of the jaws and ruining the finish, shroud the steady with a rag. It should be carefully secured in such a way it cannot get wound into the job. Bikini-brief underpants are the ideal shape. If you're gripping on a hardened surface, doing crucial work, you can aim for a small amount of preload by setting the jaws up with the clamp screw loose, then nipping it up judiciously. ------- Realigning the tailstock centre [MyMyford] Posted by: "tr0up" a.troupx~xxemail.com Date: Tue May 20, 2008 7:39 pm ((PDT)) Method 1 For lathes whose bed is relatively unworn and well aligned with respect to the headstock: Set up a DTI from the chuck or faceplate (either using a mag base or a rod) so it rotates when the spindle is turned by hand. Clock up the tailstock's taper bore [or the OD of the quill/barrel if you don't have a side-lever DTI, or if the bore is too scored. The keyway is a pain in this case; draw a pencil line on the opposite side of the barrel level with the top of the keyway and stop here when sweeping) Adjust the clock face until the deviation is equal either side of zero when you sweep between front and back. Wind the adjustment across until it reads zero. Check by sweeping again. Method 2 For lathes which are quite worn, where you nevertheless need to turn a reasonably long shaft substantially parallel: Following the procedure in the post "True centreing using a Fixed Steady" at both ends of a length of precision ground bar will furnish you with a precision test bar for lining up the tailstock centre with the headstock center. (NB: Getting tailstock roughly lined up first will pay off as otherwise the tip of a small centre drill may be snapped off. A quick method is to pinch a piece of thin sheetmetal between head and tail centre, and adjust so that it lies perpendicular across the bed) The test bar should be about the same length as the crucial workpiece you want to turn parallel. Check for play in the mandrel bearings (and reduce shims if necessary), check for burrs in the taper bores and scrape the raised ridges if necessary with a triangular scraper, clean the taper shanks and bores, take a skim off the soft centre in the headstock with compound set round to 30 degrees, and set up the test bar between centres. Take the time also to adjust the carriage gib (which bears against the front shear or vertical guide face of the bed) per the procedure in the manual. Run the clock along the top centreline first to check that the tail centre is within say 0.2mm of the same height as the head. If not you'll need to machine or shim the underbody of the tailstock. If you drill tiny holes, it needs to be much closer that that. Now set the clock up on the side of the bar at centre height and note the reading every 50 or 100mm (latter for a long bar). Always come up to the position from the same side, to minimise errors due to residual gib clearance (and possibly a convex-worn guide face), where they bear on the shears. Plot the readings as a graph, with the deviations exaggerated by 100 or 1000 times. This doesn't have to be particularly carefully done; the graph paper can be homespun, ruled up in five minutes. Draw the "best fit" line, and measure how much deviation it implies at the tailstock end relative to the headstock end. That's how much you want to crank the tailstock across (in the correct direction!) By measuring the differences between the best fit line and the actual plot, this test will also tell you how much minimum variation in radius you can expect when turning work of that length (in practice it will always be more, due to deflection, tool wear, etc) ------- [atlas_craftsman] Re: Appropriate Indicator of centering work in a 4-jaw chuck Posted by: "Steve" skadsmx~xxgmail.com Date: Thu Jul 17, 2008 5:26 am ((PDT)) > Another way if your work is odd shaped (that is where a four jaw shines) you can put a punch mark where you want the center to be located. Then a simple piece of drill rod about 8 inches long with a point on one end and a depression made with a center drill on the other and pinch that between the work and the tail stock center and that gives you something to indicate with your indicator. < You can see how I did just that here: http://www.chaski.org/homemachinist/viewtopic.php?t=76553 Steve ------- new article: a low cost X axis DRO for a lathe [Metal_Shapers] Posted by: "Rick" rgsparberx~xxaol.com Date: Thu Jan 1, 2009 6:20 pm ((PST)) This may be old hat for most of you, but if you don't know the trick of using a digital caliper as an X axis DRO for a lathe, you may find the following interesting: http://rick.sparber.org/XaxisDRO.pdf Rick Sparber ------- NOTE TO FILE: The next question had been how to center square stock in a 4 jaw chuck. Lots of answers fooling around with a DTI that had to be retracted to miss the corners if you tried indicating on the flats of the square stock. Then came David Clark's simple and elegant solution. Alan Haisley had an alternate easy solution. Thanks, everyone. ------- Re: 4 Jaw chuck [sherline] Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Mon Jan 19, 2009 5:00 pm ((PST)) In sherlinex~xxyahoogroups.com, "DW Holtman" wrote: > Hello, I have pretty much figured out how to align round stock in a 4 jaw chuck and get it centered. What is the best way to align square stock, to get it centered? Use the corners or the flat sides? < Indicate the backs of the jaws. DC ------- Re: 4 Jaw chuck Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Mon Jan 19, 2009 6:19 pm ((PST)) Use a really fat thickness gauge. Then remove it for the rotation and add back for the next measurement. Alan ------- DRO for Atlas Mill (made from discarded inkjet printers) [atlas_craftsman] Posted by: "mckgyver64" junkmalex~xxemailaccount.com mckgyver64 Date: Wed Jan 28, 2009 8:07 am ((PST)) Just finished a DRO (Digital readout) project for my atlas mill, figured you guys might be interested. I tried to minimize the aesthetic impact by concealing all encoders and scales within the castings. Still a work in progress, but functional at this point. Here is the link to my work http://mckgyver.pbwiki.com/DRO McKGyver ------- Re: DRO for Atlas Mill (made from discarded inkjet printers) Posted by: "Harry" hcapperx~xxverizon.net Date: Thu Jan 29, 2009 2:05 pm ((PST)) Wondering what the advantage, other than getting everything from the pig, including the squeal, is to making a DRO from discarded ink jet parts? For about 50 bucks, you can purchase a DRO which has reversable readout, .0005" resolution and pretty much turn-key, once you figure out a way to mount it. One of the many examples on eBay ------- Dial test indicators for lathe work - need advice [taigtools] Posted by: "louis.devos" louis.devosx~xxyahoo.com Date: Sat Mar 7, 2009 6:58 am ((PST)) I am looking at getting a dial test indicator for some work I am doing on my taig. I am making small metal tubes out of solid brass stock, and need the inside and outside diameter to be exact along the length of the tube. The tube length will usually be 1.5" or shorter. The ID of the tube will vary, could be be as small as .150, and the OD could be as small as .180. I know I can use a regular indicator to test the OD fur run-out, but will a dial test indicator work for the ID work, were micrometer jaws can't reach? Thanks. ------- Re: Dial test indicators for lathe work - need advice Posted by: "warren hughes" ofujunkcyx~xxyahoo.com Date: Sat Mar 7, 2009 7:24 am ((PST)) Try Enco page 328 for a Dial Bore Gage. This should fix you up; check the specs -- $55 bucks; there are even more pricey options. And also an inside dial indicator. Warren Hughes ------- Re: Dial test indicators for lathe work - need advice Posted by: "leon Heller" leon355x~xxbtinternet.com Date: Sat Mar 7, 2009 7:46 am ((PST)) You could turn down some rod and make your own plug gauges. Leon ------- Re: Dial test indicators for lathe work - need advice Posted by: "mike maxim" mammikex~xxyahoo.com Date: Sat Mar 7, 2009 8:02 am ((PST)) Look at this micrometer at useenco.com item number 326-1126. I think this is what you are looking for. You could also use a gauge block with your test indicator to check the thickness of your tubes. ------- Re: Dial test indicators for lathe work - need advice Posted by: "Clive Foster" clive_fosterx~xxtalk21.com Date: Sun Mar 8, 2009 6:21 am ((PDT)) Once you get below 0.250" a dial type bore gauge simply won't enter. In the small sizes you are stuck with either go/no-go gauges or the expanding ball thingy sets. The expander thingies work well, also have the huge advantage over dial types of being light and easy to handle. The dial on a stick beasts are quite cumbersome to handle and there is a fair bit of art involved to get accurate, repeatable measurements. As ever, at least at the prices we can pay, a dial is a comparator not a calibrated full range instrument so you have to arrange to get the basic size calibrated so the dial can read small variations. Personally I don't trust them over more than about 25 % of a single rotation of the scale for accurate work. Ages back I put an expensive one against one of Heidenhains best probes whose calibration I'd verified optically and found the variation "interesting". Worst case movement measurement errors of over 5 thou on a tenths thou calibrated gauge were no great surprise to me but amply shut-up the project manager who didn't want to spring for a Heidenhian. My small hole probes are calibrated types by M&W so they can be read directly rather than needing a separate micrometer. However if it's got to be really right, I still check against slips. How are you getting the holes to size? A D-bit is said to give best and most accurate results for this sort of thing. If I had a bunch to do I'd reckon it a good excuse to try ball sizing to get a nice smooth bore to just so dimensions. Clive ------- Measuring hole diameters [taigtools] Posted by: "John" johnsaundersx~xxpetruspartners.com Date: Mon May 25, 2009 8:45 pm ((PDT)) This is a beginners question (or at least evidence of being self-taught). I need a way to measure hole diameters more accurately than my digital calipers can. The tool will be mostly be used to measure diameter but also, if possible, to get a feel for concentricity (i.e. for when I'm milling large, circular pockets). I also would like to use the tool to measure drilled holes. For example, if I use an inexpensive 0.5" drill bit in my drill press, I'd like to be able to measure what the diameter of that hole is (and concenticity..) as compared with a more expensive drill bit. Ideally, I'd like to do this for holes as small as 1/2" and as large as 2" - but recognize that may not be possible with the same tool. Because I have such a wide range of diameters, I can't justify the hundreds of dollars for all of the sets of pin gages. I don't need measurements any more accurate than 1 thou. Is there a good hand-type tool for this? Also - while at a "real" machine shop once, I saw a benchtop device which had a large measurement dial on the face. I don't remember it well, but think that it had 2 or 4 "fingers" (just like a dial test indicator) which you rotated the part around and the measurement dial showed the concentricity. Anyone know what this tool/device is called? ------- Re: Measuring hole diameters Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Mon May 25, 2009 9:08 pm ((PDT)) You have a couple options. First, with practice, you can learn to measure with a digital caliper to 1 thou or close to it. Ideally, you can practice on a ring-type master, but DOM tube will get you pretty close. Aim for consistency, and check that the ID jaws on your caliper are sharp. The next tool you can try is a telescoping bore gauge. This also take practice, and, since it is a two part measurement, also can be prone to error. It is all about the feel of the gauge in the hole and the gauge in the micrometer. Basically the way they work is they are spring loaded, so you can slide them into the hole, then tighten them to lock in the measurement. You have to rock them side to side to get an accurate measurement. Once you have the gauge, you can take an OD micrometer and measure the gauge. These gauges come in sets from 0.3"-6". Also related to telescoping gauges are small hole gauges, which measure from 0.125-0.5". They also make dial-type internal calipers, which can measure variation over the depth of a hole, but tend to be challenging to use. Also available are internal micrometer calipers, which come in 0.2-1.2 and 1-2 varieties, but are limited to about 3/8" deep. You won't be able to measure taper or out of roundness over long distances. Finally, there are the dial bore gauges and Intrimikes, which are what you saw. You're looking at $200+ for as little as a 0.5" measurement range -- far out of the price range of most hobby machinists. You also need a full set of setting rings, which are like calibration masters for normal external micrometers. Michael ------- Re: Measuring hole diameters Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Tue May 26, 2009 9:39 am ((PDT)) I use the same principle as a tapered gauge: http://www.leevalley.com/wood/page.aspx?c=1&p=32520&cat=1,43513 Turn a shallow taper on a metal bar, drop it in the hole, and apply calipers to the bar directly above the part being measured. Your measure- ment will be very slightly bigger than the hole size. The shallower your taper, the less difference you will have. I think that you could figure out the exact amount to subtract from the measurement by measuring an accurate reference hole and then finding out how much bigger your measure- ment was. If you are using drill-bits to make the holes though, this is really overkill. The other interesting thing you see this way is how far out of round the hole is. On a through-hole, stick the tapered plug in the top, and shine your pocket flashlight into the other end. Observe where the light leaks out. A badly ground bit will make a three-lobed, oversized hole that is quite distinctive. ------- digital calipers [atlas_craftsman] Posted by: "gene_isley_7" gene_isley_7x~xxyahoo.com Date: Sat Aug 1, 2009 2:06 pm ((PDT)) Hi from a new member who has been enjoying the information in the group discussions. I bought a 6" craftsman atlas 101.0703 lathe a few weeks ago. I am Trying to get set up to have some fun and learning experiences this winter. My question for now is how usabe is a good digital caliper for a starter. Expect many questions in the future. Thank you all very much Gene Isley ------- Re: digital calipers Posted by: "jo barden" jobarden422x~xxmsn.com Date: Sat Aug 1, 2009 2:26 pm ((PDT)) Hi Gene: in all honesty digital calipers are useful but be they digital or not you have to get used to using calipers in the same way as using a micrometer, the "feel" and "drag" of just right or over tight has to be experienced along with correct pozitioning so that you are measuring correctly and not at a slight diagonal. I used to teach general engineering and as a bit I used to place a 1/2 thou feeler guage on the bench and get the students to run their fingers over it with their eyes closed, even my rough fingers can feel it, try it. I would get a cheap pair of calipers and Mic, gain experience, if possible talk to others and ask as you are doing now, My long suffering wife will attest to the fact that we always want more "bloody bits of metal" gain experience and if you drop something on a cheap pair you have not lost a great deal. I have bought a cheap pair and "butchered" them to make a measure for cross slide measuring, I just have to remember to double it. hope this helps Jon ------- Re: digital calipers Posted by: "Richard Schaal" rschaal_95135x~xxyahoo.com Date: Sat Aug 1, 2009 2:29 pm ((PDT)) When I started acquiring stuff to go with my other acquisition, I definitely wanted digital calipers. However, after chewing through one set of batteries after another, I have now set them aside and use a dial caliper instead. It reads out to the same level of precision, and doesn't demand to be fed pricey batteries on a regular basis. My $0.02 Richard ------- Re: digital calipers Posted by: "Michael Schetterer" finegrainmetalx~xxhotmail.com Date: Sat Aug 1, 2009 2:39 pm ((PDT)) The two most-used measuring tools in my shop are a 6" rule and a 4" dial caliper. I use them on almost every single part I make. I know the caliper is only good to a couple thou. If I need to be within a thousandth or better, then I use a (non-digital) mic, but the mic only comes out at the end. I've never been partial to digital measuring tools. I like seeing the movement of the hand on the dial, since I get some feedback that you don't get with a digital. Mike ------- Re: digital calipers Posted by: "Starlight Tool Services Ltd" starlight_toolsx~xxtelus.net Date: Sat Aug 1, 2009 3:38 pm ((PDT)) Gene: I have a Mititoyo Vernier Caliper, a Smiec Dial Caliper and a Samona Digital Caliper. There are also a couple of 4" verniers and a 6" plastic vernier in the drrawer that seldom if ever get used. I have had the digital for about 10 years and it gets used the most often. It is accurate enough and so far I have never had to change the batteries. One of the great features is that you can do metric to Imperial conversion just by pressing a button. If I need better accuracy then I get out the vernier or the mics. Yes a decent digital caliper is definitely worth having for most shops. Walter ------- Re: digital calipers Posted by: "TCHarex~xxaol.com" Date: Sat Aug 1, 2009 6:04 pm ((PDT)) Hi Gene: I suggest you get the cheap 4" digital calipers from Harbor Freight. They are on sale occasionally for $14.99. The four inch will get in to measure on set ups on a six inch lathe better than the bigger ones. I know, I have used both on set-ups on a six inch. I suggest, don't get the Mititoyo or other name brand. They all work the same way and have the same external readout plug, so I suggest they probably use the same chipset. Go with the cheap one because you won't shed as many tears when you eventually drop something on it and break the glass on the digital readout. Yes, they are glass to stand up to solvents and oils used in the shop. If you have access to a mill, then a good project is to design a set of clamps to clamp the caliper on the lathe that will measure the carriage travel. A poor man's travel dial. As for battery use, mine don't use them up unless I leave them turned on, maybe I am lucky. I have gotten a year out of a battery on one set used on the weekends. Regards Tom ------- Re: digital calipers Posted by: "catboat15x~xxaol.com" Date: Sun Aug 2, 2009 9:14 am ((PDT)) Digital calipers, micrometers, any measuring tool you can name. First you have to learn to measure things. A mike is NOT just a precision welding clamp. You have to learn to bring the faces onto your work to be in contact, but not hard enough to distort the frame or deflect what you are trying to measure. Digital devices are easy to read, but that only saves you the "work" of learning to read a mike or a vernier. For a good exercise get a set of thickness gauges and try measuring those with your mike and with your digital read outs and see how putting pressure onto the measuring device will change the readings. Then too, measuring for what purpose? Are you trying to make something according to a drawing? Or are you making part "B" to fit part "A". It is a different situation if you are making something that must fit into some bracket on every Ford made in the last ten years, or making something that must fit well into or onto your one-off project? As an example I like to make model steam engines. Sometimes I have to fit a commercial ball bearing into the frame of the engine. There I have to bore or drill and ream a hole that will accept the existing bearing race without wobble. (The shaft that runs in that bearing too must fit the existing commercial bearing.) So I have to turn things to fit an existing constraint. But, if I have made a cylinder and piston set for the same engine, I only have to make the piston fit the cylinder that I have also made, so I don't really care if the cylinder is a few thous (or hundreds maybe) off the plan dimensions as I will make the piston to match that particular bore, so have two places to make adjustments. As you learn to play in this hobby you will find out some surprising facts. Things like a drill never makes a straight round hole in your work. A reamer will make it better, but best is boring. Your fingers can measure a thousandth pretty easy; take two short rods, one a thousandth's longer than the other and hold them between your fingers. You can feel the difference with no effort. Comparing diameters takes a bit of practice, but feel a 1/8 inch drill along with a number 30 and see if you can tell which one is smaller with your fingers. Purchase one of those cheap drill sets from Harbor Fright (Mis-spelling intended) then as they break or dull replace those you will be using the most often with better quality drill bits purchased one at a time. When drilling a hole that must be tapped, go up a size or two from most tables; saves a lot of taps over the years and a 60% thread is almost as strong as a 100% thread. (I have a set of tables from Brown and Sharp in a little booklet that shows drill sizes for tapping with 100%, 80, 60 and 50 percent sizing. I will generally use the 60% size for work where I will have more than two or three thread engagement. Oh, and don't forget that work on your lathe is hot when you have been cutting. Heat expands metals so the cold size will be smaller than you measured when you were making that piece. Keep away from hot sharp swarf. Leave watches, rings etc in your pocket and long sleeves are just waiting to wind up in your work and pull your hand or arm into dangerous places. Keep your work area clean and neat (and if you ever see my shop, I will deny everything I said) so you don't stumble into some place you should never go. A great hobby, have fun and learn a lot. John Meacham Littlerock, California 12 inch Atlas lathe, Mini-mill, band saw and a rusty file ------- Re: digital calipers Posted by: "danaz.chandler" djnx~xxieee.org Date: Sun Aug 2, 2009 12:27 pm ((PDT)) My preference is for a good dial caliper. I like to see how the needle moves as I 'feel' the part. I take comfort from seeing the needle dip to a minimum when measureing a thickness. In one sense, the needle can show you much more than .001 when doing this. Also, digital vs analog uses different parts of the brain...Watching a needle zone in on a reading vs watching a digital number rack down is a different experience. One thing is the update time on the digital reading. If you have a digital readout on a mill or similar, I am sure you are familiar with moving the bed faster than the readout update time. With a caliper, this is not an overall issue, but does make you watch it and compute more stuff than just watching a dial move back and forth... My .00001 cents worth.. Dan in Chandler, AZ ------- Re: digital calipers Posted by: "Russ Kepler" russx~xxkepler-eng.com Date: Sun Aug 2, 2009 12:31 pm ((PDT)) On Sunday 02 August 2009 13:18:17 Michael Fagan wrote: > I'd get a pair of 6" Mitutoyo calipers and be done with it. Check it > against something with a known diameter, such as the shank of a drill > bit, not to check the caliper but to calibrate your feel and how much > pressure you put on it. I use my calipers daily and I change the > battery about once a year. Remember that the shank of a drill is frequently smaller than the nominal size due to back taper. A cheap set of gage blocks will still be 10x closer to the right size than a caliper can measure, and you can check micrometers at different rotation angles and lengths. ------- Re: digital calipers Posted by: "Leon Robinson" leon-robinsonx~xxsbcglobal.net Date: Sun Aug 2, 2009 1:30 pm ((PDT)) If you get a dial caliper, make sure that it is 0.100 per revolution, some of the cheaper one are 0.200 per revolution. That said, all of the comments by others are correct. I have used both dial and digital, My preference is the Dial. But you must keep it clean. Leon K5JLR ------- Re: digital calipers Posted by: "jerdalx~xxsbcglobal.net" Date: Sun Aug 2, 2009 6:01 pm ((PDT)) "Russ Kepler" wrote: > On the calipers themselves I prefer the Mitutoyo models with the > thumbwheels, The thumbwheel on a caliper is the single biggest source of errors in the entire unit........Ram that right down on the work and measure.... NOT Best to not have a thumbwheel, and close it on the work with fingers on the outside of the jaws in-line with the workpiece. JT ------- Re: digital calipers Posted by: "Russ Kepler" russx~xxkepler-eng.com Date: Sun Aug 2, 2009 8:04 pm ((PDT)) Well, it does take a little more feel than a lot of users have. Perhaps that's the source of the trouble you seem to have had with it. Use whatever works best for you. ------- Re: digital calipers Posted by: "jerdalx~xxsbcglobal.net" Date: Sun Aug 2, 2009 8:29 pm ((PDT)) > Well, it does take a little more feel than a lot of users have. Perhaps > that's the source of the trouble you seem to have had with it. Not me.... as you may have noticed, I know the right way to use them..... ;-) However, I have indeed seen others have that trouble. And often they blame "crappy calipers" for the inability to get the same reading in successive measurements. And, since the average caliper has been knocking around for a while and the gibs (maybe you didn't know calipers had gibs?) are often loose. In that case, the use of the thumbwheel always gives a bad result. There is no amount of "feel" that will fix that, either. The "squeezing" method doesn't always cancel the effect of loose gibs (although it can), but it does tend to give a much closer to correct result in every case, loose or not. There is a certain amount of "spring" to the gibs etc. The 'squeezing" method avoids excercising that "spring". JT ------- Re: digital calipers Posted by: "Russ Kepler" russx~xxkepler-eng.com Date: Mon Aug 3, 2009 6:38 am ((PDT)) > There is a certain amount of "spring" to the gibs etc. The 'squeezing" > method avoids excercising that "spring". I would suggest that that's exactly what it's doing - springing the jaws against the gib. When you're measuring parallel surfaces it doesn't really matter, but if you hit something nonparallel squeezing the jaws to get surface contact on both is going to force a misread. The sensitivity of a single thumb on a slider or wheel is going to be much greater then multiple fingers on the outside of the jaws, where the same contact force is going to be spread over those multiple fingers. If you can show me a caliper designed to be used in the way you suggest I'll be glad to accept it. 've seen plenty of calipers with thumb rollers, others with sliders - but none with gripping surfaces for fingers on the jaws. I'm not saying that what you're doing isn't right in some cases, I've done it, but it's not a generally accepted method of using calipers. ------- Re: digital calipers Posted by: "jerdalx~xxsbcglobal.net" Date: Mon Aug 3, 2009 6:42 pm ((PDT)) Suit yourself, and keep getting inaccurate measurements. That's probably the reason people say calipers are no good closer than 0.005" . If you use them correctly, which is the way shopbooks and experienced machinists suggest, you'll get better measurements. I suspect you would, if you looked, find substantial reference to that method. But please feel free to use any method you like. BTW, what's this about multple fingers? Where did I say to "clench your fist on it"? OF COURSE you use your thumb and first finger (actually, thumb and middle finger sometimes works a bit better) and you close gently. You do not grab it like Bubba with a grip of iron........ that won't work at all. You put your finger and thumb at the point on the jaws where the measurement will be taken, so there is zero leverage, or as close as possible to it. And if the surface is not parallel, and has no largest point which you wish to measure (as a shaft does), neither method is going to do well, since you have no consistent point to measure. So any issues with that are surely moot. BTW, the little roller has a substantial mechanical advantage, and to make it work requires jamming it down with some force, dulling your sensitivity of touch. Then also, the point of application of the closing force with the little wheel is some distance away from the point measured, so there is a lever arm action tending to "open" the jaws..... The whole point of squeezing the jaws is to apply the force at the point of measurement, letting the jaw 'trail along" with minimal force on it..... instead of applying an umbalanced force that springs it open. All I can tell you is that when I measure something that way, I get consistent measurements that agree with micrometers and gage blocks. I can do pretty well with the little roller, too, and usually do that for general measurements. Of course the mic is better... if you have one where you are... some places where you need to measure accurately may have only a caliper available, and it's good to know how to get the best from it. JT ------- Re: digital calipers Posted by: "TCHarex~xxaol.com" Date: Mon Aug 3, 2009 10:00 pm ((PDT)) I totally agree with Jerdal. Closing the jaws with thumb and a finger adjacent to the diameter or width of the part being measured does not put any spring loads on the jaws. In addition, this gets back to my original suggestion that as the requestor is using a six inch lathe, he should get a four inch digital caliper, not a six inch. It is much less likely to crash into tooling and set ups. When he needs the bigger one, then he can buy a six inch. When he breaks the four inch, it is cheaper to replace than a six inch. When you have to turn it upside down and use it with your left hand, you can't reach the thumb wheel anyway, so I think you should get used to doing without it. The Mititoyo is fine for measuring a dimension on a dozen parts sitting on the bench to see if they pass inspection. Home machinists don't do much of that. Also, just 'cause you spent a lot of money on a Japanese tool years ago, does that mean the rest of us must? I go for the $14.99 unit from Harbor Freight. It is fine for a beginner. Tom ------- Re: digital calipers Posted by: "catboat15x~xxaol.com" Date: Tue Aug 4, 2009 8:39 am ((PDT)) One other point on measuring. Don't expect two calipers or two micrometers to agree. (They may and they may not.) So don't use one instrument to measure the hole, then a different one to measure the shaft. It is too long a discussion for a posting, but also look up the difference between "Precision" and "Accuracy". There was a series of articles in the English magazine "Model Engineer" that showed how a triangular shaped shaft will not fit in a round hole, although the shaft will "mike" the correct diameter at every point. There is a whole field of science and engineering involved in just measuring things and some of the studies made show just how we can be fooled. I.E. shaft in hole, we measure a diameter with the mike or caliper, but we are assuming the shaft is round, maybe it is and maybe it isn't. Then wonder why the shaft will not enter the hole. The old timers did not have the measuring instruments we now have and fits were "loose", "running", "tight" and "force". Then there were "shrink" fits also; had to heat the part with the hole and cool the shaft to get it together. That kind of assembly you want to do in one quick motion, if you hesitate you are stuck forever. When a young fellow wanted to be a machinist in the old days they did not start off on the lathe,shaper or mill. They started with cold chisels and files. I have a friend who lists his occupation as "machinist". What he did when he was working was to take a part and place it in a jig on a CNC milling machine, then press a button to start the program running. He is not a machinist, but a machine operator. He is somewhat amazed at what is done on my Atlas with no jigs or computer. Where are we going to get the people that can repair or make a new part 23-526 from a drawing when one of those fancy CAD, CAM system breaks down? ------- Re: digital calipers Posted by: "doc" n8as1x~xxaol.com Date: Tue Aug 4, 2009 2:57 pm ((PDT)) AMEN.& this was done w/ spring calipers ( u really can "feel" less than a thou w/ them, w/ practice...just for fun, try transferring measurements from inside to outside w/ spring calipers & mic your results )....& it still may be best practice to leave the shaft a little long & take test cuts/ filing til degree of interference is established. then turn rest of shaft...& if the xtra length is not a problem, u r done.. since precise hole diameter is more difficult, at least for me, I always try to fit the shaft/bushing to the already bored/reamed hole.. & depending on amt of material left to ream, alignment of tailstock, reaming fluid, speed, & the astrological sign prevailing, it is EASY to ream a .501 hole while needing .500..( boring straightens out a hole, reaming makes it larger..) as a start, mic the reamer flutes.. not unusual to have one pair larger than spec.. & if IN spec, THEY STILL may not be concentric & will over ream... i have frequently made use of adjustable hand reamers.. machinist friend still reams rifle chambers w/ chuck in tailstock & tailstock not clamped to bed. swears by simply shoving tailstock, & letting reamer align itself. (poor boy's floating reamer holder).. my experience w/ a floating reamer holder is O.K. w/ a piloted reamer. bellmouth w/ out the pilot the one time I tried it... may just be me.. i usually open the jaws of drill chuck abt .020 over reamer shank diameter, & the chuck pushes against the reamer wrench as I crank it.. hope this has some value for those just getting started.. Best wishes Docn8as ------- Working from plans ? [taigtools] Posted by: "tonphil1960" tonphil1960x~xxaol.com Date: Mon Sep 7, 2009 7:10 am ((PDT)) What is the key thing I should know about working from plans? I have worked from drawings before, but not in machining and not to tolerances to be sure. I am going to print out a few plans and study them, see if I can wrap my mind around them better. Thanks Tony -------- Re: Working from plans ? Posted by: "Stan Stocker" skstockerx~xxcomcast.net Date: Mon Sep 7, 2009 9:01 am ((PDT)) Hi Tony, Big question! I'd suggest that the first order of business is to digest the plans enough to have a sense of which dimensions are critical, and which don't really matter too much. An example would be in a mill type engine, the holes in the base and at the ends of the cross slide guides must match up to a good degree or it won't go together at all. The flywheel for a mill engine on the other hand needs a nicely finished perimeter, but final O.D. could vary pretty far from the plan dimension without ill effect. Naturally you can't remove the entire rim or you have too little mass for a flywheel, or leave so much that it rubs on something, but we're likely talking tens of thousandths in allowable size variation, rather than within several thou. As a general rule, if not stated otherwise on the plans, untoleranced dimensions given to three places will be plus or minus five thou. Some may be given as minus 0, plus 0.003. For some reason, it must not be smaller than the target, but can be larger. Considering these factors often gives some insight into the design that might not be apparent. Things like spacers can be tricky, as they may work just fine if both are 1.005 or 0.995, but if something slides under a bar supported by the spacers, then having one at 1.005 and one at 0.995 will have things loose at one end, and binding at the other. Most folks have more trouble boring and honing to a precise size, so it makes sense to do cylinders first, and make pistons to fit. For tooling you could say do sleeves and journals first, shafts and fittings second. Sometimes, the biggest issue is figuring out the order to do things, and how to hold the part while machining it. Sometimes the plans may have a nice little note like "Part of this stub after turning and boring to final size", other times it's all up to you to plan it out. Sometimes completing part of the project gives you the ability to hold work using the project parts themselves as fixtures. In hobby applications, you can usually or at least sometimes get away with "make to fit", although I'd never recommend not learning to work to size or to hold to a good dimension. Cheers, Stan ------- Re: Working from plans ? Posted by: "deanofid" deanofidx~xxyahoo.com Date: Mon Sep 7, 2009 11:42 am ((PDT)) Stan has some good advise for you, Tony. Especially the part about work holding and the order in which you do things. When I get a set of prints, I take time to look it over well, and make notes that include the steps (in machining order) needed to bring a given part to its completely machined state. Realize that some operations on a part have to be done before others. For some parts you will need to work out what surface of a part needs to be a datum surface on which to base all other cuts on that piece, and you have to do that surface first in order to complete all remaining machining on that part. Deciding just what that surface is, is usually left up to the builder. It will often coincide with a work holding surface. Dean ------- Re: Working from plans ? Posted by: "tonphil1960" tonphil1960x~xxaol.com Date: Mon Sep 7, 2009 1:36 pm ((PDT)) Thanks Stan and Dean, Everything you guys said makes alot of sense, I guess it will take practice like everything else we do. I am going to be reading plans for the next few days to get my bearings. I will have to work out workholding, clamping, and operations in general when I get the lathe and milling attachment. Hopefully I can get a drill press soon too. I am looking at a first engine. After I get comfortable turning with the lathe I will give one a shot. The LMS Oscillator, Elmers Tiny or #25 Wobbler, from what I have read on various forums these are good first engines. Tony ------- Re: Working from plans ? Posted by: "tonphil1960" tonphil1960x~xxaol.com Date: Mon Sep 7, 2009 3:12 pm ((PDT)) Looking at some plans I am stymied already, what is the reason for listing 2 hole dia's such as 0.188 0.193 one under the other as in LMS shops plan for the oscillator ? Not all the holes are listed this way just some of them. The rest of the plan I understand fairly well but this has me stumped. Thanks Tony ------- Re: Working from plans ? Posted by: "budman6899" wescott99x~xxhotmail.com Date: Mon Sep 7, 2009 3:20 pm ((PDT)) Tony, those indicate you must stay on, or in between those numbers for tolerancing purposes. Dave ------- Re: Working from plans ? Posted by: "Stan Stocker" skstockerx~xxcomcast.net Date: Mon Sep 7, 2009 6:33 pm ((PDT)) Hi Tony, I just pulled up the plans - assuming LMS is Little Machine Shop at least. Looks like we're on the same page anyway! The upper hole on the upright is 0.188 to 0.193. The intent is to have a free running but not sloppy fit for the 10-32 screw the cylinder swivels on. If the cylinder wanders too far, the steam and exhaust ports will not line up with the cylinder intake/exhaust hole, resulting in lost power or if severe a complete failure to run. Excessive free play would also allow the cylinder to rise up rather than having all the available energy pushing the piston down, wasting power. The lower hole must have a free running but low play fit for a piece of 1/4 inch shaft. The specs for the shaft allows 0.2500 +/- 0.0005, although they use the 0.2495/0.2505 representation. The interesting thing here is that they allow anywhere from half a thou to two and a half thou clearance depending how the tolerances stack. Sort of interesting to ponder as a learning exercise. I'd be inclined to think half a thou is too tight, but two and a half thou is getting close to a sloppy fit. In any event, the shaft should be a highly polished piece of 1/4 inch steel. Drill rod is probably the best bet, as one end needs to be threaded so dowel pins, drill blanks, or hardened precision ground shaft are all out. I'd be inclined to make a reamer from the same drill rod being used for the shaft so the fit would be good if I didn't have a 0.251 inch reamer on hand. The application indicates that the bore the shaft runs in should be a good finish, not some raggedy as drilled with a hardware store no name bit. I'm sort of surprised that on a beginners plan like this they didn't make a point of calling out that this hole is to be reamed to final size, not just drilled. Perhaps they wanted to make it easy to do, and didn't want to make folks buy additional tools. Looks like a fun little engine. If you make it and have fun, you might want to do one from castings such as the PM 3A. It's a tad larger and double acting, and while still a wobbler does add a nice blend of more involved steps without getting unreasonably difficult. It was my first engine kit and I learned a fair bit from it when I was getting started. Of course if you have Elmer's Engines and work your way through the entire set you will have a heck of a lot of knowledge when you're done. I'd sort of like to take that challenge on myself. One of these days... Hope this is helpful, and always have fun. Stan ------- Re: QCTP on an Atlas Craftsmen 12" x 24" Posted by: "wheezer" wheezer606x~xxverizon.net Date: Sun Jan 3, 2010 7:19 pm ((PST)) Rick Sparber wrote: > In case anyone is curious what a BXA size QCTP looks like on a > 12" x 24", you can see it here: > http://rick.sparber.org/QCTP.pdf Rick: In the QCTP pictures I see a ball-chain, a pulley and a digital caliper... hmmm what's that do and how is it hooked up? Got pics of that too? lance ------- Re: QCTP on an Atlas Craftsmen 12" x 24" Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Sun Jan 3, 2010 7:46 pm ((PST)) Lance: The nickel tour can be seen at http://rick.sparber.org/csDRO.pdf but the full story is scheduled to be published in Home Shop Machinist about mid year. The attachment lets me use a $15 Harbor Freight caliper to display diameter or radius by changing the angle of a bar. The display is parallel to my ways so is easy on my neck. Rick ------- [SherlineCNC] Re: A2Z extended base and precision lead screws expectations? Posted by: "William Rutiser" wruyahoo05x~xxcomcast.net Date: Wed Feb 3, 2010 10:06 am ((PST)) > Free motion has been reduced as much as possible and still > move smoothly but I can feel some. Glen: This message may be somewhat long-winded and pedantic. How much attention you should pay to these matters depends on how close you are pushing the accuracy limits of your equipment. Many surfaces on many parts don't matter all this much but I have enjoyed exploring these limits even tho it seems to mean getting a lot less finished. Your mileage may vary. If I understand correctly, your concern is that the edges of the table are not precisely parallel to the X-axis. Since you have measured the error, you know about it, and can allow for it in your setups. It's less than 0.001" per inch and its effects may well be negligible in many, particularly small, parts. Your setups may include elements with their own errors which either add or subtract from the edge error. For example, the fixed jaw of your vise may not be quite perpendicular to the sides of the base. When it's important, you should adjust the vise's position on the table so that it indicates parallel to the movement. Vises have been known to move, so you may want to check this from time to time. Other fixtures should be treated the same way. The important thing is that features on the part are properly aligned with each other. If it's sufficiently important, indicate on the part or material feature that is most important to the alignment of the next cut and adjust accordingly. As a general principle, measure as directly as possible without relying on any more interfaces than necessary. For example, when you use a square against the table edge, you are depending on: the edges relation to the slide, the squares relation to the edge( there could be a small chip or ding), the accuracy of the square, its relation to the base of the vise (more chips and dings), the manufactured relation of that edge of the base of the vise to its jaw, as well as the relation of the jaw to the part. By indicating directly on the part, you eliminate the effect of all those interfaces and may notice that the reference surface of the part isn't straight anyway. Another principle is to machine the important features in one setup if possible. While your indicator is out, check the vise jaws. Also check the Y axis alignment. Put the stock of a trusted square in your vise with the blade horizontal. Run the indicator along the edge of the stock and adjust vise position for zero deviation. Now run the indicator along the edge of the blade (moving the Y-axis). It may not be. The angle between the X and Y axis is machined into the middle layer of the base-saddle-table assembly. Check the Z-axis movement also. Clamp your square on the table with the blade vertical. Run the indicator up and down an edge. Repeat with the square in the other plane. Depending on which mill design you have, these may be adjustable. If not you can consider shims between the Z-axis and the mill base. But note that these measurements are not the same as the ones made by swinging the indicator around the spindle axis with the ball on the table. Check and adjust the spindle axis with respect to the table surface and the X-axis movement( set up your square in the vise so the edge of the blade shows zero deviation with X-axis movement. Place the spindle over the center of the edge and swing the ball from one side to the other. The difference between the two shows the error in the spindle axis to the X-axis. Try to record your measurements in a way that lets you refer to them in the future. For convenience, you may want to convert them to thousandths of an inch of deviation per inch of travel. (Privately, I refer to this as a milli-radian.) You will end up with a bunch of fairly small numbers. The question of how small is small enough or how big is too big may arise. Ask yourself these questions: If I make a part will I be able to measure the effect of the error? What effect will it have on the use of the part? Will my "customer", maybe yourself, notice the effect? or care about it? Can I overcome a bad effect when I machine the mating part? Can I fix it with a touch of a file, oil-stone, or sandpaper? Can I redesign the parts so the inaccuracies don't matter so much? Unless you are enjoying all this measurement, I suggest you get your machine together and make some non-critical parts. Remember this should be fun. Bill ------- Re: A2Z extended base and precision lead screws expectations? Posted by: "djmorrow2004" morrow2002x~xxlightspeed.ca Date: Wed Feb 3, 2010 11:40 am ((PST)) Maybe I'm the odd one out here but I have never used either the front or back edge of the X axis table as a reference point and so have never indicated there. To my way of thinking, I clamp my part or material down and, if necessary, indicate along that material or part. For all I know, my table may be oblong and it wouldn't matter. The only important mill surface to indicate for my purposes is the top surface to ensure squareness to the cutter. ------- Re: A2Z extended base and precision lead screws expectations? Posted by: "cnc4bill" wowenx~xxhotmail.com Date: Fri Feb 5, 2010 10:55 am ((PST)) I put the long A2Z tooling plate on the table and was able to use a dial indicator along the edge and adjust it to less than 1mil variation from end to end. For quick and quite accurate milling jobs I line up the workpiece or the vise (with a square) to the edge of the tooling plate and go. When I have checked this with a dial indicator on the workpiece itself, it has usually been within +/- 2 or 3 mils - good enough for many of my jobs. By measuring the workpiece itself I can usually get within +/- .001" on X, Y and Z with a dial indicator - which I think is quite good for a machine of this size and cost. Bill ------- DROs from Amazon... [sherline] Posted by: "Tom & Judy Bank" trbank1x~xxverizon.net Date: Wed May 26, 2010 7:08 am ((PDT)) Off and on we get posts about slide DROs made from electronic calipers. Now Amazon is offering these things ready to install. I just got the ad in an e-mail. Haven't bought it -- yet. Take a look at: http://www.amazon.com/dp/B003JULE4Y/ref=pe_54110_15633080_pe_vfe_t1 which is 12" long and: http://www.amazon.com/dp/B003JUII2A/ref=pe_54110_15633080_pe_vfe_t2 which is 24" long. They also offer a 6" version at: http://www.amazon.com/dp/B003JU46J4/ref=pe_54110_15633080_pe_vfe_t3 And a 35" version at: http://www.amazon.com/dp/B003JURUJM/ref=pe_54110_15633080_pe_vfe_t4 Prices range from $30.00 to $55.00. Note that the pictured 12" unit has three slides, but I think for the price you only get one. Let's see, $75.00 to equip a long bed lathe and $120 for a mill. Sound reasonable? The questions would be accuracy and whether it would gather swarf and destroy itself? Regards, Tom Bank ------- Re: DROs from Amazon... Posted by: "Rich Dean" toolman8x~xxcopper.net Date: Wed May 26, 2010 7:45 am ((PDT)) Tom, these have been available for years from several importers. The readouts can be had for vertical or horizontal. OTOH I have chopped jaws off several calipers to make DRO's for lathe saddle movement. The Harbor Fright units are ok, but too slow to update. I now use used Mitotoyo calipers from ebay and put the slow HF jobs on the quill on full size vertcal mills. Perfect for that. Unfortunately the bars and calipers resolution only do .0005" (.01mm) making lathe cross slide use no better than the dials. When turning to 10th's (.00001") I set up a 10ths reading DTI to see the final settings. RichD ------- Re: Dial indicators [atlas_craftsman] Posted by: "Starlight Tool Services Ltd" starlight_toolsx~xxtelus.net Date: Mon Jul 12, 2010 7:12 pm ((PDT)) > I'm looking to buy a dial indicator but don't really know about the difference in quality or what resolution I really need. Would a decent quality import dial indicator be sufficient for the tolerances on the 618? Or would it be worth it to buy a nice quality starret, B&S, Mitutoyo? Any help is appreciated :) < Start by reading through this website and the ones that accompany it. http://longislandindicator.com/p37.html Good readup on DI's and DTI's Walter ------- Re: Dial indicators Posted by: "EdwinB" n5kzwx~xxarrl.net Date: Mon Jul 12, 2010 9:35 pm ((PDT)) The other thing to bear in mind, Daniel, is that DTIs are best used for relative measurements, not absolute ones. That is to say if your DTI shows no movement as you hold it against the stock and rotate the spindle, then the spindle is centered; but, if you wanted to move the stock 0.010" off center in the chuck, you should not rely on the DTI to achieve the offset. A DI would be a better tool in this application. I have a number of Federal, Starett, Mitutoyo, and Yuasa DTIs and DIs. For centering stock in the 4-jaw, I'm most likely to grab my father's Bestest. Regards, Ed ------- Re: New file dial indicator [atlas_craftsman] Posted by: "c_h_a_r_t_n_y" mgibsonx~xxstny.rr.com Date: Mon Jul 12, 2010 1:06 pm ((PDT)) > File : /DialIndicator.jpg > Uploaded by : c_h_a_r_t_n_y > Description : Dial Indicator Holder > You can access this file at the URL: > http://groups.yahoo.com/group/atlas_craftsman/files/DialIndicator.jpg Pic over in files of my take on dial indicator setup. Includes tool bit centering gauge that works for dial indicator height gauge. Works for me, hope it is helpful for others. I do not use my magnetic holder. It attracts metal shavings, and magnetizes things that do not need to magnetized like tool bits and chuck jaws. (I have a home made de-magnetizer to fix that but works to just not magnetize things.) Happy Turning. chart ------- NOTE TO FILE: This next conversation takes an irreverent but amusing look at the confusion that occurs when different measurement systems collide. Say there is a metric plan but you have a machine graduated in imperial units. Or worse... there are many older measurement units out there, most of which we hopefully never encounter ;-) ------- Re: chuck too small [myfordlathes] Posted by: "dnaman43" mevagissyx~xxgmail.com Date: Sat Jul 31, 2010 2:35 pm ((PDT)) MikeD wrote: > and, - I hate mixed units! In one message we have "79mm" (3 1/8 > inch?) bar and "4 inches" chuck That doesn't sound particularly reasonable to me Mike. The lathe is an imperial machine and necessarily has imperial descriptors. At the same time many people choose to do their machining in metric units. Are you suggesting that, when discussing their machined parts in the context of the machine, they should convert all their metric dimensions to imperial? Or vice-versa ... e.g. a 101.6mm chuck? ------- Re: chuck too small Posted by: "Andrew Chapman" Chapmanadx~xxaol.com Date: Mon Aug 2, 2010 4:37 am ((PDT)) I use mixed units much of the time. I have a metric milling machine and an imperial lathe and use whatever units are appropriate for the work- piece, the machine or both. I seldom use barrels to measure anything but firkins can be handy sometimes. Kind regards, Andy Chapman ------- Re: chuck too small Posted by: "Tony Jeffree" tonyx~xxjeffree.co.uk Date: Mon Aug 2, 2010 5:30 am ((PDT)) I favour the FFF measurement system (Firkin, Furlong, Fortnight). Firkins are of course still useful for terribly important activities such as the purchase of barrels of beer. Regards, Tony ------- Re: chuck too small Posted by: "Alan Moore" a.j.moorex~xxbtinternet.com Date: Mon Aug 2, 2010 5:52 am ((PDT)) That sounds like a firkin good system. Alan ------- Re: chuck too small Posted by: "Tony Jeffree" tonyx~xxjeffree.co.uk Date: Mon Aug 2, 2010 9:17 am ((PDT)) A barrel of laughs too... Regards, Tony ------- Re: chuck too small Posted by: "Andrew Chapman" Chapmanadx~xxaol.com Date: Mon Aug 2, 2010 7:38 am ((PDT)) My lathe is graduated in units of 0.0000001262626263 furlongs. I have four chucks of three different sizes, one is 0.000505050505 furlongs diameter, two are 0.005366161616 chains diameter, and the fourth is 152,280 microns diameter. The conversion from furlongs to kilometres is very easy. It only takes 0.0000008267195767 fortnights to do it. AndyC ------- Re: Replacement precision dials/guages? [atlas_craftsman] Posted by: "Glenn N" sleykinx~xxcharter.net Date: Wed Jan 5, 2011 10:55 am ((PST)) He has the lathe compound set to ~30 so a .001 movement of the compound slide dial will remove .0005" or reduce the diameter by .001. I blued my dials and then filled the marks with gold rub so it has fantastic contrast (and looks bitchin). I was all set to make larger dials so I could read them better but the larger dials ala tallgrass can get in the way sometimes and my treated dials work great for me now. I used "Birchwood Casey's" cold blue gun blueing and the touch up pen to blue the dials in place and then rubbed in the "Treasure Gold" gilding wax that I bought at a hobby store. http://www.misterart.com/g746/Plaid-Treasure-Gold.htm http://birchwoodcasey.scaleslive.com/Finishing/FinishingDe tails.aspx?ProductID=63a37b33-e6cc-4129-9c38-ccf75bb7ec9d http://birchwoodcasey.scaleslive.com/Finishing/FinishingDe tails.aspx?ProductID=2eea6f1b-7376-423e-9fb2-ccacffc80906 Just some examples. I bought my supplies locally. ------- Re: Replacement precision dials/guages? Posted by: "c_h_a_r_t_n_y" mgibsonx~xxstny.rr.com Date: Wed Jan 5, 2011 2:26 pm ((PST)) Richard Hughson wrote: > Got it, thanks. I've got tiny dials and old eyes. This should help > a lot. Rick Re to Richard: Old eyes? I'm 71 and I use over the head magnifiers with prescription reading glasses to see those things. But I used a simple system. I cleaned my dials with acetone, then rubbed them with black paint pen. When dry, I sanded with 400G silicon carbide and waxed the od to prevent rust. Worked nice. First trial was on a Starrett, very old depth mike with bright chrome and graduation paint gone. Thus the sanding dulled the bright chrome and it worked quite well. Simple cheap, and such. Then did my dials on the lathe and my mike stop. Happy vision. chart ------- Re: Replacement precision dials/guages? Posted by: "mertnedp" pdentremx~xxforterie.com Date: Wed Jan 5, 2011 7:32 pm ((PST)) Why not make your own larger dials? I posted some pictures at http://wrx-now.tripod.com a while back. Click on Atlas Pictures for what I did for my cross slide dial. I have not issues with interference etc. It is resettable, and the best part, legible! ------- Re: Replacement precision dials/guages? Posted by: "Jon Elson" elsonx~xxpico-systems.com Date: Thu Jan 6, 2011 7:37 pm ((PST)) Jan 6, 2011, "caf182x~xxsbcglobal.net"wrote: >> You can also get more control by setting the compund over at an >> angle. An angle of 10:1 makes the 0.001" = 0.0001" on the dial. >> The big dials are nice but when you need a part and don't have them >> this will do the job. Setting the compound at an angle gives you finer adjustment of infeed, but it does nothing about the "spring" or deflection of the various lathe components. Jon ------- Re: Replacement precision dials/guages? Posted by: "mertnedp" pdentremx~xxforterie.com Date: Thu Jan 6, 2011 4:23 pm ((PST)) Dave Beckstrom wrote: > Nice job on the larger dials. How did you make the hash marks > and numbers on the dials? Basically it is the same way as making a keyway on the lathe. I used an old trick of laying out 100 divisions on the chuck by making a tape that gave me exactly 100 divisions using a CAD program. Took a couple of tries, but once I took a couple of strips and glued them together and then set it on the rim of my back plate and then used a sharp tool laid on its side to scribe on the back plate the 100 lines. I make every 10th one longer than the others. Then I chucked up the dial and scribed the matching lines on it. I simply placed a bent wire behind the back plate as an indicator. The numbers were just numbers stamps. Remember to lock the chuck by using back gears or whatever means that you like. You need no power to do this part of the job. You are just moving the carriage back and further via the hand wheel. ------- Re: Replacement precision dials/guages? Posted by: "caf182x~xxsbcglobal.net" Date: Fri Jan 7, 2011 11:52 am ((PST)) On 5 bears this page gives a great guide on getting high precision without a grinder at: www.5bears.com/cnc16.htm The combination of tool geometry and honing makes a surprising difference. Chris F ------- Re: Replacement precision dials/guages? Posted by: "Sue And Don" wilstyxx~xxtampabay.rr.com Date: Fri Jan 7, 2011 6:25 pm ((PST)) Well could not find the Same "gilding wax" but did find a type call "Rub-and-Buff" at a local art store. Worked Great! Never know where a great tips is going to come from. Dials and Protractor look great! Thanx for the great tip Glenn. ------- Re: Helps me [atlas_craftsman] Posted by: "Charley" holts001x~xxaol.com Date: Wed Jan 5, 2011 4:42 pm ((PST)) "Warren D." wrote: > Although this is my third lathe, I've been without one for quite sometime so I have to go back and do some relearning. I found something that helps me out a lot. There may be some reasons why no one else does it or that I shouldn't but it works for me. I set my compound at close to 61. I've checked this a couple of times and this is what I get. When I'm cutting I use the cross feed until I get close to the dimension that I want, then I start using the compound. When set at 61 it increases the cut by about half of what the cross feed does. And with trifocals I don't have to squint too bad. I too am going to try some of the other suggestions for making my dials easier to read. Thanks Warren < I haven't owned an Atlas lathe for many years. Therefore, I don't remember how the compound offset angle graduations are marked on the cross slide. If you set the compound at 84 degrees (actually 84 degrees 16 minutes), the graduations on the compound dial will equal .0001 inch. This is shown in "Technology of Machine Tools" McGraw-Hill, 1977, page 159. I don't know why they expressed it as 84 degrees, I've never own a lathe marked that way. This 84 degrees is relative to the center line of the lathe, like you are turning a very slight internal taper, dial end of compound is "out". This is harder to describe than I thought. If the lathe was a South Bend 10K you would set your compound at 6 degrees, because the compound itself is graduated 90-0-90, with the zero degree mark on the center line of the compound, 90 on each side. The Hardinge HLV-BK and some imported lathes have graduations on top of the cross slide, they too are marked 90-0-90 or 50-0-50, but with zero inline with the center line of the cross slide. You still set for 6 degrees, and the compliment is still 84. I hope you all can figure out what I mean, and I hope it helps. I have used this compound set up for twenty years, to fit bearings in housing without grinding. I need a drink now. Regards Charley ------- Re: Helps me Posted by: "c_h_a_r_t_n_y" mgibsonx~xxstny.rr.com Date: Wed Jan 5, 2011 6:45 pm ((PST)) Re to Charley: Atlas uses 90-0-90 degrees with straight ahead zero. And rounding a bit, as these old lathes were not that accurate when new, 60 degrees is .5:1, 78 degrees .2:1, and 84 degrees .1:1. And since Atlas uses one grad = 0.002" diameter, you can use 60 degrees to make the compound 1 grad to 0.001". That one I usually use. ps I did my own math for that so not guaranteed. chart ------- Re: Helps me Posted by: "Doc" n8as1x~xxaol.com Date: Wed Jan 5, 2011 8:31 pm ((PST)) FWIW .....w/ a SHARP hi speed bit you CAN take off a 1/2 thou ....bit must be sharpened & STONED ..latter is what is usually ignored...problem is ZEROING the bit on the work .....after this, w/ an unstoned bit, nothing happens w/ a 14 thou doc...so you put more on & pretty soon it will cut & you get ALL that you put on thereby turning undersize....taking successive cuts of a thou or so & measuring, may be easier than rezeroing ....this translates to multiple finish cuts most usually cut to a thou or so large & finish as they did when these lathes were designed 80 years ago, w/ file & paper, when absolute TRUTH is not required..... best wishes docn8as ------- Dial indicators [atlas_craftsman] Posted by: "Keith" brockklx~xxbellsouth.net Date: Wed Oct 12, 2011 7:32 am ((PDT)) Hi guys. I realize that you get what you pay for, but I have been watching ebay for a dial indicator, and with my budget (=0) I guess I am going to have to choose between old and possibly worn out, or new cheap Chinese. Here are a few I'm looking at: I've seen the mitutoyo before in training videos, so I'm going on the assumption that it's the Japanese equivalent of Starett. Suggestions? Is it worth it? Are the cheap ones as bad as I'm figuring they are? thanks Keith ------- Re: Dial indicators Posted by: "EdwinB" n5kzwx~xxarrl.net Date: Thu Oct 13, 2011 10:05 am ((PDT)) Keith, I see some confusion in your links. There are dial indicators, and dial test indicators. They are different devices and they are used differently. The dial indicator has a shaft that passes through the body of the instrument and out the other side. It is mainly used for absolute measurements, such as measuring how far you have moved the saddle. The dial test indicator (DTI) has a pivoting finger on the end of an arm that sticks out from the instrument. It is used for relative measurements like centering a shaft in a 4-jaw chuck. It really should not be used to make absolute measurements. If you are centering a smooth shaft, you could use a DI but a DTI is much easier to set up. Unless you need to center your work within a tenth (0.0001"), you will be happier with a DTI that has a 0.001" scale markings; it makes it a lot easier to dial in your work, especially if the work has any roughness to the surface. Regards, Ed ------- Re: Dial indicators Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Wed Oct 12, 2011 7:37 am ((PDT)) Anything will work if used carefully, what you're paying for is primarily in the smoothness of the action and how much slop there is in the mechanism. Mitutoyo is an excellent brand (I prefer it) but many others, Fowler, Interapid, Etalon, for example are also quite good. ------- Re: Dial indicators Posted by: "Terry Lund" terry.lundx~xxgmail.com Date: Wed Oct 12, 2011 8:24 am ((PDT)) I have one from ebay that looks just like the last one you listed, and it works OK but has a tendency to "stick" and I have to take the cover off and loosen the screws to "unstick it". The tip can't be adjusted into different positions like others (more expensive, I expect) that I have seen. Regards, Terry ------- Re: Dial indicators Posted by: "RG Sparber" rgsparberx~xxaol.com Date: Wed Oct 12, 2011 8:32 am ((PDT)) I'm no expert on DTI maintenance but have learned a few tricks. Carefully take the DTI apart and use a strong cleaner to get all old dried oil off of the gears. Do not get cleaner on the paper dial face or it will stain. If any WD40 ever got on the gears or pivots, you may have to carefully scrape with a knife. Then reassemble the gears such that you still have access to them. Use a light machine oil - dip a tooth pick into the oil and touch it to all pivot points and hubs. Only a tiny bit of oil is needed. Over oiling can lead to problems like sticking. Reassemble the DTI being careful to have the finger pivot snug but not tight. Watch how the springs engage the finger pivot. They should drop into slots. Test for repeatability using a surface plate and stand if you have them. Test both pushing and pulling on the finger. DTIs are all about repeatability, not absolute accuracy. Rick ------- Re: Dial indicators Posted by: "toolmaker48" toolmaker48x~xxyahoo.com Date: Wed Oct 12, 2011 10:02 am ((PDT)) Hi Keith, Your best bet is to visit the Long Island Indicator Service web site and see what they have to say about indicators. Mitutoyo is the equivalent of Starrett, only generally more expensive. Federal is top of the line. I'd go used. Robert ------- Re: Dial indicators Posted by: "Doc" n8as1x~xxaol.com Date: Wed Oct 12, 2011 1:22 pm ((PDT)) i have checked my mitutoyo one inch dial indicators against several of my china no names, not scientific, but against my lathe xslide dials,,,& for HSM use, i wud be hard pressed tp give an xtra nickel for a name brand ......TEST indiators may be a different thing & constant usage as well ......& yes,the ubiquitous one inch is better at increasing numbers the decreasing numbers...just MY thots... FWIW ...my $14 china dial indicator is only used for quick rough measuring ...they are even worse for internals, every one has needed stoning & adjustment of inside & depth indicators..and plus or minus one thou is not good enuf..for a lot of things .... as well as my china digital .....just not ridgid enuf & history when dropped......i much prefer the VERNIERS ......., & mics when more accuracy needed..... my starret dial indicator is way more ridgid & accurate than china ones.... but rarely used & never carried... since in my eighth decade, i am dropping stuff & that never used to happen ... best wishes docn8as [later message] sperm oil was used by watch makers, but good ole 3 in one oil seems to have less residuals used on my mics, even less than starret oil ... WD 40 will leave a residual wax ??? gum??? whatever ??, that causes MORE probllems ....slow DEATH for clock movements requiring complete teardown ..( thank you wife)...... ------- Re: Dial indicators Posted by: "Keith Brockmiller" brockklx~xxbellsouth.net Date: Wed Oct 12, 2011 1:38 pm ((PDT)) Hi Doc. I'm trying to picture using a mic to center the work in my lathe, and I'm coming up empty... As for verniers, are you referring to calipers? I can almost, kinda see that, with a solid fixture, and a good enough caliper... thanks all for the responses Keith ------- Re: Dial indicators Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Wed Oct 12, 2011 1:57 pm ((PDT)) He is talking about calipers as a tool in general, not related to centering work on the lathe. Vernier calipers use a vernier scale in lieu of a dial or digital readout of length. ------- Re: Dial indicators Posted by: "Doc" n8as1x~xxaol.com Date: Wed Oct 12, 2011 2:00 pm ((PDT)) so am i ! ...post was not intended for centering w/ a mike, nor a vernier, nor a dial caliper ...just my experience & preference regarding ......for centering a point in a 4 jaw, i use a pointed rod, opposite end is i spring loaded female center in t/stock center .....i use a one in dial indicator for checking runout of the rod, just back of the point .....read the total runout, center the indicator on 1/2 of that ...then adjust each PAIR of jaws to that zero ....twice & you shud be under a thou practice till you can do it in 2 minutes ..that was the standard 100 yrs go w/OUT an indicator, one can mount a double pointed rod so it can somehow wobble in the toolpost holder ..cause the holder is closer to the point to be indicated, the far end multiplies the runout ...when the point is still as the t.stock center, you are there ...OR you can buy the obsolete starret commercial one on ebay for an exhorbitant price.... #2 you can use the back of your tool bit against a pointed SPRINGY rod held in t/stock chuck near the point, & gage the runout by eye, finishing w/ a piece of cigarette paper between the two as a final gage & get less than a thou ..... #3 if you are centering the OD of a part, you dont need the ROD ...but the method applies best wishes docn8as ------- Re: Dial indicators Posted by: "JeffD" jefdaviesx~xxsbcglobal.net Date: Thu Oct 13, 2011 8:04 pm ((PDT)) Doc says "read the total runout, center the indicator on 1/2 of that... then adjust each PAIR of jaws to that zero." Thanks Doc -- that is what I am gonna try to memorize. Kindest regards, JJ Davies ------- Re: Dial indicators Posted by: "Steve" skadsmx~xxgmail.com Date: Thu Oct 13, 2011 5:27 am ((PDT)) I have picked up some sticky dial indicators at flea markets (last find was a pair of testmasters, 0.001 and 0.0001, for $10). What I do is flush them out with teflon lube. The lube is in a spray can, so I spray some in the cap and then drizzle the stuff through from the outside without disassembling. The liquid carrier disolves the dried muck and the teflon lubes the action. I haven't had any problems after doing that. Steve ------- Re: Dial indicators Posted by: "jworman" jwormanx~xxgmail.com Date: Thu Oct 13, 2011 8:51 am ((PDT)) You asked about dial indicators. I can't say if they are of comparable quality, but I believe so. Some time ago there was a post on some forum where a guy that worked for Boeing took his HF digital caliper down to the tool room for a lark. He asked them to see how bad they were. When he returned the tool room tech told him, there's nothing wrong with these. They pass all our tests. Would the dial indicators do so well, especially as most of them are analog. I don't know. ------- dial indicator Posted by: "Keith Brockmiller" brockklx~xxbellsouth.net Date: Thu Oct 13, 2011 11:42 am ((PDT)) Yeah, thanks for the input, guys. I was going to wait for a Toyo but I got an itchy trigger finger and bought one of the cheap ones instead. The consensus being, for hobby work, no need to break the bank. So thanks everyone ------- Re: Dial indicators Posted by: "Dallas" n5feex~xxnetzero.net Date: Fri Oct 14, 2011 10:14 am ((PDT)) I have always used zippo lighter fluid to clean dial indicators. At Rockwell where I used to work they had a metrology department that re-built and repaired dial indicators and measuring tools of all types. They used watch oil as a lubricant after cleaning movements. Small bottles are avaliable on Amazon. I have a little bottle I have used for 30 years, it does not take much, just a drop on a tooth pick point. Dallas ------- Re: Dial indicators Posted by: "gwelo62" gwelo62x~xxyahoo.com Date: Sat Oct 15, 2011 8:36 am ((PDT)) When I was a kid in sunny Rhodesia my mate's dad used to clean his watch by soaking it in benzene (no epa there). He claimed it left a residue that acted as a lubricant. I found that odd as benzene left my skin very dry if used to clean off oil. I don't know how a Chinese clock gauge face would stand up to benzene though! He also used a pin to put a drop of brake fluid onto the rubber diaphragms under the push-button switches of digital watches to stop the rubber going hard. I still do this myself. Cheers Ant ------- NOTE TO FILE: Little Machine Shop has a video showing how to use a wiggler and has other helpful videos. http://www.littlemachineshop.com/video/videos.php ------- [Topic is now really about improving visibility of machine dial markings.] Re: Compound nut mod [atlas_craftsman] Posted by: "Glenn N" sleykinx~xxcharter.net Date: Tue Dec 20, 2011 11:38 pm ((PST)) On December 19, 2011"xlpilot" wrote: > Glenn: This is OT, but were you the one that improved the contrast of your machine dials using "bluing" and "gold rub"? If so, can you tell us what kind of bluing and rub you used? Was the finish on your dials steel, or did it have a plating of some kind? < That would be me. I answered most of your question on the photos but I see more here. The bluing was Birchwood Casey's Super Blue cold bluing. "Treasure Gold" is the brand name of the rub on gilding. I found it in a craft store, normally used for antiquing/gilding lamps and such. The bluing by itself helps a lot for me but the gold numbers really pop out and it is easier to get the numbers to fill properly than most things I have used. The gold needs to be renewed now and than as oil seems to attack it but not fast. I have had it on the rulers I did for years and it is still looking new. They look much better than my pictures show. A good second place filler would be crayon if you can't find the gold rub. My dials were just plain steel that I polished some before bluing. Glenn ------- Re: Compound nut mod Posted by: "Glenn N" sleykinx~xxcharter.net Date: Thu Dec 22, 2011 10:10 am ((PST)) December 22, 2011 "nevetslleksah" wrote: > Glenn, just a thought, perhaps try spraying some clear acrylic on your dial IF that wouldn't cause the gold gilding to run and stand up to the oil and such. That is if you haven't tried that already .... < That is a good idea. I have had the treatment on there for about a year now and it is still good in most places but a good clear coat would extend that too. Thanks Glenn ------- Re: WAS Re: Compound nut mod, NOW: Enhancing contrast on dials Posted by: "Rexarino" rexarinox~xxgmail.com Date: Thu Dec 22, 2011 11:20 am ((PST)) FWIW, last year I went to the local drug store and asked for the cheapest white fingernail polish I could buy, had a bit of fun with the clerk, then spent my $1.96 and left. In the shop, I shook the jar, used the tiny brush to daub it onto all the lines and numerals, waited 10 minutes, then, moving quickly, I wiped the dial with a clean cotton rag. That left a thin white residue on the high spots, but coated the lines and numerals solid white. The next day, I wiped it down with an acetone wetted rag, moving quickly, which removed the white overcoat on the main part of the dial, but didn't affect the lines or numerals. Now, it's very easy to read and doesn't seem to rub off or stain. Anything you do to add contrast to the marks will make your life easier! Rex ------- handy gadget [myfordlathes] [but a great tip for any lathe] Posted by: "Hugh" hughmcwhinniex~xxntlworld.com Date: Fri Feb 10, 2012 7:08 am ((PST)) I watched a neat wee video on YouTube: http://youtu.be/tn7A9PqNftY So I decided to make one, the pictures of which are in a folder called HUGH. ------- NOTE TO FILE: Please read the safety cautions in this next message. And while you're on YouTube, check out some of the other nearby help videos that are listed on the right of the page. ------- Re: handy gadget Posted by: "Andrew Curl" methuselahx~xxntlworld.com Date: Fri Feb 10, 2012 9:42 am ((PST)) Works OK, most of the time a piece of brass strip over the tip of the tool will do the exact same thing. A piece of thin card can be used in the same way for brass and aluminum, although in all instances (and even if I were using a bearing instead) I pull the lathe over by hand, not under power. If the chuck is worn, starting inertia can rotate the chuck body leaving the scroll behind momentarily -- the jaws let go of the work, and can throw it. Andrew UK ------- Scribe or Dialing? [taigtools] Posted by: "Shane Adams" adamsch1x~xxyahoo.com Date: Sun Apr 1, 2012 4:41 pm ((PDT)) Do you prefer to go off your scribed lines for center drilling or do you prefer to do the location by counting hand wheel revolutions. Both? I've been marking with felt tip marker then scribing and then just eyeballing it. I have pretty decent eyesight still so it's worked out okay. I can usually get within a 0.001" on a good day. I have tried the other way and found myself screwing up on the count or not compensating for the slop etc. Just curious how others do it. Thanks! Shane http://www.fuper.com ~ https://github.com/adamsch1 ------- Re: Scribe or Dialing? Posted by: "Paul J. Ste. Marie" taigx~xxste-marie.org Date: Sun Apr 1, 2012 7:40 pm ((PDT)) If I'm going for accuracy, I'll use an edge finder and the dials. Scribing the location is important, since that's what catches miscounts. The trick I use for backlash is to always approach the measurement in the same direction. I'll put a + or - after the number when I write it down to indicate which way I should be going. ------- Re: Scribe or Dialing? Posted by: "Dean" deanofidx~xxyahoo.com Date: Sun Apr 1, 2012 8:08 pm ((PDT)) I use the dials. Then I don't have to wait for a good day. ;) There is no slop unless you're working both ways on one axis. Avoid that, and the dials will get you where you want to be. If I have to do complicated hole patterns, I mark out in the normal way just to have reference marks, but I don't use them to try to eyeball where a hole goes, and I always start the dials at a zero point so I have a start reference. Working to mark out lines is fine for clearance holes, but not if you need everything to really be "on". ------- Re: Scribe or Dialing? Posted by: "alighazizadeh" alighazizadehx~xxaol.com Date: Mon Apr 2, 2012 2:54 am ((PDT)) Hi Shane: Depends on what you are trying to do. For the sake of the argument let's say you are building a model engine. From my point of view scribing doesn't at the best of times provide any real accuracy. In my case it is about 0.002" at very best and often worse. For real accuracy you need to indicate, find the edges and then dial in using the hand wheels or better with DRO. Although if you choose to dial in using the hand wheels you still have the problem of the inaccuracy of the lead screws, but for short distances the errors are not important. If however you are trying drill holes in a plate for mounting an electric motor or similar task, the scribing method is more than satisfactory. Regards, A.G ------- Re: Scribe or Dialing? Posted by: "Will Schmit" anchornmx~xxyahoo.com Date: Wed Apr 4, 2012 4:37 pm ((PDT)) The trick for backlash is to not have any. I use the dial method. I have used the scribe and punch method too, but I have never been satisfied with the results. I set up a plate with multiple drilled/tapped holes, out of 20 holes, I had 3 that I couldn't get to line up with the bolts. I rebored the plate by counting, and it worked perfectly. ------- Re: Scribe or Dialing? Posted by: "Shane Adams" adamsch1x~xxyahoo.com Date: Mon Apr 9, 2012 4:01 pm ((PDT)) Okay -- I tried the scribe and dial method. It is how I will be doing things in the future. I just calculate the number of turns on the dial and then if I am dialing clockwise or counter-clockwise. I noticed in a recent attempt that I had two errors [dialing didn't place the center drill over the right location] due to a misalignment in the vise. So what I do now is: Use an edge finder and then calculate the number of turns to locate for the one axis. Then do the same for the second axis. I was very happy to see my holes line up perfectly on a couple of pieces I laid on this way. I now realize I was never getting .001 by eyeballing, probably the error was much larger. I also went and purchased an extra large Sharpie, like this one here, but I got mine in blue at an art supply shop for 3 bucks or so http://shop.hobbylobby.com/products/magnum-44-marker-132159/ Works really well, and inexpensive. Thanks! Shane ------- Re: Scribe or Dialing? Posted by: "Dean" deanofidx~xxyahoo.com Date: Mon Apr 9, 2012 11:08 pm ((PDT)) Glad to hear of your success, Shane! I use a big blue marker, like a Sharpie, too. Pretty handy for those times you don't feel like sloshing Dyekem all over the piece. Dean ------- Mauser vernier [atlas_craftsman] Posted by: "Guenther P" paulguenterx~xxatt.net Date: Tue Apr 3, 2012 5:11 am ((PDT)) I have a Mauser vernier that i need a lens for. Does any one know where i could get one. I looked all types of lenses and watch crystals. So far no luck. The lens is 1 5/16 in Dia. I e-mailed Mauser and the reply was they dont make them anymore. Thanks GP ------- Re: Mauser vernier Posted by: "John Bates" reproturnx~xxbigpond.com Date: Tue Apr 3, 2012 5:50 am ((PDT)) Hi GP. Try G-S Suplies in USA http://www.gssupplies.com/custom_watch.html Nice to deal with and lots of different size crystals to suit dial indicators etc. Hope you find yours. Cheerio John B Sydney, Australia ------- Re: Mauser vernier Posted by: "Bob Robinson" robinx~xxzzzip.net Date: Tue Apr 3, 2012 5:50 am ((PDT)) I carry a folding pocket magnifier. The lens is 1 13/16 inch diameter. Since it is plastic, it should be easy to grind to size. But then the edge might be too thick for your situation. Even then, the edge could be ground to a taper. Bob ------- Re: Mauser vernier Posted by: "Russ Kepler" russx~xxkepler-eng.com Date: Tue Apr 3, 2012 6:51 am ((PDT)) Try these guys, if they don't have one they might know who would: http://www.longislandindicator.com ------- Re: Mauser vernier Posted by: "Jim" halbert____1x~xxmsn.com Date: Tue Apr 3, 2012 9:45 am ((PDT)) I made a replacement lens from a juice bottle the hard clear plastic; it worked very well and was the same thickness as the original. ------- Re: Mauser vernier Posted by: "Jon Elson" elsonx~xxpico-systems.com Date: Tue Apr 3, 2012 10:05 am ((PDT)) I turned one out of Plexiglas, made the back side hollow to clear the pointer. Then I polished it with polishing compound on the lathe. Superglue can be used to attach the plastic to a faced piece of steel. Jon ------- [atlas_craftsman] new article: An Ultra Low Tech, Low Cost Electronic Edge Finder Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Mon May 28, 2012 11:08 am ((PDT)) This article presents a very simple method of having the Electronic Edge Finder function by using a commonly available continuity checker and a few bits from around the shop. It should work on any mill and any lathe. In spite of its simplicity, you can detect the touch-down of the cutter with a repeatability of better than 0.0002". If you are interested, please see http://rick.sparber.org/LTEEF.pdf Your comments and questions are welcome. All of us are smarter than any one of us. For the full index of my articles, see rick.sparber.org. Rick ------- [atlas_craftsman] (no subject) [In response to conversations about electronic edge-finding] Posted by: "jo barden" jobarden422x~xxmsn.com Date: Wed Jun 6, 2012 11:03 am ((PDT)) Whilst I think it is great to think about these sorts of things but an old trick I was once shown is to use a cigarette paper and stick to the surface and when the cutters starts to tear/mark the paper you are a thou off from the work. Just a thought. Jon ------- (no subject) Posted by: "Bob Christie" bobx~xxrcredd.com Date: Wed Jun 6, 2012 6:22 pm ((PDT)) We used the cigarette paper for precision work and had one of the shop rats saw old readers digest into 1/2 inch wide "books" so we could use them for general touch off. They were .003" thick and real handy. Single ply butt wipe was used with Hi-Spot to check the parting lines of injection mold. ------- [Has now become a conversation about metric dimensioned plans and an imperial machine, and vice versa.] Re: Motor choices for the Taig lathe [taigtools] Posted by: "Lewis Hein" lheinx~xxvcn.com Date: Wed Jul 11, 2012 6:07 am ((PDT)) On July 10, 2012, Douglas Vogt wrote: > It shouldn't be a problem as long as you have a calculator handy. I have the opposite situation here in the US: a metric lathe and imperial plans for clocks. If you are following plans, convert all the imperial measurements to metric for the drawing. One problem you may encounter is the difference in stock sizes. If a part calls for a certain diameter in inches, for example, you may have to go to a larger metric size and turn it down. < Another trick is to get a set of imperial plans, and then declare that 1/32 of an inch is 1mm. That way, a 1/16" drill bit becomes 2mm, a 13/32" drill bit becomes 13mm and so on. Of course, your projects will turn out a little bigger than the plans specify, but in some cases that shouldn't be a problem. Just my $0.02 Lewis Hein Pens, plans and projects online at www.heinfamilyenterprises.com/ppp p.s. This also seems a good time to mention that I have an Inch/ metric converter on my site http://www.heinfamilyenterprises.com/ppp/imet.php?em=1 Hope it is useful. ------- Re: Motor choices for the Taig lathe Posted by: "Paul J. Ste. Marie" taigx~xxste-marie.org Date: Wed Jul 11, 2012 4:24 pm ((PDT)) On 7/11/2012 6:07 AM, Lewis Hein wrote: > Another trick is to get a set of imperial plans, and then declare > that 1/32 of an inch is 1mm Or that 1" equals 25mm exactly, which gives nice decimal values in both directions. Likewise, M2.5 = 3-48, M3 = 4-40, M3.5 = 6-40, M4 = 8-32, M5 = 10-32, M6 = 1/4-20, M8 = 5/16-24, and M10 = 3/8-24. ------- Locate the center of an existing hole [SherlineCNC] Posted by: "Tom Wade" tomx~xxwade.name Date: Sat Aug 4, 2012 1:47 pm ((PDT)) Recently made a bellcrank for my new 1/8 scale locomotive. Didn't know, and couldn't directly measure the length or location of the holes on the input linkage on the transmission. Took a guess, and built a bellcrank to hook the linear actuator to the input linkage. Now I have too much travel at the linkage, so need to relocate the holes in the bell crank. Anyone know an easy, quick way to locate the existing holes after I clamp the part to the mill table? I have a wobbler set and an edge finder. Don't know how to use either one to find the center of a hole. Thanks Tom Wade Hope, Indiana ------- Re: Locate the center of an existing hole Posted by: "Martin Dobbins" trainnutzx~xxyahoo.com Date: Sat Aug 4, 2012 2:08 pm ((PDT)) Hi Tom, You don't mention how large the existing holes are, would they be large enough to admit the tip of a DTI? If they are you can tram your way into the hole by rotating the DTI in the spindle, like this: http://awtarlab3.engin.umich.edu/wiki/index.php/S2T1_:_Finding_the_Cen ter_of_a_Pre-Existing_Hole It is possible to do this with an edge finder with a conical end but not nearly so accurate, let us know if you need some further help with that. Martin ------- Re: Locate the center of an existing hole Posted by: "Tom Wade" tomx~xxwade.name Date: Sat Aug 4, 2012 2:18 pm ((PDT)) The existing hole is threaded for a 1/4 - 28 bolt. Don't know if I've got a tip small enough on my DTI. Just found a video showing how to find the center of a round shaft or tube using a wobbler. Think I'll just cut the head off a bolt and screw it in the hole, then use the wobbler to find the center of the bolt. http://www.youtube.com/watch?v=SsP6u6CYxRk Tom ------- Re: Locate the center of an existing hole Posted by: "Martin Dobbins" trainnutzx~xxyahoo.com Date: Sat Aug 4, 2012 2:30 pm ((PDT)) Tom, That makes sense but you'll get more accurate results if you find the center of the bolt with your DTI. Martin ------- Re: Locate the center of an existing hole Posted by: "Tom Wade" tomx~xxwade.name Date: Sat Aug 4, 2012 2:55 pm ((PDT)) No doubt about that. However, since I'm still guessing about where the new holes go, I just need enough accuracy to know where I'm putting the new holes. Want to keep an adequate distance between the centers of the old holes and the centers of the new holes. Tom ------- Re: Locate the center of an existing hole Posted by: "Ron Thompson" ronx~xxourcadguy.com Date: Sat Aug 4, 2012 4:07 pm ((PDT)) In that case, chuck a needle or a scribe and eyeball it from two directions. Or you could cheat. Use a headless bolt in the existing hole and a drill chuck or collet. Clamp it in the vise, then bolt the vise to the table. If the hole weren't threaded, I'd locate it with a countersink in the chuck. These methods will get you within a few thou if you are careful. Ron Thompson On the Beautiful Florida Space Coast right beside the Kennedy Space Center, USA http://www.plansandprojects.com/My%20Machines/PrusaMendel2012-1/ http://www.plansandprojects.com My hobby pages are here: http://www.plansandprojects.com/My%20Machines/ Visit the castinghobby FAQ: http://castinghobbyfaq.bareboogerhost.com/ ------- Re: Locate the center of an existing hole Posted by: "Tom Wade" tomx~xxwade.name Date: Sat Aug 4, 2012 9:06 pm ((PDT)) Turns out that despite my faulty memory, the hole was NOT threaded, and had a clevis pin in it. I put a headless pin in the hole and located it with the wiggler. First time I'd ever used one, and it worked great. May not be to a millionth on an inch, but don't really care, in this instance. Now the bellcrank is installed, and we have free travel in the hydrostat linkage at both extremes of travel. Case closed for tonight. Lots more work to do on other systems. Tom ------- fed up with digital vernier Caliper [myfordlathes] Posted by: "colin.murray7x~xxbtinternet.com" Date: Fri Oct 5, 2012 2:20 pm ((PDT)) As in the title I am sick of this el cheap thing that I have; it keeps changing reading and I have to be extra careful and check and recheck. Can you guys tell me what is a good reliable vernier calliper please? I do not have unlimited resources so sensible prices are a must but not el cheap again. Regards Col ------- Re: fed up with digital vernier Caliper Posted by: "Robert Mitchell" rmm200x~xxyahoo.com Date: Fri Oct 5, 2012 2:40 pm ((PDT)) If you go cheap again, buy local so you can take it back easily. Harbor Freight has a 6" for $24.95 (absolute, metric, etc.) now that will be as accurate as a far more expensive one - just not made as well. For quality, you can't beat Mitutoyo. Amazon has the 6" at $115.00 currently. I have used one of these for years and love it. Note - calipers are really not for precision work - but they sure are handy. Robert Mitchell ------- Re: fed up with digital vernier Caliper Posted by: "Andrew Curl" methuselahx~xxntlworld.com Date: Fri Oct 5, 2012 9:50 pm ((PDT)) Digital calipers do not have a vernier scale. The best reliable vernier at a good price is a vernier. For the digital stuff, you get what you pay for, but that said, my own is a Mitutoyo "absolute", and while it cost me half a week's wages, it's still going just fine after seventeen years of daily use, and only one battery change too. That said though, it is the second of its type I have owned, the first skipped out a thou at about 3", and after checking with slip gauges it was exchanged as faulty after 3 days use. Calipers are often said to be regarded only as a guide. Sometimes, however, it is simply not possible to get a micrometer "in". Accurate readings can be obtained if you refrain from holding the calipers by the scale and moving the lower jaw with your thumb, one handed; instead hold the calipers by the scale with one hand and close the jaws across the workpiece with the other -- this eliminates flex and will give a true reading. Cheap tools are a false economy, and working with them makes life a misery. Stick with brands you have heard of, and check digital gear against slips as the first task after it comes out of the box. Short term, precision engineering ain't cheap, longer term it is, as you only tend to buy a lot of -good- tools, once. Andrew UK ------- Re: fed up with digital vernier Caliper Posted by: "Cliff Coggin" clifford.cogginx~xxvirgin.net Date: Sat Oct 6, 2012 4:05 am ((PDT)) You can have quality or you can have cheap. Take your pick because you can't have both. I bought a 4" digital (not vernier) caliper from Arc Euro Trade for about £10, and I'm delighted with it, though I must point out that my need is for relative dimensions not absolute dimensions. Occasionally I get the numbers to flicker up and down at certain points like yours, but that is easily solved by dismantling and cleaning the sensor and slide. Cliff Coggin Kent UK ------- Re: fed up with digital vernier Caliper Posted by: "Kevin" tadpolex~xxbtinternet.com Date: Sat Oct 6, 2012 6:37 am ((PDT)) Colin, I'd never want to put someone off from buying real quality tools, but before you get your Mitutoyo it might just be worth seeing if you can dismantle your existing caliper and give it a clean. Might help, nothing to lose. Kevin, NW England, UK ------- Re: fed up with digital vernier Caliper Posted by: "colin.murray7x~xxbtinternet.com" Date: Sat Oct 6, 2012 4:07 am ((PDT)) Thanks to you all for advice, I know you get what you pay for but not in every circumstance. Mitutoyo it will be then. Col ------- Re: fed up with digital vernier Caliper Posted by: "Barry Kneller" bkba09515x~xxblueyonder.co.uk Date: Sun Oct 7, 2012 8:01 am ((PDT)) Sorry if I'm stating the obvious, but do you always clean the measuring faces every time you check the zero? (I'm sure you do,,,) Collected wisdom suggests using a piece of paper between the faces. Close the caliper (or micrometer) lightly onto the paper and pull the paper out without opening it up; as I can seldom find a piece of clean paper in my workshop I just use my shirt collar, 'er downstairs can't understand why I get these parallel dirty lines on my shirts. ------- Re: fed up with digital vernier Caliper Posted by: "Haydut1200" haydut1200x~xxgooglemail.com Date: Sun Oct 7, 2012 8:20 am ((PDT)) I've found these cheap digital calipers can easily get magnetised, even though they are supposed to be stainless steel, and tiny, easily missed pieces of swarf can be left behind. I've found that cleaning with a paint brush, but using a flicking action rather than a brushing action, seems to be the best way to clean them. Works for me anyway. I also use my 100 watt soldering iron to de-magnetise mine. Martin ------- Re: fed up with digital vernier Caliper Posted by: "Barry Kneller" bkba09515x~xxblueyonder.co.uk Date: Sun Oct 7, 2012 10:56 am ((PDT)) Funny you should mention that - I've recently started using a powerful, polythene bag covered magnet to help clear swarf, just noticed (today) that my Mitotoyo calipers have become magnetised. Thanks for that good tip with the soldering iron - I have an old tape head de-magnetiser somewhere - I'll have to dig it out and try it. Barry ------- Re: fed up with digital vernier Caliper Posted by: "Robert Mitchell" rmm200x~xxyahoo.com Date: Sun Oct 7, 2012 8:39 am ((PDT)) Standard technique I use on mine is to close the jaws on a piece of fabric, and pull the fabric out. Does a good job of wiping off bits of swarf that prevent a zero reading. ------- Re: fed up with digital vernier Caliper Posted by: "HG" hgx~xxallthemunros.com Date: Sun Oct 7, 2012 8:20 am ((PDT)) I've been using dial calipers, metric and imperial versions, for some years now, after I found micrometers and verniers tricky to read, even with my normal reading prescription. I tried digital calipers, but mine seemed to get through batteries rather fast. If I need greater accuracy, I use a micrometer and a lens. But the calipers are pretty good. I'm surprised no one else has mentioned them! Henry ------- Re: fed up with digital vernier Caliper Posted by: "c j.s" callinicus1953x~xxyahoo.co.uk Date: Sun Oct 7, 2012 11:10 am ((PDT)) Hi Henry, I too use a dial caliper in preference to a Digital, although the latter's instant conversion for Imp/Metric does have advantages. I use Mitotoyo because of the very easy resetting should they get knocked and lose zero. That's what the little bit of wire with the square on the end is for, for those that don't know. CJ(UK) ------- Re: fed up with digital vernier Caliper Posted by: "Cliff Coggin" clifford.cogginx~xxvirgin.net Date: Sun Oct 7, 2012 9:17 am ((PDT)) Not wishing to teach Granny how to suck eggs, but do you clean the jaws every time you take a measurement? I find 0.02 mm change in zero reading is easily caused by invisible specks of dirt. Cliff Coggin Kent UK ------- Re: fed up with digital vernier Caliper Posted by: "c j.s" callinicus1953x~xxyahoo.co.uk Date: Mon Oct 8, 2012 6:47 am ((PDT)) > We have Mitotoyo stuff at work (not with me here at the moment). What is this little bit of wire???????? Explanation PLEASE--------I’ve never noticed it Doooohhhhh Bob < Hi Bob, I wondered if someone would ask, as it is it seems not generally known how to reset zero without pulling the thing apart. I don't know if this is how you are meant to do it but it works for me. First remove the screw and black bit of plastic that is at the six o'clock position, then slide the moveable jaw till the needle is at zero. Now the clever bit, insert the wire into the small hole which the black plastic covered, it is just under the back of the dial, and gently push. While you are pushing you are taking the drive gear out of engagement so you can slide the moveable jaw back to the closed position and hey presto your caliper is reset. If you have lost your bit of wire, it is about 18-24thou and about 1 1/4" long with a square of about a 1/4" square bent at the end to form a handle. If this does not make sense please ask again. CJ(UK) ------- Surface Plate question [Metal_Shapers] Posted by: "dkirk_4" dkirk4x~xxgmail.com Date: Mon Oct 22, 2012 8:14 am ((PDT)) Gentlemen, I'm planning on getting a surface plate, so I'll have at least one flat reference. Grizzly has Grade B which they say is within .00015" bilateral accuracy. I'm trying to figure out what that means. Does that mean the larger the plate, the flatter it is? Because they don't specify per inch or per foot or anything. Does it mean it's within .00015 between the top and the bottom, in which case the two sides are parallel, or if you cut the top in half, each side would only be off by a maximum of .00015 which is another way of saying a maximum deviation of .0003, which I've seen other Grade B granite surface plates spec'd at? And even if it is .0003, is this flat enough to check the bottoms of the ram dovetails for instance? Seems to me it would be. Is there a top and a bottom? Or are both the top and bottom flat, just not necessarily parallel? I need to know, because I'm going to need to pick it up from the store the way it's going to arrive at the house. I have a cart I can put it on, then push it into the back of a van and the legs fold up. Then they pop back down for the ride into the garage. So I'll need it bottom up so I can put the feet on it, and then I'll only have to flip it once to put it on a stand. Although, I'm thinking maybe I should just put it on a bench and put a plywood cover on it so it doesn't become a work surface. Either way it's 160 lbs. so I won't be flipping this over by myself and I'd like to do it once if possible. The previous owner of the shaper said he was a machinist, and he scraped all the ways in, and there are indeed scraping marks on all the ways that the table rides on, just not on the ram dovetails or ways. I'd just like to check some of that before I put it all back together. See if anything is seriously twisted, or if the bushings line up. The only thing I found on the web was a machinist on a telescope making forum saying that this was flat enough to check a lens grinding operation on, so I would assume it's fine for this. Just wanted to get some opinions from other people who know more than I do. I appreciate the responses so far. Bear with me please, I'd like to have this up and running by summer. "-) ------- Re: Surface Plate question Posted by: "john forney" jwforneyx~xxmsn.com Date: Mon Oct 22, 2012 9:45 am ((PDT)) Hi Kirk, a surface plate is only processed on one side, the top being the ground in surface. Bilateral accuracy means the surface is within .00015" from side to side, top to bottom, and no more than that at any point on the surface. About as flat as one can need in the home shop. In use, protect the surface when not being used. Being very careful of dropping anything on it as it can chip. In use don't slide ANYTHING across the surface as it can abrade or scratch, even your measuring tools. After all, it's a stone. Just a very accurate one. John ------- Re: Surface Plate question Posted by: "Nelson Collar" nel2larx~xxyahoo.com Date: Mon Oct 22, 2012 9:50 am ((PDT)) D Kirk: Save your money and buy a surface plate with a "B" grade. The "AA" is a laboratory grade: For high precision operations in consistent temperature gauging rooms and metrology departments. The "A" grade Inspection Grade: For general use in quality control areas. The "B" is a Toolroom Grade: For shop work and production checking. Those are the grades and a "B" will be sufficient. The surface is a fragile thing and if anything is dropped on it, it might crack it. Nelson Collar ------- Re: Surface Plate question Posted by: "Ondrej Krejci" okrejcix~xxyahoo.com Date: Mon Oct 22, 2012 1:13 pm ((PDT)) Bilateral accuracy within 0.00015" means that any two lines on the top, flat lapped side, there's only one good side, will be between two parallel planes spaced 0.00015" apart. As for bigger, being flatter, the answer is no, because: The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula: Laboratory Grade AA = (40 + diagonal squared/25) x .000001" (unilateral) Inspection Grade A = Laboratory Grade AA x 2 Tool Room Grade B = Laboratory Grade AA x 4. per http://www.tru-stone.com/pages/faq.asp Pertaining to set-up, I got my 18" x 20" plate in the basement, assembled the stand, put the stand on its side, loaded the plate, and lastly, squatted the whole deal with the wife. ------- Re: Surface Plate question Posted by: "chrisw" in2steamx~xxwi.rr.com Date: Tue Oct 23, 2012 10:56 am ((PDT)) I would not even order it from grizzly I got my b grade from woodcraft (if you have one near) which had it in stock, the shipping alone from grizzly paid for the plate I got. I took it to work when I had access to a nice QC lab and had them run a point check and it came up better then spec (although they complained about leveling it). I made a nice dovetail gauge for my Logans with it and the 7b a few years ago and it was much easier then using my 80# portable cast iron one in a vise. I also checked the 7b's ram, I almost wish had not afterwards though, it got put back on and marked onto the to do list. Either way it is way more accurate then any shaper ever made. I had a nice steel cover that happen to fit right over it, otherwise it will gather things on top of it and get damaged. I would not get too concerned about the dovetails on the ram; they take most of the wear and no shaper ever built is so accurate on the ram that scraping it will help for very long. The table ways, yes for sure check them. If you are not practiced at scraping, make some test pieces and then a few small plates or gauges with it. Best Regards, Chris ------- Re: Surface Plate question Posted by: "epa_iii" palciatorex~xxgt.rr.com Date: Tue Oct 23, 2012 11:29 am ((PDT)) The term "bilateral accuracy" means that all points on the surface lie between two parallel planes that are the stated distance apart. It is twice the amount that would be stated as a +/- figure so it represents the maximum distance between the highest and lowest point on the surface. It is also the same as a TIR (Total Indicator Readout) reading. That is the total amount that an indicator would change by when moved between any two points on the surface. +/- 0.0001" = 0.0002" bilateral accuracy and 0.0002" TIR = 0.0002" bilateral accuracy http://www.tru-stone.com/pages/smp.asp I believe the term "bilateral" refers to the fact that it is measured as the sum of both the + and the - part of the deviation. So it includes the error in both or two directions hence it is, bilateral or two directional. It has absolutely nothing to do with the bottom of the stone. As for using it to check the inside angles on your shaper, it will not get into the internal angles. You WILL need a straight edge with a matching or smaller angle. You can either buy one or make one. In either case, you can check that straight edge against the surface plate. As for the comment about the accuracy needed when grinding lenses, I have ground a telescope mirror and at no point in that process did I need or use a surface plate. The accuracy of optical surfaces, at least those used in astronomy, is at least an order of magnitude greater than even the lab grade surface plates. An optical flat is in the range of 10 or 20 millionths or less. A crudely made pin hole tester can measure a telescope mirror to such accuracies. So I have no idea where a surface plate would be used in lens or mirror grinding. Perhaps in the rough grinding stage? Oh, one more observation. Flipping a 160 pound plate over only requires half that much lifting force or 80 pounds if you leave one edge on the work bench. You only lift the full weight if you take it off the bench. I could flip it with my bad back. Paul A. ------- Tail Stock DRO [myfordlathes] Posted by: "Lane" lane45acpx~xxyahoo.co.uk Date: Sun Nov 4, 2012 1:15 pm ((PST)) I wanted to add a DRO unit to my ML7´s tailstock without machining, drilling, tapping, etc. into the original metal. Basically I machined two rings out of aluminum to attach to the tailstock, one fixed at the rear, fixed by set screws. The one in front is attached to the tailstock barrel, fixed by a set screw also. The horizontal digital readout bar from arc euro trade needed to be cut down to fit. Not a problem because of the limited tailstock travel. I loaded a few photos in the album "Lane´s tailstock DRO". ------- Re: Tail Stock DRO Posted by: "alighazizadeh" alighazizadehx~xxaol.com Date: Sun Nov 4, 2012 1:26 pm ((PST)) Hi, That is a great idea, I have just about done something similar for my Taig lathe. I have a 4" dro that I think would suit this to a T. Many thanks and regards, A.G ------- Re: Tail Stock DRO Posted by: "Barry Forrest" 2barryforrestx~xxtiscali.co.uk Date: Mon Nov 5, 2012 7:38 am ((PST)) Can I ask if anyone has had any problems with the DRO maintaining its accuracy as you move the tailstock in and out? I made a similar attachment between the rear of the saddle and a "saddle-stop" mounted behind the saddle, using an adapted digital vernier. See photo in Barry's Photos. I don't have a picture of the vernier attached but you can probably picture how it was mounted using the clip on top of the saddle stop. It seemed to work well but occasionally and, more problematic, would misread so was not reliable. At present I have discontinued its use. It may be that I need to purchase a proper DRO or a more expensive vernier to adapt. [BTW it worked fine as a vernier]. Any experience of similar problems would be of interest to me. Thanks Barry ------- Re: Tail Stock DRO Posted by: "Paul Kennedy" clankennedy2004x~xxyahoo.co.uk Date: Mon Nov 5, 2012 8:54 am ((PST)) Did you give it a clean and replace the battery ? ------- Re: Tail Stock DRO Posted by: "Barry Forrest" 2barryforrestx~xxtiscali.co.uk Date: Mon Nov 5, 2012 10:55 am ((PST)) Paul Thanks for the suggestion, but what more can I say... Yes. (And that battery, which will definitely need a change with the cold weather coming, is still going in another Digital Vernier!) Barry ------- Re: Tail Stock DRO Posted by: "Lane Brown" lane45acpx~xxyahoo.co.uk Date: Mon Nov 5, 2012 2:26 pm ((PST)) Can you explain a bit more in detail as to what is going on when you say the DRO maintaining its accuracy? Issues that come to mind are loose parts or "play" in the setup. Non-parallel setup, as in the vernier not in exact tracking on the same plane as the tailstock barrel. -------- Re: Tail Stock DRO Posted by: "alighazizadeh" alighazizadehx~xxaol.com Date: Mon Nov 5, 2012 2:50 pm ((PST)) Hi, The issues with accuracy of DROs that I have had are usually to do with dirt or oil on the track, misalignment of track to the axis of motion and quite often the holding bracket that has worked itself loose. Some of the older designs also do not respond too well to very rapid movements, not relevant to the Myford tail stock but important with cnc mills and lathes if fitted with DROs. Regards, A.G ------- Re: Tail Stock DRO Posted by: "Martin Slater" mfslaterx~xxgmail.com Date: Tue Nov 6, 2012 3:04 am ((PST)) Hi Listmates Why all this enthusiasm for frequently inaccurate, expensive, battery-swallowing cheapo digital verniers? Why not mount mechanical, no running costs, dial gauges with a 2" or more range? I fit one to my Super 7 tailstock with a magnetic bracket and a long actuating arm clamped to the tailstock barrel (this stays in place). On my mill, I use the same dial gauge wherever needed with stops on magnetic brackets. One-off cost and it doesn't go south on you on a Sunday morning. Only problem is that the streamlined shape of the Super 7's tailstock body is not conducive to easy mounting (unlike the squared-off silhouette tailstocks fitted to Chinese EMCO ripoffs). I have even sacrilegiously considered buying an orphan tailstock from a Chinese 9x20 to convert for use. A year or two with this sort of setup and you'll have enough bracketry to deal with any situation (like when milling on the lathe with a vertical slide - use a dial gauge fitted to the cross-slide and a magnetic stop on a bed shear instead of relying on that leadscrew handwheel. I haven't mentioned digital dial gauges as that would defeat my own argument ... Best regards Martin F. Slater (1981 metric Super 7) Matthofstrand 10 6005 Luzern Switzerland ------- Re: Tail Stock DRO Posted by: "Paul Kennedy" clankennedy2004x~xxyahoo.co.uk Date: Tue Nov 6, 2012 3:24 am ((PST)) Very Valid point Martin. I would add however that the streamlined shape of the super 7 tailstock should be a challenge to your ingeniuity and skills as a machinist and not a deterrent! ------- Re: Tail Stock DRO Posted by: "Cliff Coggin" clifford.cogginx~xxvirgin.net Date: Fri Nov 9, 2012 12:55 am ((PST)) > Why all this enthusiasm for frequently inaccurate, expensive, > battery-swallowing cheapo digital verniers? Come now Martin. They can't be both expensive and cheapo. > Why not mount mechanical, no running costs, dial gauges with a 2" or > more range? Why not? Well they are expensive, they are fragile, they are difficult to read, and they only have a tiny range, but apart from that dial gauges are fine. Cliff Coggin Kent UK ------- Re: Tail Stock DRO Posted by: "David Littlewood" davidx~xxdlittlewood.co.uk Date: Fri Nov 9, 2012 4:29 am ((PST)) >> Why all this enthusiasm for frequently inaccurate, expensive, >> battery-swallowing cheapo digital verniers? >Come now Martin. They can't be both expensive and cheapo. I understood that to be a reference to the quality - and that is definitely possible. David Littlewood ------- Re: Tail Stock DRO Posted by: "Haydut1200" haydut1200x~xxgooglemail.com Date: Fri Nov 9, 2012 7:04 am ((PST)) [pedantic mode on] But at 9 quid from Aldi or Lidl, leaving aside the fact that they aren't verniers, they can hardly be called expensive, so basically, they are cheap, cheapo calipers. :) [pedantic mode off] Martin ------- Re: Tail Stock DRO Posted by: "David Littlewood" davidx~xxdlittlewood.co.uk Date: Fri Nov 9, 2012 11:02 am ((PST)) Martin, [cynic mode] I have often found cheap tools turn out to be the most expensive ones of all. [/cynic mode] David Littlewood ------- Re: Tail Stock DRO Posted by: "Haydut1200" haydut1200x~xxgooglemail.com Date: Fri Nov 9, 2012 12:32 pm ((PST)) Touché. :) Martin ------- [posted to Metal_Shapers and also several other groups] possibly OT: Final versions of my Lathe Electronic Edge Finder (can Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Tue Nov 20, 2012 12:43 pm ((PST)) Special Note: this is OT for the Gingery site. Please send any questions or comments off line to me. It took me about a day to perfect the Model 1 Lathe Electronic Edge Finder. It is compatible with machines that have a spindle resistance of greater than 3 ohms. Model 2 performs the same function but handles spindle resistances down to 0.01 ohms. It took me about 6 months of effort working 6 days a week to get it right. So I am very happy and relieved to finally have a design that works. If you have a lathe, then you can read these articles as is. If you have a mill or shaper, then just understand that these circuits detect when the cutter contacts the workpiece. No modification is needed to the cutter or machine. If you are not familiar with machining and want to learn about analog circuit design, then most of these articles apply to you. I have tried to write them for people with a wide range of backgrounds. http://rick.sparber.org/LEEF_Model_1.pdf http://rick.sparber.org/LEEF_Model_2.pdf Component selection and board layouts were masterfully done by Mark Cason. He has generously allowed me to publish his artwork in these articles. He is also planning to have boards made and sell both kits and finished models. I don't know the final prices, but can tell you that the Model 1 cost about $3 in parts and 50 cents for the board. The Model 2 cost about $17 in parts and $3 for the board. At the present time, we are looking for beta testers. If you are interested, please contact me directly. Rick Sparber ------- Date: Tue, 22 Jan 2013 20:50:05 -0600 From: John Holladay Subject: [OldTools] Question for you machinist types. I found a little Starrett 2 1/2" adjustable die makers square recently. I bought it mostly just because I didn't have one and it just kept calling my name. I sure didn't need it. I already have the little 2 1/2" double square (as well as the other sizes too - I kind of have a thing for Starrett). Anyway, since I am not a machinist (Although I have slept in a Holiday Inn Express occasionally), I am curious to find out what the purpose of having a little square like this that can be adjusted (to a small degree) out of square? What purpose would there be to set a square a little bit off from 90 degrees? Obviously, you could not use it like a bevel square or a protractor attachment for a combination square. My little inquiring mind can't grasp what purpose this little square serves. Thanks, Doc Sitting back to wait and absorb the information. ------- Date: Tue, 22 Jan 2013 22:22:29 -0500 From: "Cliff Rohrabacher Esq." Subject: Re: [OldTools] Question for you machinist types. In die making there is a draft on the female part of the tool (the die). A die is made usually with straight sides for about 0.100 to 0.250" (this is to give the die some life for sharpening) thereafter it is relieved by a few degrees to allow for punched out parts to fall away. Such a square is used very much like a bevel gauge checking the uniformity of the relief. ------- How to align work [myfordlathes] Posted by: "garthn444" garthnx~xxpbt.co.za Date: Tue Mar 5, 2013 12:33 pm ((PST)) Hi. I am trying to fly cut a steel bar (to make a rear toolpost) - how do I get the bar aligned at right angles to the chuck (both vertically and horizontally). I guess a clock comes into it... Thanks Garth ------- Re: How to align work Posted by: "David Everett" deverett2003x~xxyahoo.co.uk Date: Tue Mar 5, 2013 3:48 pm ((PST)) You sound like a tyro, so am assuming you don't have too much equipment. Mount up the faceplate. Run the cross slide with the steel bar on it up to the faceplate and butt the steel against the faceplate. That will get it aligned correctly. Take off faceplate and mount chuck. To get the bar on height, use a 'sticky pin'. Simple way to make a temporary one is to get a thin steel bar, say 1/8" diameter and about 4" or so long. Set it in the chuck with about 1/2" sticking out and put an accurate point on the end. Take the pin out of the chuck and attach it to the jaws (anywhere on them) with something like plasticine. Spin up the lathe - not too fast - and using a piece of plastic as a pusher, get the point to run true. Don't be tempted to just hold the pin in the jaws of the chuck because your 3-jaw chuck will not be accurate. Now you can put the point close to the marking out line and you will immediately see how much packing you will need to get the bar up to height. You will probably have to repeat a few times, but when all is to your satisfaction, the bar can be secured to the cross slide with Tee bolts and strap clamps, or whatever you have. This way made seem crude, but you don't need any form of clock and was the way many model engineers did this sort of job years ago before money entered the picture and everyone had all sorts of must-have gadgets. Dave The Emerald Isle ------- Measure Radius of a Curve [SherlineCNC] Posted by: "Thomas D. Dean" tomdeanx~xxspeakeasy.org Date: Sat Aug 10, 2013 1:37 pm ((PDT)) I have a camera mount with a rectangular base. The corners have a radius, maybe 1/2 inch. I want to make a recess for the base so it always fits the same way when I install it. How do I measure the radius of the of the corner? Or, am I better to use a mill that has a noticeably smaller radius and leave a gap at the corners? Tom Dean ------- Re: Measure Radius of a Curve Posted by: "Martin Dobbins" trainnutzx~xxyahoo.com Date: Sat Aug 10, 2013 1:56 pm ((PDT)) Hi Tom, Measure around the circumference of an individual corner, degree of accuracy up to you. Multiply result by 4, then divide by Pi, that will give you diameter so divide by 2 for radius. Martin ------- Re: Measure Radius of a Curve Posted by: "Thomas D. Dean" tomdeanx~xxspeakeasy.org Date: Sat Aug 10, 2013 2:14 pm ((PDT)) With a 1/2 inch radius, measuring around a corner is not very practical for me. I am sort of a klutz. I thought about measuring the base rectangle. Then measure the diagonals. This gives me the including and included rectangles. From this, I can calculate the curve... Getting complicated. I think I will hold drill bits up to the corner and choose the one that fits. Half that is approximately the radius of curvature. Tom Dean ------- Re: Measure Radius of a Curve Posted by: "Stan Stocker" skstockerx~xxcomcast.net Date: Sat Aug 10, 2013 2:20 pm ((PDT)) Ho Tom, There are a couple of ways to get a fairly close measure. Some fairly simple, some convoluted. 1) Trace the mount outline on graph paper. The finer the divisions, the closer a swag you can get. 2) Draw circles of known radius on paper and match up to the base. Iterate to limit of sharp pencil and eyeball or sufficient level of accuracy. 3) Match up endmills to the radiused corners. Or other round bits of shaft to match. 4) Use drafting templates for circles, still available from stationary and office supply stores. Direct compare. 5) Use commercial radius gages. 6) Place a straightedge along one base edge, and a square against the straightedge. Slide the square along the straightedge and up against the adjacent edge. If you do this on white paper with bright or back light, you can probably get a pretty good measurement of the radius directly. This tends to need clamps, tape, a helper, and around seventeen hands with nine fingers each, but it might do the job. You can also use a height gage with a DTI to detect when the edge begins to move away from the height gage. Do it at the top and bottom and you know the length of the straight segment on the given edge to within several thou if you're really careful. Subtract the straight segment length from the overall width, divide by two, and VIOLA!! [SIC] you know the radius. 7) Moving away from knowing the radius and towards redneck engineering, scribe the work to be milled to match the base and carefully nibble away the material to the line. You can hog out most of the waste. I guess you could also use a rotary table and fiddle until the mill traces the scribe mark if you really want a true arc rather than a good approximation. 8) Go high tech and scan the base, edge detect it, import it into a software package with measurement capabilities, and get an answer good to a hundredth or so, but with five digits of resolution and only two significant digits... Groan in despair, mill a big honkin' pocket, coat the base with release compound, and cast the recess with JB Weld :-). Arbitrary precision done home shop style. Have fun, Stan ------- Re: Measure Radius of a Curve Posted by: "Hannah" hannah024x~xxcharter.net Date: Sat Aug 10, 2013 2:22 pm ((PDT)) Tom: Why not make an outside corner radius gauge? Since the corner looks like a 1/2 inch radius I would draw a 1" Dia. circle on a piece of paper. Then fold the paper on the center line of the circle and fold it at 90 degrees to the first fold. Now I would cut out the inside of the circle, unfold the paper and cut the sheet on the fold lines and have 4 outside corner radius gauges. If that gauge doesn't fit the corner of your camera mount perfectly, just draw a larger or smaller circle and make another set of gauges. Or with access to a mill and more time, I would set up on the square corner of a piece of plastic and machine a 1 inch Dia. circular pocket and make a more permanent gauge. That's just the way I would do it. Hannah ------- new article: An Experimental Measurement System [atlas_craftsman] Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Wed Sep 18, 2013 5:29 pm ((PDT)) This article details a digital caliper based measuring system with an accuracy of +/- 0.0005" over a range of 0 to 5.5". Total cost is around $45. If you are interested, please see http://rick.sparber.org/CBOO.pdf Your comments and questions are welcome. All of us are smarter than any one of us. For the full index of my articles, see rick.sparber.org. Rick ------- Date: Tue, 14 Jan 2014 17:27:20 -0800 From: James Thompson Subject: Re: [OldTools] 5th INTERNATIONAL PLUMB BOB COLLECTORS MEETING On 15/01/14 7:07 AM, "Tony Zaffuto" wrote: >> PLUMB BOBS!!!!!! >> I've got well over a hundred (if not more than double that), with no >> duplicates! About 5 or 6 years ago, my wife got the idea to use >> some for decorating one of our Christmas trees (don't ask). Lasted >> just long enough for her to put a dozen or so on one side without >> balancing the other side and over went the tree. On Jan 14, 2014, at 1:24 PM, Mick Dowling wrote: > Yeah, why do they make them so heavy...... I will again tell a story of why plumb bobs are heavy. Because they have to keep tension on the line while a mechanic measures from the string to the object being plumbed (or aligned). I spent most of my Millwright apprenticeship working on the construction of a steel mill in 1956 thru 1959. My introduction to heavy plumb bobs came when we were installing the upright stands for rolling mills. These had precision ground surfaces about 3' wide by 10' tall on the inside edges where the roll bearings would ride. In those days a man who was the factory representative of the machine manufacturer did the supervision and all final inspection of all machinery installations. He was called the "Erector." His word was law. The machine supplier had to warrant the machinery for one full year, and they wanted to be absolutely certain that it was correctly installed. The surfaces of the mill stands had to be plumbed to within .001". To accomplish this we poured about 100 pounds of lead into a can which had a bail, then hung the can suspended into a large bucket of heavy oil from a piece of fine piano wire (what you probably correctly call music wire). This gave us a stable true vertical surface to measure from. To insure that we did not disturb the wire at all while measuring to it we hooked up earphones and a battery to an inside micrometer. One wire was attached to the piano wire which was grounded to the stand. A vertical line was drawn on the machined surface and the inside mic was set against that line at the bottom, then the mic was adjusted until a click was heard in the earphones; static caused by near contact, and thus no actual contact, which would disturb the wire. Then go to the top and repeat. Compare readings, and adjust the stand for plumb. Repeat the process until top and bottom had the same reading on the mic. The adjustment involved loosening the nuts on the 4" diameter anchor bolts, jacking up the stand, adding or subtracting shims, then re-torquing the nuts. Our 6" wrenches were hand burned from 2" thick plate steel, and the tightening and loosening was done with 20 pound hammers while a come-along pulled on the handle. The torque was correct when you could no longer move the nut. Once everything was perfect we could go get the Erector and have him check our work. (So how do you get a jack under a piece of machinery which is sitting on the floor? You don't. You use what is called a "Z-bar." This is a tool which slips a short distance under the edge of the machine, and is the correct height for a jack to go under. Friction holds the Z-bar in place while jacking. These are usually made on the job as needed.) Trust me when I tell you that you did not want the Erector to find that you were being less than honest with him when you told him the piece was correctly installed, nor did you want him to learn that you were incompetent. Either of these things would get you run off the job, and give you a bad reputation as a skilled mechanic. For longitudinal alignment, the surveyors would establish a beginning and an end point as well as a matching elevation point at each end, and we would use a similar setup with heavy weight on a piano wire to establish a working center line. This piano wire was supported at each end by tall batter boards, and was tensioned with heavy weight. A very fine plumb bob was used to align the wire to the end points. Then all machinery was aligned to the piano wire, again using plumb bobs. You may assume from this that I have used a lot of plumb bobs, and you would be correct. I just recently sold my prized plumb bob which was a mercury filled Starrett. The longest continuous machinery setup I ever saw was on this job. It was a hot strip mill, and the machinery was a total of 5/8 of a mile in length, and every single piece of machinery was set to within .001", both in the horizontal plane and in the vertical plane, from beginning to end. I am very proud of having worked on that job, and very happy for the experience. And now, back to your regular programming.... ------- OT, but interesting all the same... [atlas_craftsman] Posted by: "Richard Marchi" rfmarchix~xxaol.com marchirichard Date: Tue May 27, 2014 7:21 pm ((PDT)) So, when I was being taught the trade in the early 60's, the old guys showed me how to transfer measurements using simple Starrett or B&S inside and outside calipers. I was taught to "feel" a measurement and then use an inside or outside micrometer to get the actual dimension. If I recall, if you were really good at it with a nice light touch, you could get better than a thou. So now, 50 years later, I am trying to fit a 5 C collet closer to a 6" faceplate. The problem is that the bore on the collet closer is about 3.770" diameter, but only 0.217 deep. I'm cutting the faceplate with a corresponding diameter boss that is 0.200 deep. I have a 3"- 4" inside and outside micrometers reading in tenths. Neither micrometer will measure these diameters, because their anvils/ measurement shafts are too thick. I could use a digital caliper, but it doesn't have the precision to get a really good fit. So.. It seems that I'm back to the old timey simple calipers. I didn't own a set, but just bought some on eBay today. Who would have thought that the old timey tool was what was needed. Now if I can only remember the "feel". Dick Richard Marchi 600 Water Street, SW NBU8-2 Gangplank Marina Slip H-22 Washington, DC 20024 ------- Regarding inside and outside calipers. Posted by: "Steve w" stevewatrx~xxhotmail.com Date: Wed May 28, 2014 7:43 am ((PDT)) There is a section on taking measurements in the old South Bend book "How to run a lathe" that covers calipers, and transferring measurements. This book is still in print, and if you do not have one, I highly recommend it. Steve W. ------- Re: Regarding inside and outside calipers. Posted by: "L. Garlinghouse" lhghousex~xxsuddenlink.net Date: Thu May 29, 2014 8:24 am ((PDT)) I've found the old-school 2 legged spring loaded calibers useful as well. Right now I am using a boring head on my vert. mill. There is minimal clearance between the withdrawn cutting tool and the internal dia. being opened up. Regular 4-way calipers [aka "dial" if they have a dial, "DRO" or "Digital" if the have a digital display, or "vernier" if they have a vernier scale on them] simply will not work because there is not room enough to get them vertical to get a good reading. So my old [maybe belonged to my great-grand father, certainly my Dad] 2-legged inside calipers do the job followed by reading their opening with my dial 4-way calipers. When I get close to the final cut I might use my telescoping T gages, but for quick and good, the old school ones are just fine. Note for Newbies: What are the 4 ways of the modern caliper? 1. OD measurements with the inside surfaces of the big jaws 2. ID measurements with the pointy knife edged jaws oppposite of the main jaws 3. Depth measurements with the tail that sticks out of the right end as you open the jaws 4. and finally step measurements using the step that forms off of the other end as you open the jaws. Some calipers only are set up for the first 3 modes. Often the inner part [the part closest to the "beam" on the insides part of the main jaws have a knife edge on them for measuring grooves. Maybe I should have called this 1.1? [Nyaaahh!!] Most of this on the chance that someone hadn't really appreciated the original thread or was missing all the different flavors of calipers. L8r, L.H. in the Rainy, Wet [but still pleasant] Ozarks ------- NOTE TO FILE: The following is one tiny bit of practical information that came out of a long discussion in the sherline group about choosing either a metric or imperial lathe, that transformed into a history of measurement systems and beer containers ;-) ------- [sherline] Re: Simple metric conversion - was: Lathe: Short or long, risers or Posted by: "Ian Newman" ian_newx~xxyahoo.com ian_new Date: Sun Jun 1, 2014 2:02 am ((PDT)) Hi Dave, There is a very quick and simple way to convert from aliquot inch measurements to millimetres: Take the inch fraction and repeatedly multiply the top and bottom by two until the denominator equals 256. Make the approximation of 25.6mm to the inch - shifting the decimal point of the numerator one place to the left gives you the dimension in millimetres accurate to better than 1% Example: 1/8 inch = 2/16 4/32 8/64 16/128 32/256 = 3.2mm (actual value 3.175mm, 0.79% error) As the error is just under 1%, a better approximation can be quickly calculated by taking the original estimate, moving the point two places to the left (giving 1% of the estimate) use only the most significant digit and subtracting this correction from the original estimate: 1% of 3.2 = 0.032 take only the first digit = 0.03 3.2 - 0.03 = 3.17 (-0.16% error) Another example: 9/32 inch (real conversion = 7.144mm) 18/64 36/128 72/256 = 7.2mm (first approximation, error =+0.79%) =7.2-0.07 = 7.13mm (second approximation, error =-0.19%) Even I can manage to multiply by two and divide by ten in my head.... All the best, Ian ------- Looking for odd-ball caliper [atlas_craftsman] Posted by: wa5cabx~xxcs.com wa5cab Date: Sat Aug 9, 2014 8:34 pm ((PDT)) Every now and again, I need to measure the distance between two small holes. For that, I once found a pair of caliper jaw attachments that convert the jaws to conical points which, so long as the holes are approximately the same diameter gives you a pretty good answer. But if measuring the distance between two pins, you are stuck with measuring either outside to outside or inside to inside and subtracting or adding the mean diameter of the two pins. Has anyone ever seen a pair of calipers with both jaws "looking" the same way so that you could directly measure the distance between two pins of the same diameter? Robert Downs - Houston wa5cab dot com (Web Store) MVPA 9480 ------- Re: Looking for odd-ball caliper Posted by: "Scott Henion" shenionx~xxshdesigns.org shdesigns2003 Date: Sat Aug 9, 2014 8:49 pm ((PDT)) How about using a depth gauge? Scott G. Henion, Stone Mountain, GA Craftsman 12x36 lathe: http://shdesigns.org/Craftsman12x36 Welding pages and homemade welder: http://shdesigns.org/Welding ------- Re: Looking for odd-ball caliper Posted by: wa5cabx~xxcs.com wa5cab Date: Sat Aug 9, 2014 9:16 pm ((PDT)) Scott, I thought about that, but accuracy wouldn't be too good as the depth gauge rod would have to be at a slight angle to a line through the centers of the two pins. Plus a micrometer depth gauge will typically have a base about twice as thick as the rod, so the rod wouldn't be in a plane perpendicular to the axes of the two pins if the pin lengths were very short. Error would decrease as the distance between the pins increased. Robert Downs - Houston ------- Re: Looking for odd-ball caliper Posted by: "David Beierl" dbeierlx~xxattglobal.net dgbeierl Date: Sat Aug 9, 2014 9:33 pm ((PDT)) If the holes are the same diameter you can measure one with the inside jaws and zero the (electronic) caliper. Then measure end-to-end with the inside jaws and the reading will be the center distance. Yours, David Beierl ------- Re: Looking for odd-ball caliper Posted by: "Carvel Webb" carvelwx~xxabsamail.co.za cwlathes Date: Sun Aug 10, 2014 12:44 am ((PDT)) Hi Robert, See Mitutoyo approach: https://groups.yahoo.com/neo/groups/atlas_craftsman/attachments/906336897 A colleague of mine also used an inside jaws micrometer for the purpose by subtracting the width of the one jaw from the total and using the back edge, which even though not ground was accurate enough. Regards, Carvel ------- Re: Looking for odd-ball caliper Posted by: "Charles" xlch58x~xxswbell.net Date: Sun Aug 10, 2014 9:12 am ((PDT)) Measure from outside to outside, then measure from inside to inside. Divide the difference in half and add it to the inside measurement. ------- Re: Looking for odd-ball caliper Posted by: djkvx~xxatt.net cageycretinx~xxsbcglobal.net Date: Sun Aug 17, 2014 11:52 pm ((PDT)) Not that it's difficult but why do all the math? This is how I do it. When the pins are the same diameter it's not necessary to calculate. Simply measure (with the depth gauge of your caliper) from the inside of one pin to the outside of the other. That gives you the centerline distance between the pins without all the calculation. However with pins of different diameters some calculation is required. But It is fewer steps (thus less chance for error) to simply subtract the radius difference from the measured result. Example: a 0.500" pin and a 0.750" pin the radius difference is 0.125" (1/2 of the diameter difference of 0.250"). If the pin distance is 1.125" (or 1-1/8") as measured above, then the centerline is 1.000" (1.125" minus 0.125"). Another example: with a 1.00" pin and a 2.500" pin the radius difference is 0.750" (1/2 of the 1.500" diameter difference). If the distance as measured above is 7.6250" (or 7-5/8") then the centerline is 6.875" (or 6-7/8"). The above method works real well on pins and in theory works the same with holes too. However due to a basic calipers design for close tolerances the inside to inside and outside to outside method will give the best results when measuring holes. That's my little madness to the method. Cheers ------- Re: Looking for odd-ball caliper Posted by: djkvx~xxatt.net cageycretinx~xxsbcglobal.net Date: Mon Aug 18, 2014 12:25 am ((PDT)) P.S. Just saw my method mentioned above. You have to measure at the ends of the pins and not the diameters to get your most accurate measurement with the calipers depth gauge. Measuring with the depth gauge from the diameter most times is impossible especially with larger diameter pins. And yes, as previously explained the depth gauge method is also not real accurate to measure on the pin sides since it is not a true straight line but rather a triangle. Measuring from the top of the pins should be real close unless the pins are bent. But then if the pins are bent then no method will be accurate. ------- Re: Looking for odd-ball caliper Posted by: stephen_s_woodx~xxyahoo.com Date: Mon Aug 18, 2014 8:35 am ((PDT)) If you have measured so that the diameter of the the larger pin is included and the diameter of the smaller is excluded, then you are correct to subtract half of the difference in diameters, ...BUT... if the diameter of the smaller pin is included and the diameter of the larger is excluded, then you would add half the difference. Simpler is the method proposed earlier: use half the sum of the meaurement taken including both pins and the measurement taken excluding both pins. ------- Re: Looking for odd-ball caliper Posted by: "Charles" xlch58x~xxswbell.net Date: Mon Aug 18, 2014 9:13 am ((PDT)) If the pins are the same size and you are using a digital unit then it is easy to measure one pin, zero the caliper and then measure across the pins. This will give you the center to center distance. In general though, keep a pad of paper and a pencil as well as a calculator if you must in the shop. I keep mine on an old secretary copy holder over the lathe, along with drawings of whatever I am working on. If you aren't comfortable with doing math, machining is not for you. Charles ------- NOTE TO FILE: And if you are challenged when it comes to visualizing things clearly in your mind's eye, by all means draw it out on paper. My mind's eye is virtually blind, only capable of visualizing something for a tiny fraction of a second before it fades. For more than forty years I always thought that references to "mind's eye" visualization in detail was a fiction until I searched the internet and found that humans run the full range from: -- some being truly capable of visualizing in minute detail, and modifying and rotating the mental image or sketch at will; -- to a sizeable portion that are like me and visualize next to nothing but think in terms of facts and descriptive words. So those of us with a visualization problem do just fine making paper sketches and plans. ------- Starrett last word - what to buy [sherline] Posted by: zerodbx~xxbellsouth.net Date: Sat Jan 10, 2015 5:32 pm ((PST)) Buying the Starrett last word is on my list to do. However, just like anything else, I am overwhelmed by the different attachments, kits, etc. I have no idea what to get that will cover the basics of my 5400 Mill and Lathe. I just want to make sure I am buying the right attachments that the DTI will attach to. I am quite ignorant, so any item numbers - specific part numbers would be great. Another question is that it seems that I should be locking down the rotation of the mill spindle while such measurements are being made. If so, then how do I do this? Thanks Donnie ------- Re: Starrett last word - what to buy Posted by: "Ken Condal" kencondalx~xxyahoo.com kencondal Date: Sat Jan 10, 2015 5:51 pm ((PST)) Like you, I dreamed about a Starrett Last Word with all the accessories. When I got it I hated it! It sits in a drawer and never gets used anymore. I later bought an Interapid and I love it. It’s easier to read, auto-reverses and it has dovetails so it mounts to anyone’s accessories. http://www.longislandindicator.com/p23.html Yes, you do have to lock the spindle to use an indicator. I made one for my customized spindle, but I’m sure there are others here who can show you how to do it with a standard Sherline spindle. Ken ------- Re: Starrett last word - what to buy Posted by: "Ian 1" ian_newx~xxyahoo.com ian_new Date: Sun Jan 11, 2015 5:28 am ((PST)) Hi Donnie, I would recommend you find out what you need by experience: Buy a second hand device on eBay or similar and learn what suits your needs (we all have different requirements). I would suggest a couple of points: Get a DI rather than a DTI - it can do everything the DTI does, but it will also allow you to make absolute measurements over a greatly extended operating range (rather than being limited to comparative indications). Give serious consideration to the level of precision you really need -- an indicator that measures in "tenths" may give you "bragging rights" but is probably best avoided unless you need to work to such limits as they are prone to "stickiness" which leads to inconsistent readings. All the best, Ian ------- Re: Starrett last word - what to buy Posted by: zerodbx~xxbellsouth.net Date: Sun Jan 11, 2015 6:35 am ((PST)) The reason that I mention 'the last word' is that back in time that is all I ever heard out of folks about this device, so naturally now, I assume that this is still the case (of which now I see that this is not necessarily the case anymore as one pointed out about the interapid). Trying out different 'things' has always proven frustrating to me. I simply do not have the time nor resources to try by experimentation. I already bought a device from LMS (not knowing any better about the DTI's) and I wound up with a device that I am not sure if it is the unit that is not good or it is the "user" aka 'me'. I think the unit was around $30 or $40 or so. Seems like the dial is awful jumpy. Doesn't matter -- I have tried using it attached to a magnetic base to read Lathe Spindle runout. Never -- never could get the thing to "settle down" and do right. Side note: At my job many years ago, I used to work on commercial broadcast video tape recorders. These VTRs were about $50,000 each and I used a DTI at least once each two months as I had to change -- replace the video head assembly. The DTI had a very sturdy bracket attachment assembly that all of this installed to a prefabricated "threaded nub" on the chassis of the VTR. I can't remember the specs, but I can tell you that I could check the "eccentricity" or the run out of the Video Head and that DTI was "smooth as glass". I would always find the "highest" reading and then tap on that side to recenter the Video Head" then reset my DTI. I could get the reading down and watch the dial as it would "fluctuate" to what I thought was an incredible amount of control and accuracy. It is unfortunate that I cannot remember the tolerance. But, I can tell you that I do have "professional" experience with working with pro equipment. Now, that I am trying to "read" my lathe or vise "travel offset", I cannot seem to enjoy the same type of "response" of a smooth action. My present DTI just jumps around so much, it literally, jumps and does not provide a smooth up and down readings. There is no way I can any high and low point with it. So, now that I have been down this road, I do not have the time, trial and error to continue on this road. I don't mean to sound difficult as I am not this kind of person. I am just ready for someone out there to say -- buy this and do this. Just like it finally dawned on me that I had to figure a way to lock down my spindle as it seems the spindle was being turned ever so slightly by the "friction" of the DTI "tip" riding up and down. Thanks to all for your kind help ! Donnie ------- Re: Starrett last word - what to buy Posted by: zerodbx~xxbellsouth.net Date: Sun Jan 11, 2015 6:54 am ((PST)) Oops, I meant interapid. Also, what attachment should I use as the interapid does not come with any attaching device to the Mill Spindle. It only has that 2mm Dia Hardened Steel Insert. This is what I found as far as interapid goes: Dial Test Indicator, Indicator Style Horizontal Range 0 to 0.060 In. Graduations 0.0005 In. Dial Reading 0-15-0, Dial Size 1-1/2 In. Dial Color White, Series Intrepid 312, Range per Revolution 0.0600 In., Bearing Type Jeweled, Reading Balanced, Contact Point Dia. 0.080 In., Contact Point Length 3/4 In., Contact Point Style Hard Steel or Tungsten Carbide, Features For Measurement at 12 Degrees, Revolution Counter, Constant Measuring Rotation, Jeweled Movement with Rubies ------- Re: Starrett last word - what to buy Posted by: "Ken Condal" kencondalx~xxyahoo.com kencondal Date: Sun Jan 11, 2015 7:17 am ((PST)) There is a 3/8” adaptor that slips over the stem and allows the indicator to attach to the mill. Most places that sell the indicator offer the adapter. Ken ------- Re: Starrett last word - what to buy Posted by: "Flosi Guðmundsson" flosigudx~xxtalnet.is flosi2001 Date: Sun Jan 11, 2015 7:29 am ((PST)) Hi, Here is a link to a comparison of dti's by Long Island Indicator Service Inc: http://www.longislandindicator.com/p14.html They are rather pessimistic about almost all dti's other than swiss made, Compac, Tesa, Interapid. I have two Brown and Sharp made by Tesa and like it and also several Gem's which is a Last Word look-a-like. The swiss made B&S is better made but the other works too. I bought all these DTI's used at eBay. Some of the Gems were full of grime and nonworking, but cleaning fixed that. I have a book: "Repair of Mechanical Dial Indicators and Calipers", by Michael Yamamoto that has exploded views and servicing tips that helped me get them working. Buying used might be worth a consideration. regards, Flosi ------- Re: Starrett last word - what to buy Posted by: pappy50x~xxcox.net papahoteljuliet Date: Sun Jan 11, 2015 9:01 am ((PST)) Ok, I'm going to let the cat out of the bag on Starrett. I like buying broken Starrett tools. Why? Because you can get them really cheap. I bought my Last Word DTI for $40 at my local machinist reseller and it was broken but came with a good case and most of the accessories. What most people don't seem to know is that Starrett has a repair facility that is really reasonable. As I recall it cost me about $60 for them to completely refurbish the tool and bring it back to factory specs. So for about $100 I have a like new (and certified accurate) DTI. Did the same thing with a micrometer and dial calipers. I think I have less than $350 in all three tools and that is a heck of a lot less than new ones and they will last me a lifetime. Being a U.S. company they offer great service for customers even if I have never purchased a brand new tool from them. The only down side is it takes four to six weeks to get the tool back. If you can wait, you can get a great bargain. ------- Re: Starrett last word - what to buy Posted by: "Gerald Feldman" gfeldman2904x~xxpacbell.net rsojerry Date: Sun Jan 11, 2015 12:02 pm ((PST)) If one decides to go this route, it is prudent to check in advance that the instrument you purchase is one that Starrett still services. They do not always have parts for some of their older or discontinued instruments. Otherwise, this can be a way of getting an excellent instrument at a “discounted” price. Jerry F. ------- Re: Starrett last word - what to buy Posted by: chieftoolmakerx~xxearthlink.net glicker31 Date: Sun Jan 11, 2015 8:30 pm ((PST)) Hi Donnie, sorry for the delay, but you know my situation. My very first DTI was/is a L.S. Starrett Last Word. 711-F Two things I did/do not like. The reversing lever, which tends to stick sometimes. On the body, near the contact point, there is an opening which allows chips, and debris to enter the indicator and cause havoc. Finally, after many years, Starrett addressed the problem, and one can buy a dedicated rubber "boot" to seal the gap. Now, to be more positive, and simple. Your choice will be governed by your application, and your budget. I have many indicators. For different purposes. DI's DTI's My favorite is Interapid. I also have Brown and Sharpe, Federal, Compac, etc. You can go to Long Island Indicator and get the real scoop/skinny about all the best indicators. Since you have a mill and lathe, you can make your own attachments. I have no commercial connection with any firm I might mention. Just a satisfied owner/user. Regards, Jerry G (Glickstein) (I am open 24/7 for any questions...... :) ------- Re: Starrett last word - what to buy Posted by: "Tom & Judy Bank" trbank1x~xxverizon.net eimcr28 Date: Mon Jan 12, 2015 4:43 pm ((PST)) Donnie, When buying an indicator, especially a DTI, be careful that you don't get one with too small a ball on the tip. The smaller the ball, the more it will jump in and out of any irregularities in what you are checking. If you have a piece like a dowel pin with a mirror finish, that is likely not a problem; but if you have a piece that has been nicked, dropped, or stashed with other raw stock, you can expect a DTI tip that is less than 1/8" to make like Fred Astaire, especially if the DTI reads in 0.0001" increments or less. Regards, Tom Bank ------- Re: Starrett last word - what to buy Posted by: "JB" jambomacx~xxsbcglobal.net jamboacn Date: Mon Jan 12, 2015 6:47 pm ((PST)) Donnie, Lot of good info in this thread. The "buy cheap Starrett, get it fixed" advice is excellent. I’d also recommend buying a cheapo and a midrange to check against and use when you don’t need high precision on dinged up parts. I have found some of the "cheap" DTI’s to be just as accurate as my Starrett. When I need exacting measures, I’ll rough with the cheapo and finish with the Starrett… then check again with the cheapo to be sure the cheapo is still just as good. For less than the cost of a brand new Starrett, you can have a few DTI’s that will meet varying needs and allow you to not "over use" your Starrett. HTH, John B. P.S.: Always hated when the rookies blasted my DTI’s to uselessness when they’d let them wander down to the heads on the drums... spent more on test equipment than on the vtr refurbs some months! ------- Re: Starrett last word - what to buy Posted by: "Forrest A" atkinonx~xxhotmail.com atkin_on Date: Tue Jan 13, 2015 6:00 am ((PST)) You can buy Starrett Last Words at Model engineering shows, used for as little as $35. I would try to find several ball sizes. The small ball end tips work great for indicating narrow surfaces and also small holes. The most versatile mount is the ball and socket with a nice length rod. That setup allows for mounting in the tail stock chuck and indicating parts in the ind. 4 jaw. ------- Mounting scales on Micro Lathe II [TAIGTOOLS] Posted by: rogerpjrx~xxmsn.com rogerpjr Date: Tue May 19, 2015 9:38 am ((PDT)) I was thinking about putting a small DRO on my Taig lathe. I figured I would need a 6" for the cross slide and a 12" for the carriage. I was thinking of putting the carriage one on the back side but there isn't much room for the cross slide. Can anyone tell me the best way to mount these? Also, I'm on a pretty limited fixed income without much room for goodies, does anyone have good sources for low priced scales? ------- Re: Mounting scales on Micro Lathe II Posted by: gfbx~xxmypage.net wildhorsesoftware Date: Wed May 20, 2015 7:50 am ((PDT)) IMHO the iGaging type of scales are the best buy, especially in the longer sizes. Pick a size that is exactly the size you need, or buy longer ones and cut them down to size. Don't buy shorter than the travel of your machine or you will limit your travel to the travel of the scale. Another advantage of the iGaging style is the fact they operate on 3vdc instead of 1.5vdc (like the generic "Chinese" scales). The higher voltage gives them a little bit more noise immunity, which can be an issue in high (electrical) noise environments such as our machinery. Amazon seems to have a good selection of iGaging style scales at reasonable prices. ------- ------------------------------------------------------------------ This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------