Milling tips here are generic for the most part. If the conversation is about a specific brand of mill, it is likely that you can adapt the procedure or tip to your particular model and needs. There are many situations where a SHAPER may be a viable alternative to a MILL. Certainly the ability to easily create and sharpen bits at home for the shaper, whereas mill cutters are always expensive to buy, is something to consider. (A whole shaper can be bought for the price of a handful of larger mill cutters.) But one case, a blind ended T-slot, is probably better handled by a mill cutter. There is a conversation to this effect in the Shaping Tips file. See messages there starting: 27 Jan 2004 From: n8as1x~xxaol.com Subject: Re: Re: what's going on in your shop? Why not read all the shaper files? Can't hurt to learn something new :-) 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 more than 70 additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/ 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. Working with metals and machinery and chemicals and electrical equipment is inherently dangerous. Wear safety devices and clothing as appropriate. Remove watches, rings, and jewellery -- and secure or remove loose clothing -- before operating any machine. Read, understand and follow the latest operating procedures and safety instructions provided by the manufacturer of your machine or tool or product. If you do not have those most recent official instructions, acquire a copy through the manufacturer before operating or using their product. Where the company no longer exists, use the appropriate news or user group to locate an official copy. Be careful -- original instructions may not meet current safety standards. Updated safety information and operating instructions may also be available through a local club, a local professional in the trade, a local business, or an appropriate government agency. In every case, use your common sense before beginning or taking the next step; and do not proceed if you have any questions or doubts about any procedure, or the safety of any procedure. Follow all laws and codes, and employ certified or licenced professionals as required by those laws or codes. Hazardous tasks beyond your competence or expertise should also be contracted to professionals. Let's be really careful out there. (c) Copyright 2003 - 2008 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: Gregory Gagarin Date: Sun Jan 2, 2000 9:22pm Subject: Re: Sherline Mill Tramming/Tooling Plate Yury, I use a Sherline 5400 mill which is now 1 1/2 years old and get very good high precision (0.001" or better)results. I do have 2-3 thousands spongyness in the column/headstock relative to the table, as you described, but this rarely causes problems if you make sensible cuts and finish with a light cut and a sharp tool at high RPM (don't lean on the column or motor while moving the Z-axis handwheel). I think this is normal (you have a lot of leverage there on relatively small structures) but it returns to a stable alignment and I've never seen mine "knocked" out of alignment in normal use. The bigger concern is the Z axis stick and release tendancy which has been addressed many times in this group (see previous posts). In reading your post, I see several possible sources of error: 1. Cheap surface plate -- not a player. Cheap angle plate -- probably not a problem as you can shim to square. Cheap square -- big problem. Your square is your primary reference in setting up the mill for which I am aware of no work-around. Woodworking squares are totally useless and good machine shop squares are expensive. I use the relatively "inexpensive" Mitutoyo grade B (made in England) squares -- I have 3 different sizes which is convienient. They are not the best but are within about 0.0006" of square end-to-end. This is a good place to spend your money and something to take good care of. I assume you have a good working procedure for squaring the mill that ends in a spindle sweep of a flat table surface. For my mill, the table surface is not flat on the X-Y plane -- it is 0.0015" low at the back (x-axis) edge -- so I have to shim my square for all subsequent alignment steps and put a 0.0015 shim under the back edge of all setups on the mill table. 2. I find the use of a Dial Indicator (DI) very awkward for squaring the mill. I have a B&S DI(0.001") which I rarely use. I have 2 Dial TEST Indicators (DTI) (B&S Bestest and Mitutoyo #513-112 -- both 0.0005") which I use all of the time. The "touch" of a DTI is very light compared to a DI. I can set my square on the mill table and sweep the edge of the square with a DTI in the spindle without moving the free-standing square. I particularly like the Mitutoyo DTI since it is a "barrel" type with a .375" stem which can be held in the .375" end mill holder on the spindle and, with its 1.5" long tip, can sweep almost a 3" diameter circle without other holding attachments. This is particularly useful for checking square prior to flycutting as it covers approximately the same area. 3. Machining large flat surfaces with multiple setups is fraught with difficulty -- this is where large mills and surface grinders reign supreme. Insure that you use the same reference surfaces for all setups -- this may require an externally held DTI setup (such as a magnetic base indicator holder) in order to reach the reference surfaces when you move the stock for subsequent cuts. An alternative to simplify your task may be to machine two or three smaller pads for the finished plate to rest on vice the whole surface -- this is how the head attaches to the lathe bed and mill saddle (note that the center protion of the surfaces is milled out to limit contact to the outer surfaces simplifying the milling). 4. Metals warp. When you machine away surfaces on, or drill/bore large holes in, metal plates you may relieve internal stresses resulting in warpage -- this can be significant and varies with metal type, forming process and heat treatment. I always try to reserve my finishing cuts on precision critical surfaces until the bulk of metal removal is complete and the stock has been allowed a day or so to "cure". There are others in this group who can tell you a lot more about this -- I'm certainly no expert. 5. Fly cutting. You will normally get a slight cut on the back side of the circle due to flexing during a heavy cut but this should almost disappear in very light finishing cuts -- leaves a nice flat irridescent surface of crisscrossing circles. The back cut should never completely disappear since it is cutting across the "grain" of the leading cuts where there are always ridges in the cuts that should be in contact if your equipment is square. You can see the intersecting edges between cuts but should not be able to feel them on the surface with your fingernail -- a DTI sweep across these edges should show less than 0.0005". It sounds like you may not have the mill spindle square and perpendicular to the surface -- check it with a large DTI circular spindle sweep. Also, make sure your spindle and flycutter MT1 surfaces are clean and that the flycutter is properly seated. Lock the Z-axis firmly prior to each cut initiation. Hope you find this helpful -- don't scrap your mill yet as it should serve you well within the limits of its design. Greg ------- From: Gregory Gagarin Date: Tue Jan 4, 2000 2:15pm Subject: Re: Sherline Mill Tramming/Tooling Plate Yury, when I said that my table was low on the back side by 0.0015", what I meant was that the entire "table assembly" (everything above the X-Y plane of motion) was "thiner" at the back than at the front. The table plane is not parallel to the X-Y plane. I measured this by fixing a DTI "in space" above the table (attached to the column, head, or even an external mounting) with the tip resting on the table measuring in the Z direction. You then move the table in X and Y under the DTI tip -- the Z reading should stay the same -- the inclination of the X-Y plane makes no difference and thus this has nothing to do with column alignment. Mine remained virtually the same for all X but varied by 0.0015 in Y (higher at the front of the table than the back) for all locations (X) on the table. You CANNOT correct this condition by shimming the column -- you want the column (Z motion axis) perpendicular to the X-Y motion plane not perpendicular to the table if it happens to be a slight wedge like mine. The only way (I know) to proceed from here (without modifying the table) is to place a shim (0.0015) on the back edge of the table and rest the base of your square across the shim and the front edge of the table (the top surface of the base of the square will now pass the above test in Y and the vertical edge of the square is a good reference for alignment of the column axis in the front-to-back Z-Y plane). If the Y axis of your table is good, remove the shim when you rotate the square 90 degrees to align the column axis in the Z-X plane. You complete the alignment this way and when you finally sweep the table from the spindle you will see that it is 0.0015" lower on the back side. Everything you mount on the table will now need to be shimmed on the back to compensate for this KNOWN error in the table but your mill will be square. An alternative to the above is to "modify the table" by covering it with a mill plate. Here you check the top surface of the mill plate (as in the first step above) and shim it as necessary until it is "level". This then becomes your new table and is used for all subsequent alignment with no need for further correction. The disadvantages in this approach are that you need a near perfectly flat mill plate with good attachment points, you shorten the Z axis and you give up the subsequent use of the T-slots. In the alignments of my equipment, I find it helpful to frequently remind myself that I am aligning motion axes -- not surfaces. The surfaces are shimmed as necessary to get the X,Y & Z axes mutually perpendicular and to align the spindle axis relative to these axes (normally parallel to the z axis). All of these measurements ar dynamic ("sweeping") measurements (not simply placing a square between mill surfaces as used for rough alignment). On the Sherline there are no provisions for varying the alignment of X to Y and the table is assumed to lie in the X-Y plane (hense the above problem). ------- From: Ross Heitt Date: Tue Feb 22, 2000 12:42pm Subject: Flat Bottom Holes When a flat bottom is required I always drill the depth with an ordinary drill and then finish the bottom with another bit with the tip ground off flat. This is easy to do and works fine for me. :) Ross ------- From: tim deagan Date: Thu May 4, 2000 9:59am Subject: Re: Stiff X axis on mill (new clue) In sherlinex~xxegroups.com, "tim deagan" wrote: > Hello you helpful people ;-) > I was making my own t-bolts out of 1/4" machine screws (the kind with > the low dome head on top of the 4 square sides) by machining the head > flat and machining two sides down to the proper width. I was taking > pretty light cuts (.003") with the bolt held in the vise (by the lip > of the head so that the 'square' edge at the top of the screw was on > the top edge of the vise jaws. > Everything was going fine for 10 or 15 cuts when all of a sudden.. ! > WHAM! ..the mill grabs hard on the screw edge. The screw jumps out > of the vise, the vise shifts out of true, the entire mill jumps hard. > I turn the power off. I stand back. Impressed. Grateful the > spinning edge mill jumped _away_ from me. > > I assess the damage. Seemingly nothing is harmed. An ugly cut on > the screw, but that's a small price. I use a Starret Last Word to > indicate in the X-axis travel and it's as good as the day I bought > it. However, I notice that the X-axis wheel is very stiff while > moving the x-axis right to left. Not stiff at all moving left to > right. Only stiff on about the middle third of the right to left > travel. I clean, I lube. No change. > Last night I got brave and decided to tear down the X-axis to see > what I can see (hey, I bought the thing to learn :-) I clean out the > lead screw and nut, I fix up the backlash adjustment. I clean, I > lube. I put it all back together. I did not determine how to do > much of anything to the saddle nut. > The stiffness is better, but not gone. Still present only in one > direction of travel for a small section. Any ideas? Thanks, --Tim All, I spent a good deal of time last night with my dial indicators trying to determine if I had wonked up the travel, luckily I can't seem to find any problems. I tried a couple of different setups with my vise and rotation (not rotary) table. Then I started indicating with nothing setup on the table. The stiffness almost completely went away. Apparently the clamps on the vise or the t-nuts on the rotation table are causing the stiffness. I had thought I was being careful not to overtighten, but perhaps I am bearing down too much. Anything less than what I have been doing barely seems adequate to keep parts in place during milling. Not that I have a torque hex wrench, but any ideas about what appropriate torque would be? I could set up a standard torque wrench setup and practice till I have the feel down. I suspect that climb milling may well be the source of my grief. I get a little confused on figuring out whether I'm doing climb or conventional milling when face milling (in my ignorance it seems like I must be doing both.) It's much easier to determine when edge milling. As a novice with no access to anyone with any experience (best I can do around here is find someone who can kinda recognize a drill press 'cause their Dad had one :-( I am incredibly grateful for this forum and the help I have received. Tim ------- From: Marcus & Eva Date: Thu May 4, 2000 1:21pm Subject: Re: Re: Stiff X axis on mill (new clue) Something is not right! You should be able to snug a flat part or a flat vise down pretty good on the Sherline table. The stiff spot may be a hump in the table; check it for flatness with a straight rule and blueing, or on a surface plate. Check the leadscrew by rotating it in a vee block with an indicator. Check the vise for flatness with a rule and blueing as you did with the table. ------- From: Marcus & Eva Date: Fri May 5, 2000 11:31pm Subject: Re: Thanks for suggestions(Drilling small holes in cop per clad board) Don't do it Dave. Get yourself a couple of circuit board drills; they are solid carbide with a 1/8" dia shank and can be held easily in a 1/8 collet. Run them as fast as the mill will go. They cost about $10.00 CDN apiece from KBC (at least that was their price last time I bought some.) They are stiffer than High speed drills. If you still have a wandering problem, make up a spotting point from a 1/8 bit of high speed steel. Grind on 3 flats at 120 degrees to get a triangular point. Make the included angle about 60 degrees. To get the point dead nuts in the center, whip the lathe headstock off the lathe and mount it on the mill table at a 30 degree angle. Get a mounted grinding point (Dremel is ok) and chuck it in the mill spindle. Rough out the point freehand on the bench grinder, and then chuck it in the lathe headstock. You can eyeball the 120 degree increment using the chuck jaws; you don't care about the accuracy of this indexing anyway. All you want is the point in the center. Touch up the point with the grinding wheel , and you're in business. Good luck Dave Marcus. ------- From: "Rich D." Date: Thu Jul 27, 2000 7:16 pm Subject: Re: [sherline] End mill instead of fly cutter? > Hello, I'm new to the group and to machining. I did not buy the fly > cutter and now need to square a piece of steel. Is it OK to use an end > mill? Would the surface look as good as if it was done with a fly > cutter? Thanks! Rogerio Rogerio, Endmills will do fine. If you use the 'end' rather than the side, try to use one that is bigger in diameter than the stock. The results will be the same assuming the edges are sharp.Be safe. Rich D. ------- From: "Flosi Gudmundsson" Date: Thu Jul 27, 2000 7:39 pm Subject: Re: End mill instead of fly cutter? >>From: "Keith Yundt" Date: Fri Jan 21, 2000 1:04 pm Subject: [sherline] Tool making tip Happy New Year! I thought I would share an idea I had while making myself a flycutter for my lathe: Rather than have to make a #1 morse taper, I use the #1 morse taper adaptor that came with my 3/8" drill chuck. That way I didn't need to make the taper, and I already had the drawbar too. So I made the flycutter (which looks like the Sherline version holding a 1/4" bit) and thread the morse taper adaptor into it. The best part about it was that once the flycutter part was drilled and tapped, the piece could be threaded onto the adaptor and put in the lathe, making sure it would turn out true and also made it easy to machine. A future benefit is that I can make other pieces to thread onto the adaptor in a similar way such as a gear cutter arbor, end mill holder etc. Anyway, you get the idea, hope it helps someone! Keith. << You can easily make your own flycutter as Keith Yundt described in Sherline message no. 995. I did and it works great. I also made a circular saw arbour. One of the grat things about lathe and mill is that they can be used to make other tools. Flosi ------- From: "Rich D." Date: Thu Jul 27, 2000 7:43 pm Subject: Re: [sherline] Re: End mill instead of fly cutter? Rogerio, "try it any way". Yes. Draw file it if you want a better finish. OK,OK! WHAT'S A DRAWFILE! Hold a flat file in both hands like it was a stick with both thumbs pointing together, sorta. Pull or push the flat file surface (file at right angles to the work) against the work. Use oil for best finish. Harder to describe than do. Gives a straight brush finish depending on the file's finish grade. Always use a single cut file, smooth or smooth bastard. Alternatively, tape a sheet of 'emery' paper to a hard, flat surface and stroke the metal on that. Back to my widgit maker. Rich D. ------- From: wanliker... Date: Fri Jul 28, 2000 12:50 am Subject: Re: [sherline] End mill instead of fly cutter? << Would the surface look as good as if it was done with a fly cutter?>> No, there will be a series of swirls across the plate where you make each pass with the mill, the flycutter will leave a series of grooves where it cuts, With either the mill head needs to be accurately trammed with the table or the surface will be concave. If the job will permit it, use either, then sand the surface on a flat plate. Make your own flycutter, it is a good project to learn on. bill ------- From: Ron Ginger Date: Fri Jul 28, 2000 8:27 am Subject: Re: [sherline] Re: End mill instead of fly cutter? videos... wrote: > The stock is 1/2" and the biggest end mill I have is 3/8", it will > take 2 passes, should I try it any way? Sure, this is very often done. Even with a fly cutter some work is so wide that one pass doesn't cover it. Take a look at any of Rudy Kouhoupt's articles in HOME SHOP MACHINIST, he almost makes a 'trademark' on his projects of the mill passes. He does them very neatly, and very uniform and the projects have a nice look -- almost like 'engine turning' on old work. I asked him about that finish and he very consciously figures out the pattern across each part so the mill lines come out uniformly spaced. He does not sand the finished surface. You must of course have the machine lined up very well or else the mill marks will be grooves and that is bad. ron ------- From: Marshall Pharoah Date: Tue Aug 1, 2000 10:52am Subject: Re: How do I machine a radius? Rich, you can make a short post which will fit in the t-slot of the table on your mill and fit through the hole of your stock. By holding your stock with your hands, you can manually revolve it into the cutter to create the radius. Take real light cuts, and maybe even make an adjustable clutch with flat/lock washers. Scribe it and use a hacksaw and file to get it close first. You can get a little more control by making a longer handle. This is something I've done on a larger mill. The key is to take real light cuts so that you maintain control of the piece and don't let the cutter grab it. You could always make a simple rotary table if you're going to do a lot of this, but for a few, you can feed it by hand. Marshall ------- From: Ron Ginger Date: Thu Aug 24, 2000 4:16pm Subject: Re: My 1/4" collet and end mill are stuck in the headstock! I think your only choice is to hit it harder! Make sure the headstock is supported so the force goes completely into the collet- I would unmount the headstock and place it on a firm benchtop in a way that when you hit the drawbar you are driving the whole headstock into the bench, that should put all the force on the collet. Hitting it while mounted on the mill column will mostly shake the column I would use the drawbar, not a brass rod to do the hitting. Be sure the drawbar is well screwed into the collet so you load as many threads as possible- if its only a turn or two in you will likely ruin the thread in the collet, the drawbard or both. Using a rod, even brass, will place all the load on the top thread, possibly ruining the collet. I assume there is a mill in the collet. Maybe a thin rod, through the collet, to hit the top of just the mill will push the mill out. Since its a 1/4" collect this would require a rod slightly under 1/4", and the length of a drawbar. Thats going to be so long and skinny it likely will just bow, but maybe worth a try. There was a discussion here a few weeks ago about how hard to tighten the drawbar. You have shown it's possible to make it too tight! ron ------- From: Dave Martindale Date: Thu Aug 24, 2000 4:48pm Subject: Re: My 1/4" collet and end mill are stuck in the headstock! If you're going to hit the drawbar (or a rod that replaces the drawbar) very hard, it would be a good idea to support the headstock so that the *spindle* end takes the force, not the headstock base. If the base is what takes the load, the impact is transmitted from the spindle to the base through the headstock bearings, and enough impact will damage the bearings. Another thought: use something like a large C-clamp or woodworker's pipe clamp to provide pressure without impact. The headstock bearings should take a lot of steady pressure (without impact) before being damaged. Dave ------- From: Bill Miller Date: Thu Aug 24, 2000 8:14pm Subject: Re: My 1/4" collet and end mill are stuck in the headstock! Dan, I just did the same thing yesterday with my fly cutter. Fortunately, I have a brass rod that I use for squib rounds in my pistols that just fits through the spindle ID. Two good taps with a hammer had it out. I think the draw bolt was flexing too much and absorbing the impact on it. Bill ------- From: Charlie Lear Date: Thu Aug 24, 2000 8:34pm Subject: Re: My 1/4" collet and end mill are stuck in the headstock! On Thu, 24 Aug 2000, Dan Gustafson wrote: >> Great. I managed to have gotten my 1/4" collet and end mill stuck in the headstock of my mill. I tried cooling the entire thing in my freezer hoping the metal would change size enough for me to tap it out but I still cannot get it out. I have tapped good and hard on the big long screw that pulls the collet into the taper but it aint movin. What do you guys do in this situation? Is there any way to prevent this from happening? Happens to the best of us, more often than people care to admit! As you have seen, on shallow tapers there isn't a big difference between not quite tight enough and too tight. On my bigger lathes (3MT and 6MT) it is easy to slide a heavy bar up the spindle hole and cleanly knock it out without much drama. On a Sherline, you aren't going to get much mass in a 3/8" bar, so the method doesn't apply. DO NOT hit the end of the drawbolt with anything metal or heavy. (You won't damage the drawbolt or collet threads unless you're way too angry or have the drawbolt way too slack.) You'll get away with it a few times but sooner or later you will damage the headstock bearings. The same applies for poking a bar of anything down the spindle and whacking the end of the bar. What needs to be done is to support the nose of the spindle, while applying force to the end of the drawbolt. What I do - and this is by no means the only way of doing it, or a "correct" way of doing it - is to get a 2" piece of 3/4" OD steel tube, slip it over the milling cutter and collet, and butt it up against the spindle. My offcut is small enough to not interfere with the spindle threads. Slacken off the drawbolt by 1/8", put the solid end of an 8" G-clamp against the tube, and tighten the clamp screw against the end of the drawbolt. A couple of turns and she'll pop out with no drama at all, and no stress on the headstock. I've only used this method with collets, as I haven't (yet) got a flycutter or boring head jammed up the spout. When I do, I'll have to figure a way of applying force to the end of the spindle past the tool. Probably a piece of aluminium plate shaped like a C and butting up against the flat part of the spindle register will do the trick. In ordinary use (eg 99% of the time, when I haven't been too heavy-handed in the screwing-it-up-tight department) I just slacken the drawbolt two turns and tap the end with a plastic-faced hammer. For the next question: how do you stop the mill spindle from turning when you have a spanner on the end of the drawbolt? 8-) Hope this helps, Charlie ------- From: Ron Ginger Date: Fri Aug 25, 2000 9:25am Subject: Tramming the head (tutorial) "Rich D." wrote: > Bill, > The spindle is not at 90 degrees to the table. Fix a dti in the > spindle and sweep the table/make adjustments. I think this is a topic that could use some more explanation for the new guys. This operation is called 'tramming the head' and is required on all vertical milling machines, even the biggest of them. Sherline is no exception if you are looking for the most accurate work. The idea is to be sure the spindle axis is exactly perpendicular to the table. It can be off for several reasons. 1) the mount of the headstock is designed to swivel. In the lathe position this is used to trun tapers, in the mill position it really is not a usefull adjustment. A key is fitted to the head to hold it in a straight position, but its likely this is not 'perfect' 2) the vertical column is bolted to a mounting block with 4 screws. There is no pin to align this, so its possible it can be slightly off. If you have the optional swivel plate here it can be way off. 3) The base block that mounts the column to the base could be milled slightly off, or could have a chip under it that makes the head lean off 'true north' So, there are several places that can cause the head to lean. You determine the lean by putting a DTI into the spindle at an angle then use it to sweep as large a circle on the table as possible. If the head is perfectly vertical the reading will be the same for the entire sweep. If there is error it will show as the indicator being 'long' on one side and 'short' on the opposite side. Your job is to 'simply' adjust something until the reading is the same all the way around the circle. Easier said than done, if you want it real close. If the reading shows a lean to the left or right the headstock mounting can be swiveled, just as for turning taper. I read somewhere about a fine adjustment block for this that would also be a great addition in lathe mode. Essentially a plate with 2 tapped holes arranged to push on either end of the headstock body to make fine adjustments. If the column is leaning forward or aft the only adjustment is to shim or file under the base block. Anytime I want to make very accurate parts I do a quick sweep of the head first. It does not take a big hit to knock it off true. ron ------- From: Marshall Pharoah Date: Fri Aug 25, 2000 10:03am Subject: Re: Tramming the head (tutorial) Very good. You can also shim between the vertical column and the base block. This might actually be a good spot for a permanent fine adjustment? Marshall ------- From: Date: Fri Aug 25, 2000 10:56am Subject: Re: Tramming the head (tutorial) Make sure that the front to back table error is caused by the column and not the table before you go too far. With an indicator touching the table surface, run the table forward and back. On my 5400 mill, this showed a difference of about 1 thou. With a mill tooling plate in place, I got the same results. I chose to mount the tooling plate with a shim under one edge to correct this. Final tramming of the head then required only getting the headstock parrellel to the vertical axis in the left to right directions. This required TWO checks. First, make sure the column is truly vertical to the table by mounting an indicator in the spindle and without turning the spindle run the headstock up and down while indicating on a known good square resting on the table. Adjust by loosening slightly the four mounting screws and tapping into alignment. After the column is truly vertical, adjust the headstock angle (the one used for taper turning on the lathe) using the tradition sweep method. -Brian ------- From: Rich D. Date: Sun Sep 10, 2000 11:33am Subject: Re: cutting t-slots for a new sherline milling table Jason Spangle wrote: > Hello Everyone, I'm making a tooling plate for my sherline 2000 mill. I've purchased some 3/4" thick 4-1/2" wide 6065 aluminum, and once I have the length cut down, I'll have a slightly larger/longer table. I'll be using some old mill that's big enough to handle fly-cutting this piece, I'm waiting on the fly-cutting until I have all holes drilled. But then I thought about putting two or three T-slots down the length. Now how do I go about machining T-slots? Is the size measured on the smaller cut or larger (bottom) cut? Do I first run an end-mill down the length so that the T-slot cutter will have room to throw chips out? I think I'll have enough room to have three slots machined (to standard Sherline spacing of each) and then I'll fly-cut both sides since I'm sure there will be a slight warping from heat right? thanks everyone, Jason < Jason, cutting T slots is a two step process. The vertical slot is done first with an end mill or a radial cutter in a horiz miller and then a T-slot cutter is run down the center of the slot to cut the head of the T. The 'Size' is usually given as the T bolt shank diameter, so the slot may be wider. The Sherline T slot is a small special size. A cutter will have to be made from drill rod or you could step up to the smallest commercial size: for 1/4" bolts. Fly cutting your alum. slab may warp, but only because you cut away stressed material on one side. I understand that Sherline will not supply a longer table because of this. Rich D. ------- From: Kevin P. Martin Date: Mon Sep 11, 2000 10:53am Subject: RE: cutting t-slots for a new sherline milling table The Sherline T slot is a small special size. A cutter will have to be made from drill rod or you could step up to the smallest commercial size for 1/4" bolts. I seem to recall that I found a "keyseat cutter" that, although not identical to the Sherline T-slot size, would be able to cut an acceptable T-slot once the main slot had been milled out. The only problem is that it has a 1/2" shank (whice necks down near the cutter). I was planning on buying another 3/8" end-mill holder and boring the hole out to 1/2" but I never got around to it, and still haven't used the cutter! Kevin Martin ------- From: Date: Sun Sep 24, 2000 1:38am Subject: Lathe ops on a mill Is it possible to do lathe operations on a mill? I currently own a Sherline mill, and was thinking about doing lathe operations by holding stock in the spindle and the tool in the mill vise. I know finding centre would be a pain, but is it possible? Keith ------- From: Marcus & Eva Date: Sun Sep 24, 2000 9:39am Subject: Re: Lathe ops on a mill Hi Keith: Sure it is!! I've done it often, when I've had a setup in the lathe that I didn't want to disturb, and just needed a quick cut on something else. I've also done CNC turning on a Sherline mill equipped with Flashcut and the horizontal milling base. Worked like a charm on a bunch of plastic parts that I had to make. The only thing that you can't do easily, is tailstock operations. Cheers Marcus ------- From: Date: Mon Sep 25, 2000 8:30pm Subject: Re: Lathe ops on a mill Okay, now that I know it can be done, do the four jaw and three jaw chucks mount up to the mill's spindle? Thanks for the replies, it is greatly appreciated. I'm really glad I found this e-group. Now I can share my hobby with others that actually share the same interest. Keith ------- Date: Fri, 5 Jan 2001 18:41:52 -0800 From: "Yasmiin Davis" Subject: RE: Advice for novice >> I've got some ground stainless steel shaft 1/4" diameter by 6" long. I need to drill a 1/16" hole through it for a dowel pin, thread the end of the rod about 3/4" (1/4-20) and cut 2" off the other end (I need 4" shafts and this came in 6" increments from the Small Parts catalog). Anyway, I've got the Sherline lathe & mill, carbide/TiN drills, and a standard bench grinder, cutoff saw and drill press. So far I've only worked with aluminum, so if there's any advice people on this list would care to throw my way before I hurt myself I'd appreciate it ;-] Thanks in advance, Eric Solberg << You need to make a jig. Take a piece of whatever and mill a 45 degree V ( 90 degrees total) into it about 3/4 of an inch deep. Then drill a 1/16 hole into the bottom of the V and out the other side. Then clamp you rod to the V with the flat side of the jig on top and perpendicular to the plane of the drill. Center punch the rod through the 1/16 hole with a 1/16 transfer punch. Then drill the hole going slowly till the hole in the rod is well started. If you really want to get fancy you could make a drill bushing and drill a bigger hole into the bottom of the V. Then make a drill bushing that will reach down and touch the rod. This will cause the drill to have less of a tendency to wander. There are ways of sharpening a drill that will tend to prevent this but that's really going a bit over the top for a 1/16 th drill. I am sure you will get some other methods that will work as well or better than mine but then that how we all learn. Yasmiin ------- Date: Sat, 06 Jan 2001 03:50:13 -0000 From: "Flosi Gudmundsson" Subject: Re: Advice for novice The simplest way of drilling a hole on cener of a round stock is to mill as small a flat on it as possible and then use eyesight to senter a center drill over it. After some practice this is rather eazy. A general advise regarding machining is to use sharp HSS tools, good cutting fluid and don't get tangled in the steel wool while it is forming. It can easyly cut off fingers. SS is probably not the easiest stuff to machine, but I know nothing that gives better finish. Flosi ------- Date: Wed, 10 Jan 2001 02:55:35 -0000 From: "Robin " Subject: Turning on mill... No, not powering up a mill, but rather using a mill as a lathe :) Tonight I decided to prepare a blank arbor for reaming on a lathe to produce an endmill arbor. I don't own a Taig lathe, and all my blank arbors (ordered from Taig) had about +/- 0.002" run out. Obviously, I would be unable to place the arbor in a collet or chunk of another lathe and drill/ream it as the endmill would then have the same runout, which would be unacceptable. To obtain a true OD, I placed a lathe tool bit in my milling vise, and screwed the blank arbor onto the mill head. I then turned on the mill and very slowly cut the OD of the arbor with the lathe tool using the Z feed. I took off about 0.002" at a time until there was nothing left of the original OD. Now the OD of the arbor has a runout of +/- 0.0005". Just thought someone might want to know :) Regards, Robin ------- Date: Wed, 10 Jan 2001 19:31:44 -0000 From: "Eric " Subject: How do you use a "center finder"? I recently purchased a Starrett center finder, which is basically an edge finder with a pointed end rather than the standard straight end. I am familiar with how to use the edge finder by bringing it to the edge of the workpiece with the spindle running and waiting for the abrupt "jog" to indicate your position. How does the center finder work? I can't find any information on it. Thanks, Eric ------- Date: Wed, 10 Jan 2001 15:08:07 -0500 From: Stan Zdonick Subject: Re: How do you use a "center finder"? At 07:31 PM 1/10/01 +0000, you wrote: >How does the center finder work? I can't find any information on it. Chuck the workpiece in the lathe with the center marked, usually by a punch. Roughly center the piece in the 4 jaw with the center finder near the mark. When you feel you're really close, insert the point of the center finder in the punched mark. Rotate the chuck slowly and the center finder will greatly exaggerate the error. Adjust the jaws until the center finder will no longer deflect when the chuck is rotated. Simple, fast, accurate. I'm sure there are pictures of this operation somewhere on the net. -------- Date: Tue, 30 Jan 2001 12:13:40 -0800 From: "Craig Libuse" Subject: Re: Sherline Mill Labled Wrong? >>"any opinions? Do I need to relable the Y-Axis, let sherline know, or >>am I looking at this wrong?? thanks! tauseef" Dear Tauseef, The Sherline mill handwheels are labeled in the same traditional manner as a Bridgeport or any other mill. It's not that the numbering system is "wrong" so much as that it doesn't really work in terms of a Cartesian coordinate system unless you think of upper left hand corner of the table as the 0,0 point. That way, all your X dimensions are positive and all your Y dimensions are negative. Cranking either handwheel clockwise makes the positive X numbers get larger and the negative Y numbers get larger, which is correct. If you placed the 0,0 point in the lower right corner, both of the handwheels could be considered "wrong". Placing 0,0 in the center of the table as you had it makes one handwheel right and one wrong. I am told this is referred to as the "machine coordinate system". I hope this reduces confusion rather than adds to it. Craig Libuse, Sherline Products ------- Date: Wed, 31 Jan 2001 23:37:28 -0000 From: ballendox~xxyahoo.com Subject: re: re:Re: Sherline Mill Labled Wrong? Craig, again, there is NOTHING WRONG with the HANDWHEELS! The Y axis engraving (on the machine base) is wrong! Homing location has nothing to do with this! It IS true that most machining centers (vertical, like the s/l mill) home to the most positive axis location. This means the coordinates used will be ALL negative (until reset by program or operator). This is quadrant 3 of the cartesian coordinate system. Ballendo P.S. (snips/inserts below) >>"The next generation of machinists is in our classrooms now. MANY >>are using Sherline equipment. Shall we train them in >>an 'outdated' "machine coordinate" setup, or prepare them for the >>REAL world? Suggesting that the origin be placed in the upper left >>corner is WIERD!" >but notes that you should be aware that not all machine >use the same location on the machine tool for the home position. The >example he illustrates shows a system where the upper right corner >of the table is zero and all X and Y points have negative values for >programming purposes. There are 8 possible (normal) Home positions; the 4 corners of travel with z high, and the 4 corners of travel with Z low. Industry standard is z moving upward is positive, downward is negative. Because of this, virtually ALL vertical mills and machining centers home z to the top of travel. This eliminates four (of the possible eight) home locations. The remaining 4 home positions WILL affect the 'signs'(plus or minus) of the coordinates used, BUT travel direction and orientation WILL NOT be changed! the 4 possibles: home coords LL = +X,+Y (common for CAD, engravers, routers) UR = -X,-Y (common for vert. mills and VMC's) UL = +X,-Y (not commonly used by machinists) LR = -X,+Y (not commonly used by machinists) The one additional sometimes used home position/program zero is CENTER of travel. This just means that the coords will be pos or neg depending on which direction you go on the part/table. It DOESN'T change the Labelling of the axis travel directions... >but it does show that the coordinate system for programming can be >somewhat flexible. Flexible, yes. But not willy-nilly... >It is in our best interest to follow whatever is the industry >standard. >Craig Libuse Sherline Products Yes! And that's why I've spent so much time on this thread... ------- Date: Fri, 02 Feb 2001 13:02:36 -0000 From: ballendox~xxyahoo.com Subject: RE: New Member Paul, since you are cutting wood, consider adding a dremel mount to the mill (in place of the spindle). The higher speed should give you great results. Of course, if you're using exotics like boxwood, cocobolo, ebony, etc. or fine grained stuff like pear, apple, holly, etc. you may have fine results with the slow speed(for wood) of the stock spindle. The suggestion for a "backup" gear is a good one (or use a 'stack' of gears). Masonite (tempered hardboard) is cheap and works well. I posted an ascii drawing of a dremel mount to Alan M awhile back. maybe he can re-post it. A nice, easy project, it alows some things to be done which are difficult with a stock spindle. Fine woodworking magazine had an article on wooden clocks some time back which detailed a number of ways to cut gears. Also things to use instead of 'involute style' gears. Many wooden gear trains use a lantern pinion and a different tooth style than metal gears. Do keep in mind wood movement! Your 'round' gears may turn oval and bind. Sometimes you can play with this and make the 'ovals' work together. I've even seen elliptical gears... There is a shareware gear cutting program available on the web. try a search. It's a UK listing. Hope this helps. Ballendo ------- Date: Fri, 02 Feb 2001 21:27:17 -0500 From: ron ginger Subject: Re: power feed for mill? Chuck & Joanne Johnston wrote: > Does anyone have details on a power feed attachment for a mill ? > Would like to add a power feed for smoother cutting on both axis on the > mill. Any ideas or tips ? > I don't like to spend the 400+ bucks that it takes for the CNC setup. Buy a battery operated electric screwdriver. Insert a hex nead socket screw in the center of each handwheel, and lock it with locktite. Put the right size allen driver in the screwdriver, and poke it into the center of which ever handwheel you want to power. Most of then have forward/reverse and some range of speed settings. Might be helpfull to grind some relief into the end of the allen driver, like those "ball drive' hex sets so alignment is not critical. ron ginger ------- Date: Mon, 5 Feb 2001 01:21:35 -0800 From: "Eric Solberg" Subject: Achieving good finish on mill I'm having trouble getting a good finish milling 6061 aluminum. (1/2" thick rectangular bar stock) I'm using 3/8" HSS end mills (from Sherline) running at 2000 RPM and depending on the direction I cut will either end up with a rough finish or a shinier finish but with lots of bumps from the climb-cutting. Either way I end up with a lot of filing and sanding, but on the parts I'm making this is difficult. Any advice for getting the finish better the first time? If there's a particular type of end mill that will make all the difference then I don't mind spending some money on it. I have the MSC catalog but don't know the parameters to look for to get a better finish. Thanks, Eric Solberg ------- Date: Mon, 05 Feb 2001 10:41:15 -0000 From: ballendox~xxyahoo.com Subject: Re: Achieving good finish on mill Eric, first be sure the gibs are adjusted correctly. Climb milling stresses a machine more than conventional cutting. Then check to see if you have minimised leadscrew backlash(at the nut AND the handwheel). Next be sure all machine adjustments are tight (spindle/head setscrew, etc). Be sure to LOCK any "unused" axis! Are you cutting 1/2 width of the endmill (3/16 wide passes)? Are you too deep (each pass)? means have you tried other width/depth combinations to see if one works better. NOW, AFTER you have checked all of the above, think about changing the cutter. Are you using 2 flute and lubrication? Wd-40 works well with 6061. Speaking of this, are you sure it is 6061? Some aluminums are terrible to machine. The sherline mills are good tools and capable of finishes needing no additional work. If the suggestions above don't fix the problem, try to talk to someone in your area who may be able to 'see' something we can't get from an email. Hope this helps. Ballendo ------- Subject: Re: pc bds w/ sherline Date: Sat, 14 Oct 2000 07:09:30 -0000 From: ballendox~xxyahoo.com To: KM6VVx~xxarrl.net Alan, I know you didn't ask, But Since it looks like you'll be milling pc bds soon... :-) Try making a Dremel adapter to fit the sherline mill. The speed will VASTLY increase the quality of your results. I'm including an ascii art example: made from alum plate. And a couple of cap screws. Mat'ls. Cast alum is better but wrought plate will be ok. 6061 typ. 1ea.-2.75w x 3.00l, 1.00 th. to 1.25 th. alum. 1ea.-2.75w x 3.00l, .500t alum. 2ea.-10-32 x 1 SHCS Note: The old dremels have a 3/4-16 thread on the nose. the new ones use 3/4-12. Tap is about $12 from msc, travers, enco, or the like. You COULD mill the thread with your CNC! But the cutter will cost about the same, or more. :-( The sherline head mount pin is .500dia. and 1.188 or so long. So if you use 1.00 thick alum you will need to screw the dremel into the mount before mounting it to the mill.(so you can turn the dremel) Not shown on the drawing is the hole for the setscrew which holds this thing to the mill. Use the sherline orig. head to get the dims. for this. This is a basic version. If you'rew going to do a lot of boards, you will want to redesign to have the dremel "float" vertically and use a nosepiece to control the depth of the engraving into the pcb. |--1.00+ --| __________ | | | | ___ bore .500 for sherline mount pin | | / | | / |----------|/ __|____ _ ___|____ | | |----------| | | | - | ____ Tap 3/4-XX for Dremel | | | |---1.125-----| / (see note above) | | | | min. | / |_____|_|__|_____________|_/_______ ___ | | | < | > | | |_| < | > | .500 |____|___|__________<____|____>____| ___ | | With this setup mounted on the Z axis, I use a .500 cast alum(so it stays flat) "table" (mounted to the sherline mill table w/ spacers so it clears the motors/handwheels) to give me something flat to mount the pc bd mat'l to. I use 1/8 tempered masonite(smooth both sides) as a "backup" material under the board. Think and tinker (on the web) sells bits, board mat'l and thr "real" backup stuff. Good luck. Hope this helps. Ballendo ------- Date: Tue, 06 Feb 2001 15:35:06 -0000 From: gavin.Eyrex~xxrsl.com Subject: Large Radius Cuts I am trying to make some small webbed parts that have edges curved at a radius of about 48". The parts themsleves (train connecting rods) are only about 2" long. I can get the curves on the outsides by hand filing - but to get curves on the pocket really needs me to be able to move the piece under the cutter so that I cut a small portion of a large radius. I have thought about doing small stepped cuts - ie move .030 on X and then .001 on Y then .025 on X and .001 on Y but wondered if there was a better way. Thanks Gavin Eyre ------- Date: Tue, 06 Feb 2001 11:54:55 -0500 From: "Rich D." Subject: Re: Large Radius Cuts Gavin, I have made contours by hand coordinate stepping. But to minimize the stair stepping look the number of steps has to be enormous. This is a job for CNC, for sure. A 48" radius is very large and .001" steps may be too much. I'm setting up a CNC Sherline 5400 now for this type of work. Rich D. ------- Date: Tue, 06 Feb 2001 18:29:45 -0000 From: n2562001x~xxyahoo.com Subject: Re: Large Radius Cuts Gavin: A 48" radius over a 2" span will almost be a straight line. I think you will need to scale your radius for the item to look right if I understand your project. If you scale the radius it will probably be managable using a rotary table. If need be you can bolt a plate that is well beyond the edge of the rotary table to get the radius you need. Jerry Kieffer ------- Date: Tue, 06 Feb 2001 11:18:19 -0800 From: Alan Marconett KM6VV Subject: Re: Large Radius Cuts Hi Gavin, I'd have to see the drawing, but I think you might want to do something like that on a rotary table. OR, mount the part on a pin through the center of the radius, and move the part by hand through the arcs you want to cut. The third way would be to use CNC! The radius is 48"? .48"?? More on the rotary table approach. You could use a large timing belt pulley, mount it on a short shaft and bearing that can be bolted to the ways, and use a single tooth to lock the table at various angles. bolt your part on the big pulley. Then mill holes along your arcs. Connect the holes, you've got your arcs. Driving it with a belt and a small pulley on a handwheel MIGHT give you enough control of the table to make continuous cuts. This makes what might be considered to be an inexpensive indexing head (or rotary table, with the belt drive). Enough teeth on the big gear, and you have quite a few "locked" angles to work from. Calibrate the small pulley, and you've got even more! Hope this gives you some ideas. Post the drawing, we might come up with a few more! Alan KM6VV ------- Date: Tue, 06 Feb 2001 19:19:56 -0500 From: Jim Ash Subject: Re: Large Radius Cuts Granted the Sherline is kinda small for it, but don't overlook lathe filing. In one of Guy Lautard's books, he describes a stepping method, followed by filing to smooth out the steps. His trick is to calculate the steps accurately, blue the work after stepping, then file until the blue is gone. There' no reason it shouldn't work for you on the Sherline. Jim Ash ------- Date: Wed, 07 Feb 2001 00:45:48 -0000 From: ballendox~xxyahoo.com Subject: re:Re: Large Radius Cuts Gavin, I agree with Jerry that you may want to 'scale' the radius. Much of the 'art' of modelmaking is knowing when to depart from "strict scale" measurements! If you have already taken this into consideration (or don't have a rotary table), here's a way: Turn the y axis of your mill into a "tracer" configuration, like a taper attachment on a large lathe... Then you can use one of your "outside filed" curves to cut the inside pocket curve(s). I think I described this in an archived message, but here goes. To do this, remove the y leadscrew from the machine. Using the 'disk' that the leadscrew went through(1/4 hole) fasten a "pointer" which will be a block of metal with a tapped hole for the holding screw, and a vee-shape which 'points' towards the mill table. _______ /\ | | / \ |_______| | || | | || | |_||_| |_||____| ________ | | The "O" is a threaded hole for a screw | O | which passes through the leadscrew hole |________| in the 'disk' that the handwheel rides against. Now fasten a "hand filed template" using the front t-slot (on the mill table) This will be a flat piece of sheet metal, or flat stock, which has 2 holes for mounting "off the front" of the mill table. The shape to be 'traced' should be machined (filed, in our CURRENT case; it could be a "wavy" shape, or a taper, etc.) in the edge 'facing' the pointer. Now you can see that if the mill table is "gripped" in your left hand (fingers around the back of the table, thumb on the front of the mill base), you can 'pull' the template (with table) into contact with the 'pointer' you mounted in the disk (which formerly held the leadscrew). If you use your right hand to screw the x axis handwheel, you will see that the table is "following" the template curve! Mount your work in the appropriate position on the mill table and "you've got it!" Hope this helps. Ballendo P.S. This might be a nice "aftermarket" accessory for sherline to offer. They could replace the left hand "spring" with a REAL spring or tension device. I see something adjustable, possibly "screwed into" the column support block. You could do this also, if the idea of your hand in the "cutting" area bothers you. IMO, the forces involved make for a safe operation if care is observed... P.P.S. You can also "work this out" using the "stop" screw in the machine base to hold the pointer (which is now MADE FROM a piece of angle). Position the table with the handwheel so the table is near (a little forward of) the proper position for cutting, THEN remove the handwheel. You can fine tune the leadscrew projection (if it is getting in the way) without the handwheel attached. You "may not have to" remove the leadscrew. It will depend on the size of the part, and the shape. One advantage to this position is that your hand will be "farther away from the action". It is not difficult to remove and replace the leadscrew, and going that route will give more versatility to the operation. ------- Date: Wed, 07 Feb 2001 07:57:05 -0000 From: videosx~xxmail.giga.com Subject: Re: Large Radius Cuts I don't understand your part completely so maybe this is not what you need. The best and most precise way of obtaining long radiuses is by the method astronomical telescope mirror grinders use. You start with 2 glass or metal discs of the same size, add abrasive powder in between and rock the top disk forward and back, overhanging the edges by about 1/3 diameter. The top disk gets concave and the bottom one gets convex. This can be done with rectangular shapes also. You can get a 48" radius in an 8" pyrex disk in about 1 hour with 60 grit abrasive, then use finer abrasives to get a better surface. If you overshoot your radius just put the top part in the bottom and the bottom part in the top and grind a bit to return to your desired radius. This is better explained in a telescope mirror grinding book or do a search in the net, I recall there where several places that explained this. Hope this helps. Rogerio Odriozola ------- Date: Thu, 8 Feb 2001 14:30:09 -0500 From: "Dan Statman" Subject: Re: Re: learning manual [MILLING] Actually, All of my rings are done by hand. I don't even have a rotary table, hell I don't even have a mill, just the milling column for the lathe. I use a vise, and my dial caliper and a scribe to mark of the rotational angles around the perimeter of the ring using a little trigonometry and the outside diameter of the ring. All of my curved surfaces (except the inside and outside diameter curves) are ALL filed by hand. It takes me a very long time to make certain styles of rings. There are however, some designs which I cannot make on my current equipment without converting them to CNC. I just don't make those designs, I am sure somewhere there is a non-CNC machine costing many thousands of dollars that could maybe be made to cut the designs I want, but it sure as hell would be easier, cheaper, and quicker with a miniature CNC mill and rotary table. I still wouldn't bother cutting a domed profile ring with a CNC as I can do it MUCH quicker with a hand file. Daniel J. Statman, Statman Designs http://members.rennlist.com/statmandesigns -------- Date: Sat, 10 Feb 2001 12:34:19 -0500 From: "Bill Rutiser" Subject: Re: Chips > Question: How are you folks protecting the dovetails, etc.? I know that some of the larger mills have covers over their dovetails to keep the chips away. -- Jerry Jankura < Jerry, I usually attach an improvised cover with masking tape. For vice setups, I have a piece of material from a heavy Ziploc Brand plastic freezer bag. At the bottom, its taped to the back of the mill table. At the top its taped to saddle behind the spindle. This does a good job of keeping chips from the back part of the Y axis dovetails. I have also used two pieces of cardboard. One was taped to the table and the other suspended behind the spinple by a piece of wire. The upper cardboard hangs in front of the lower piece. This works well for long X moves but the cardboard must be matched to each range of vertical positions. Bill Rutiser Gaithersburg, MD, USA ------- Date: Wed, 14 Feb 2001 23:09:54 -0600 From: "Jeffrey C. Dege" Subject: Need some help... I'm playing with my new Taig lathe, building a simple little wiggler steam engine (one of Patrick Verner's plans, from www.steamengines.org - and btw, does anybody know what happened to his site?) The body of the engine is L-shaped - and I'm wondering how to deal with finishing the inside edges of the L. Yes, I suppose that since these are non-bearing parts I could just grind them flat and polish them up, but I'm doing this to try different things with the Taig. Fly-cutting the surface, of course, won't work, because the other part of the L will get in the way. Same problem with an end-mill. But looking at things, if I had a milling cutter that would cut with its side, I'd be able to reach the areas I need. I've got (as may be obvious) the Taig milling attachment and vise, and the 1/8" end-mill, but measuring the width with my calipers show me that the width is not consistent, it has a definite taper. So it is clearly not intended to cut on its side. So next I go looking through the MSC online catalog trying to figure out what milling cutters are actually intended to cut with their sides, and which of them would fit in the Taig. And it quickly becomes obvious that I haven't a clue which types of mills are intended for what. I see center- cutting, standard, regular, etc., and I have no clear idea what is what. So any ideas? What should I be looking for? ------- Date: Mon, 19 Feb 2001 23:01:05 -0800 From: "Cliff Griffin" Subject: Re: Problems Fly Cutting Chances are you have backlash in the Z axis, and the weight of the motor etc. isn't enough to overcome the friction from the slide. As you cut, you are creating enough vibration to shake rattle and roll that slide down a bit. If you were to rap the Z axis with a mallot and THEN go do your cut, it wouldn't have taken more--or a significant amount--on the second pass. That's for discussion purposes only--don't try this at home, though. You could also loosen up the gib, but that would have detrimental effects on operations that created enough force to lift the motor assembly, and that doesn't take much at all...so don't do that either. One acceptable way to overcome this is to lower the Z axis to where you want the cut to be, and then reverse the handwheel until you juuuust feel some resistance, then lock it. This, I've found to actually work. The play in the Z axis is the main reason I only use my Sherline mill for engraving anymore. I've recently rebuilt part of it so it's better, but for the most part, I'll wait a day or two until I can borrow a friend's Real milling machine. Cliff ------- Date: Tue, 20 Feb 2001 00:05:25 -0800 From: "David Goodfellow" Subject: Re: Problems Fly Cutting I called Sherline with the same problem. Joe Martin said my gib may be too tight, so that the weight of the motor was insufficient to bring it down. He suggested I loosen the gib just enough allow the motor to come down through the backlash. I did that and it worked, and so far have not had the problem Cliff mentions below. Doesn't mean I won't, just that it hasn't so far. Dave Goodfellow ------- Date: Mon, 19 Feb 2001 11:03:43 -0600 (CST) From: Tom Benedict Subject: Re: Setting up the CNC mill I like Nick's method of indicating an edge. I use an edge-finder with a 3/8" shank, but most of my cutters are mounted in individual arbors, so this makes sense for the way I work. I'll describe that later on in this e-mail, but just understand that there are lots of ways to indicate an edge, so if you don't like one, use another. Installation 2: Mounting material to the mill bed: Now that you know your mill axes are all aligned, it's equally important to know that your work is aligned as well. Quick caveat: Most of what I'll be talking about here involves rectangular workpieces. Some workpieces don't fit into this category, so take this with a grain of salt. One example is a round piece you're drilling a bolt circle on. Rather than spending time making sure the work is square and indicating an edge, you'll be spending time clamping it down and making sure you're indicated in on the center of the piece. I won't go into great details on how to do each of these, but will only hit a couple of common ones. You can attach work to a mill bed in more ways than I can describe. Some examples are vises, collet holders, strap clamps, and tooling plates. All of these require some sort of alignment. I'll go into a couple of them: Indicating in a vise: When you first put a vise on your mill bed, it's important to make sure it's square to the bed. You use a process very similar to the one used to square your mill column. Once again, there are lots of ways to do this, so your methods may vary. The basic gist of these have a similar thread: Start by putting the vise on the mill table, and snugging down the bolts that hold it down. You still want to be able to rotate the vise, but you don't want it to slide of its own accord. Next, mount your test dial indicator on your mill head. Move the mill table until the indicator point is resting against the fixed jaw of the vise near one edge. Note the reading on the indicator. Now move the mill bed until the indicator tip traverses most of the length of the vise jaw. Chances are it'll have a different reading. Tap the vise with a soft mallet to rotate it in the right direction. Now move the mill bed back in the other direction and note the way the indicator changes. This may take a number of iterations before you get close to zero deviation across the face of the vise jaw. This is where individual methods come to the fore. Joe Martin describes his way of doing this in his book, "Tabletop Machining". My own particular method isn't very fast, but it does result in a nicely indicated vise. I'd be curious what methods other people use to indicate a vise in to see how I could improve on my own techniques. Once your vise is indicated in, you know that any rectangular piece you clamp in your vise will have one edge aligned to your mill's axes. Indicating in a Clamped Workpiece: If you're using clamps to hold your workpiece to the mill bed instead of a vise, you essentially go through the same procedure, but instead of indicating on the fixed jaw of your vise, you're indicating directly on the edge of the workpiece. But the same basic idea holds. You measure, rotate the workpiece, measure, rotate, measure, rotate, ... until the test dial indicator indicates no deviation across the edge of the piece. (Quick side note: There's no such thing as "no deviation". What you want is "acceptably close". If you're roughing out something where the edges don't really matter, "close" may be several thou across a two-inch edge. If you're cutting something that will need to mate to other parts along its edges, "close" may be less than half a thou across a two-inch edge. "no deviation" is a relative term that only you can define.) Zeroing your Axes: Once you know your workpiece is aligned to your mill axes, you need to indicate some feature on the workpiece and make that your "zero" point. (Zero is in quotes because you may or may not actually want to set your axis zeros to that point. But this is the reference point for your part. All other measurements will measure from that point. Hence "zero".) Zeroing on a Corner: To zero in on a corner, you need some way to find two edges, one in the X direction and one in the Y. Nick already described a way to do this with a dowel pin. This is an excellent way to find an edge if you're using collet-mounted cutters: On Sun, 18 Feb 2001, Nicholas Carter and Felice Luftschein wrote: > Here's how I find edges: > In a 1/4" collet I mount a 1/4" dowel pin. I set the jog to .100, > and jog the pin close to the x-axis edge I want to set as zero. set jog > to .001 and jog the dowel pin until it pinches a piece of rolling > paper between the edge and the pin. remove the paper lift the z-axis, > move it over above the vise .126 (1/2 dia. of pin and thickness of > paper) then: > setx (enter) > 0 (enter) > x (enter) \ > to zero the motor (why do I have to do this?) > Then repeat the process for the y-axis. I'm used to using an edge finder, so that's how I indicate my edges. The approach is very similar. The only difference is in how an edge-finder tells you it has hit an edge. Edge finders typically have a shank of some size (mine is 3/8"), and an indicating surface that has been ground down to a particular diameter (mine is 0.200"). The indicator surface is on a separate piece of metal from the shank. The two are connected with a spring, and can slide against each other. Once you mount the edge finder in your mill spindle, start it turning at a relatively slow speed. (I use the second-slowest pulley position on my mill for mine. You may find another speed works better for you.) The tip of the edge finder will seem to wobble. You want to bring the edge finder up against your work so that the edge of the workpiece only touches the edge finder on the indicating surface. As the edge finder contacts the surface, it'll tap it and bring the indicating surface more in line with the shank. The closer it gets, the more on-axis the indicating surface will get. Once it looks like the edge finder is spinning like one single piece, slow down. Right at the point where it's inline with the edge, the indicating surface will suddenly jump to one side and make a buzzing sound. Stop there and raise your mill head. Since the indicating surface is 0.200" in diameter, move the mill table over 0.100" to bring the axis of the mill spindle directly over the edge. That's "zero" for that axis. Repeat on the other axis, and you now have a 0,0 corner. Zeroing on a Hole or a Cylinder: To zero on the center of a hole or on the center of a cylinder, you use a method closer to how you aligned the axes of your mill. Start by mounting your test dial indicator in your mill spindle. Mine fits neatly into one of the Taig collets. You want to be able to spin it by hand while taking a reading. By eye, bring the mill spindle over the center of the hole or cylinder (I'll be refering to it as a hole from here on out. Just understand it applies equally well to cylinders.) Start bringing the mill head down until the indicator tip fits into the hole. Rotate the mill spindle by hand, and see which direction you need to move the mill bed to get it closer to alignment. Once you reach a point where it's very nearly aligned, you can start using the reading off the test dial indicator. Just remember that if you have a 10 thou difference between readings 180 degrees apart, it means you need to shift the mill bed 5 thou. Once your test dial indicator has the same reading all the way around the circle, you know your mill spindle is centered on the hole. That's your 0,0 point. Vise Stops: Nick mentioned vise stops in his post. These are Really Handy (with intentional capital letters). A vise stop is a small clamp that clips onto the fixed jaw of a vise and cinches down tight. When you mount a piece of stock in your vise, bring it up against the vise stop and close the vise. Indicate in on the corner that's up against the vise stop and the fixed jaw of the vise. Set that to 0,0. Now if you remove that piece of stock and mount a different one, you know the 0,0 point on that one will be the same as on your last one. This saves lots of time, especially if you're making a bunch of simple parts. Quick side note: When your setup time gets to be longer than your cutting time, it's a good indication that you can probably do something to make your life easier, like use a vise stop. Finding the Surface: Finding the surface of the workpiece is easiest to do with your cutter mounted on the mill spindle. (One quick caveat: The reason each of my mills has its own arbor is because it let me set them all to the same height. I can change cutters, and know that the surface height for one is the surface height for any of the others. But I still indicate the surface height with the cutter I'm going to use.) For this you use the same technique Nick uses with the 1/4" dowel pin for indicating an edge. A quick note on setting the surface height with SuperCam: When you use the Set Surface command on SuperCam, it lets you use the mouse buttons to control the height of the mill head. Once you set the surface and hit return, it will move the mill head back to where it was before you did Set Surface. For this reason, it's a good idea to simply move the mill head down until it's reasonably close to the surface before you run Set Surface. Case in point: I was making a part that required me to change cutters several times, so I'd raise the mill head up to 4.000, change tools, then set surface. The surface was around 1.125". So it spent a LOT of time traversing the Z axis. It's easier if you move it close to the surface, THEN Set Surface. At this point your work is aligned to the mill axes, you have indicated in one corner of your workpiece, and you have a cutter installed on your mill. Next installation: Cutting metal! Tom ------- Date: Mon, 19 Mar 2001 09:31:10 -0800 From: "Nicholas Carter and Felice Luftschein" Subject: Re: How to mill aluminum Jim Lewis wrote: > I've been doing a lot of milling of 3003 aluminum on the Taig CNC > mill. Just 2D stuff on 1/16" and 1/8" sheets. The only cutter I found > that works decently is a 1/8" diam round single flute router veining > bit. But it's got zero helix so chips load up and weld after some > time. I also have to go real slow - like .01"/sec. I'm using the > second to slowest pulley. The edges are not bad but could be nicer. > Faster feed breaks the bit or stops the spindle motor. I tried 2 and > 3 flute standard end mills but result was not as good. Anyone know > the right cutter? And ideal feed and speed? Thanks. Jim Are you using lube? A friend who runs a large CNC mill has a air/lube setup on a timer so that every ten seconds a blast of mist and air hits the cutter. I find I have to hit the cutter with WD-40 frequently when doing work like this, and also brush all the chips away to prevent welding. 3003 is listed as a relative "C" in machinability in Machinery's handbook, and "B" in the Alcoa handbook - this may explain some of the problem. See our web pages http://www.casco.net/~felice ------- Date: Wed, 13 Jun 2001 16:00:55 -0400 From: "Rich D." Subject: Re: Paper used in a mill setup? gartner1x~xxhome.com wrote: > Have a basic question. I've noticed in pictures of mill setups that > quite often there's what looks like a piece of paper between a vice > jaw and the part. What's the paper for? To protect the work? To > compensate for irregularities of the part? All of these? Or > something else? Thanks, Jack Hi Jack, Paper or thin cardboard helps provide a better grip (increased friction) between the part and the vise jaws. Since parts and vises seldom have truly parallel surfaces when clamped tight, at slightly compressible medium will help spread the load to more surface. Another trick is to insert a narrow bit of aluminum between the part and the moveable vise jaw as this will insure that the pressure is truly forcing the part against the fixed jaw and not at the inner corners causing the part to be effectively loose at the opposite (outer) corners. Milling across the end will frequently cause the part to grab and swing up out of the vise. Clamping with the pressure centered on one side always insures that forces are equalized across the part. Rich D. ------- From: "Rich D." Date: Tue Jul 3, 2001 10:10 am Subject: Re: [sherline] Conventional VS Climb milling SavageHB308x~xxa... wrote: >> I'm trying to understand climb milling vs conventional milling. The way I understand, since my mill spindle turns clockwise (as I sit in front of it), and I'm milling the edge of a flat plate, I would mill the edge of the plate closest to me, feeding the material from right to left? This would feed it in opposite the cutter rotation, so the cutter is pushing against the material, rather than trying to pull it along. Is this the correct direction to go (for conventional milling)? Thanks! Arden << Arden: Yes that is correct for non-climb milling. The rubbing effect is greater tho as the cutter edge starts at zero chip load and gradually increases to max at exit. A dull edge will resist entering the material until there is enough force to do so. For climb milling, the edge is coming down over solid stock and can only enter at max cut (depending on travel) and leaving at zero. This way there is minimal rubbing on the material. It is the preferred method taking into consideration the machine stiffness and slide play. RichD ------- From: "Yasmiin Davis" Date: Tue Jul 3, 2001 11:42 am Subject: RE: [sherline] Conventional VS Climb milling I will not get into a debate about this other than to warn you that climb milling can be dangerous. Is the cutter enters the work it is going to take all the end play out of the lead screw as it pulls the work towards it. This can cause the cutter to take too deep a cut and if there is a lot of end play in the machine it can break cutters, rip the material out of the work holders, etc. Perhaps this isn't significant with a Sherline but since you may some day work with larger machines beware of climb milling. As to it being the preferred method -- I would dispute that statement. Regards, Yasmiin ------- From: "Charlie Lear" Date: Tue Jul 3, 2001 8:52 pm Subject: RE: [sherline] Conventional VS Climb milling On Tue, 3 Jul 2001 08:42:14 -0700, Yasmiin Davis wrote: >As to it being the preferred method -- I would dispute that statement. Depends what you are trying to achieve. Climb milling allows faster metal removal and generally a better finish. However the machine needs to be rigid and well adjusted - you are more likely to get that with a larger mill. Cheers Charlie Lear, Melbourne, Australia Hutt Valley Model Engineer Soc. http://steammachine.com/hvmes Eastern Bays Little Blue Penguin Foundation: same site /penguins ------- From: "Rich D." Date: Tue Jul 3, 2001 4:11 pm Subject: Re: [sherline] Conventional VS Climb milling Arden, I stand by my note on climb milling and being preferred. Also note I said: "taking into consideration the machine stiffness and slide play." This goes for any machine. I was not limiting my comments to Sherline gear. All this has been hashed out in the past on other lists many times. You have to know the equipment and use the proper methods to get the job done. Climb milling is definitely more aggressive and there is an element of mishap. The end result being a much nicer finish, less wear and less work. On small machines you may have to limit the climb milling to the final pass where the best finish with a worn cutter is had. On my 5400 Mill which is CNC only and I have no "feel", I reserve the climb milling passes to the final finish cuts and these are typically under .005". When manually machining in climb mode, the slide needs to be snug to keep the cutter from pulling the lash out. The Sherline has very little mass to help resist the intermittent pulls that a 200# Bridgeport table would have no problem with. Getting the job done involves many facets to the problem and getting experience is by far the best teacher. Use the tools and find out for yourself what they can do. My Dad once "caught" me using his power drill. The one thing I remember to this day is his comment "Don't baby it, push and make it cut". That has served me for the last 45 years. Nuff said. RichD ------- From: SavageHB308... Date: Fri Jul 6, 2001 8:37 am Subject: Re: [sherline] Conventional VS Climb milling jerry.jankurax~xxs... writes: >I can see no reason why you shouldn't cut on both pieces of the stock, >provided that you can clamp it properly. When you get down to a few mils >of final size, you might want to try climb milling to assure a really >nice finish on the material. Well, in my original question, I asked about milling one side with each direction change, but my piece wasn't wide enough for that. But I did clamp it with two more clamps, and then very carefully took a smaller cut on the "return", i.e. climb milling. It really does make a nice finish, but as I discovered it also cuts more for a given movement of the dial. No big deal; it's all part of learning! Thanks to all for the comments. Arden ------- From: "Kenneth Ault" Date: Sun Aug 12, 2001 11:24 am Subject: Milling a slot - beginner's question Hello - I need to mill a 0.25 inch wide slot in a piece of aluminum. Is it best to do this with an 0.25 end mill or with a narrower mill in two passes? I thought it might be more accurate to do each side separately with a narrower mill. If I use a 0.25 mill it will be cutting on both sides to the final dimension - will that lead to problems? Thanks for your advice. Ken Ault ------- From: "Dan Statman" Date: Sun Aug 12, 2001 1:39 pm Subject: Re: [sherline] Milling a slot - beginner's question Ken, if you need the slot to be exactly .250" then you should use a smaller end mill and bring the slot width up to your final dimension. If you use a .250" endmill you will get a slightly oversized slot (probably 5 -10 thousandths too big). You will get a better bottom of the slot finish with a single pass of the 0.250" endmill, and there will be a machining line at the overlapping point if you cut it with a smaller endmill with two passes. You can also practice a few times on a piece of scrap and see how it goes. HTH, Daniel J. Statman, Statman Designs http://members.rennlist.com/statmandesigns ------- From: wanliker... Date: Sun Aug 12, 2001 2:05 pm Subject: Re: [sherline] Milling a slot - beginner's question If you want an accurate slot, this is the correct way to do it. A quarter inch mill will cut oversize if used in this fashion, also the side walls will usually be rough, due to chip problems, and mill deflection with changes in cutting feed. bill ------- Date: Tue, 23 Oct 2001 22:20:05 -0400 From: "Rich D." Subject: Re: Cutting a inside/outside radius on a mill >How do you set up the work and then how do you cut the radius >on a piece of stock with the mill. I have a turntable , but >can,t figure out how to use it for this process. >Any thoughts would be appreciated! Regards, Joe Joe, first you have to know the radius. This will be the center of rotation. The work piece is clamped to the rotary table and adjusted to obtain the radius required at the position you may have marked the piece out for. Using an endmill, cut your radius by moving the x or y mill axis toward the radius and turn the rotary table for each pass. RichD ------- Date: Tue, 23 Oct 2001 20:39:10 -0700 From: Alan Marconett KM6VV Subject: Re: Cutting a inside/outside radius on a mill Hi Joe, assuming chuck mounted "face up" (like looking at a phonograph record) on the ways, and an "outside" radius: 1) Center the "center" of the part radius you want in a 4 jaw chuck mounted on the rotary table and perpendicular to the Z (vertical) axis of the mill. 2) Position the cutter (end mill) on the above center line in 'Y', and to the right of the work piece. Bring the cutter down to the same level as the radius wanted (Z). 3) Rotate table so that start of arc is aligned with cutter. 4) Feed cutter in X until first required depth of cut, or radius is reached. 5) Rotate table Clockwise (viewed from Z or TOP) until end of cut. 6) retract cutter in X. Repeat steps 3 - 6 above until radius is finished. The key is that the rotary table is set up to "rotate" on the center of the radius we want. We want the cutter to "follow the radius", so we ultimately want the cutter's edge to be at the radius we want. Table rotation does the cutting. A four jaw chuck may not be appropriate to hold the work, use t-nuts and clamps as appropriate. For example, a rod end (piston rod) would require a "fixture"; a plate clamped to the rotary table, with a "pin" with enough head to hold the rod end in place (and perhaps another pin in the crank end), and allow the end to be cut through the 300 or so degrees wanted. One would first "center" on one end of the rod, cut the radius, then center on the other end, and cut it's radius. Alan KM6VV ------- Date: Wed, 24 Oct 2001 09:27:04 -0700 From: "Craig Libuse" Subject: Re: Cutting a inside/outside radius on a mill >I have a turntable , but can,t figure out how to use it for this process. Joe, You can find instructions for use of a rotary table at www.sherline.com/3700inst.htm It is for Sherline's table, but the instructions for tool offset and so on apply to all rotary tables. HTH. Craig Libuse Sherline Products ------- Date: Wed, 28 Nov 2001 08:50:06 -0800 From: "Marcus & Eva" Subject: Re: Milling Problem Original Message----- From: John Barnwell To: sherlinex~xxyahoogroups.com Date: Tuesday, November 27, 2001 8:31 PM Subject: RE: [sherline] Milling Problem >Got a hammer and chisel? >After all its only aluminum. >A "Cape chisel" is what you want. >John Barnwell >barnwellx~xxjlsystems.to >Voice: 978-534-4096 >Cell: 978-807-8475 >> Original Message----- >> From: doug.kelleyx~xxalaskaair.com [mailto:doug.kelleyx~xxalaskaair.com] >> Sent: Tuesday, November 27, 2001 7:13 PM >> To: sherlinex~xxyahoogroups.com >> Subject: [sherline] Milling Problem >> I just purchased a Sherline mill and I'm contemplating my first >> project. I was thinking a Soma puzzle would be simple enough for >> someone with no previous experience. If you aren't familiar with the >> puzzle, it's a 3 x 3 x 3 cube. The cube itself is made up of 27 >> smaller cubes, grouped in various configurations. The puzzle (which >> isn't very difficult to solve) is to arrange the groups of smaller >> cubes to make the larger cube. Various other shapes can also be made. >> >> I want to make the 27 smaller cubes from 1" x 1" x 1" brass. I also >> want to have an aluminum base that the cube can rest in. The base >> would be 3.5" x 3.5" x 0.5" with a .25" deep recess milled into the >> plate to accept the brass cube. If this isn't clear, maybe the >> following ASCII art will explain it: >> >> __ __ >> | |__________________| | >> |________________________| Side view >> >> >> ________________________ >> | | >> | ____________________ | >> | | | | >> | | | | >> | | | | Top view >> | | | | >> | | | | >> | | | | >> | | | | >> | | | | >> | |__________________| | >> | | >> |________________________| >> >> Use a font like Courier to view the above diagram properly. >> >> Here's my problem: I need the corners to be square but if I mill out >> the center of the plate, I'll have round corners. I want the base to >> be made from a solid aluminum plate. I know I've seen square "holes" >> before; how are they made? Or is this topic too advanced for someone >> with no experience? >> Thanks for any input you may have. Please respond directly to me. Doug Hi John: There's 3 ways to do this: 1) mill with the tiniest cutters you can and chisel, broach or file the rest. 2) insert the ends. ( make an "H" shaped pocket and pound in 2 plugs on the ends) 3) EDM the pocket. Your choice will be dictated by the space available, the accuracy required, and the gear you have. Option #2 is the most accurate for HSM's, but requires the most space. Option #1 is what most people typically do (or try to do) Making and aligning the corner broach is the hardest part of method #1 Cheers Marcus ------- Date: Wed, 28 Nov 2001 11:23:51 -0500 From: "Kevin P. Martin" Subject: RE: Milling Problem Marcus wrote: >Hi John: There's 3 ways to do this: 4) Use a v-tipped cutter and an angled head position so the tip of the cutter can reach right into the lower corner. The math is ugly (and easy to get wrong), the setup is a pain, and you get inefficient cutting at the tip of a V cutter because there is so little linear speed. Kevin Martin ------- Date: Wed, 28 Nov 2001 20:41:27 -0000 From: paul_probusx~xxyahoo.com Subject: Re: Milling Problem (See Ty's message below) The same could be done with a very small endmill (1/16" or smaller if you like) instead. Use the small endmill to make the last few fine cuts to remove the large radius from the larger endmill(s) (and bring the cutout to its final dimension)[Note: As you get within a 1/4" of your final dimensions you might consider using progressively smaller diameter endmills until the final endmill is the 1/16" (or smaller) endmill.] Then take that small endmill and carefully plunge cut out the small radius on each corner just enough so that the remaing small radius will not interfere with the blocks. It may not look exactly right since you will not have a sharp corner, but it is quicker and easier than some of the other methods suggested. If the idea is to impress other people, they probably will not notice that small "defect" at all. If the idea is to impress yourself, then use one of the other suggestions. Of course, nothing says that you can't make it with a small "defect" now and when you get more proficient at machining, make another one later. That's one of the problems with HSM's, we're always improving our techniques and going back to improve some of our previous projects. :*) Paul --- In sherlinex~xxy..., Ty Hoeffer wrote: > Or ( Possibly non-elegant but simple ) drill a small hole at the > corner ( its center being at the point that the corner should be. ) a > 1/16" or 1/8" drill would work depending on what size end mills you have: > > WARNING ** CRUDE ASCII GFX FOLLOWS ** > > o--------------------------o > | | > | | > | | > | | > | | > | | > | | > | | > | | > | | > | | > | | > o--------------------------o > > Ty ------- Date: Wed, 28 Nov 2001 21:10:09 -0000 From: jkiefferx~xxmge.com Subject: Re: Milling Problem Doug, one way of doing this would be to machine the square all the way through the material so it would look like a picture frame. Then file the corners square and press fit or recess and mount a bottom plate with screws. Jerry Kieffer ------- Date: Wed, 28 Nov 2001 21:31:11 -0800 From: "Marcus & Eva" Subject: Re: Milling Problem Hi Kevin: Good call. I forgot that one!! We used to pick out corners with that method by scribbling all over the milled sidewalls with a felt pen and then picking up the cutter position by advancing in small increments until we just touched. Zero the handwheels and away you go. Cheers Marcus ------- Date: Fri, 30 Nov 2001 15:31:14 -0000 From: "David" Subject: Re: Milling Problem When using the chisel method you might want to clamp two pieces of angle iron onto the top of the work-piece flush and parallel with the edges forming a corner above the corner you are going to cut. Use at least two clamps on each angle iron to prevent them pivoting. I have used a square lathe tool bit as a chisel for this job. Just grind a relief on the end. Hold the chisel in the corner formed by the angle irons with your fingers or attach a magnet such as a dial base to the outside of angle irons to hold the chisel hands free. The bit will fall onto the work with the hands free mathod so you should put down some paper to protect the work surface. Just light taps will do in aluminum checking visually for clamp slippage after each tap. It's still easy to mess up with a chisel so it's best to practice first. David ------- Date: Thu, 6 Dec 2001 09:12:04 -0800 From: "Marcus & Eva" Subject: Re: DRO From: "Bad Brad" To: Sent: Thursday, December 06, 2001 7:09 AM > Just starting out, > Give dial reading a go first. For the beginner the benifit of learned > dial use improves your skills. Purchase a digital caliper to do quick > calculations for cuts, a more accurate way than using a DRO mounted > on the lathe or mill and cheaper too. Forrest Yes: And do a layout on the job first. Doesn't need to be all that accurate but it keeps you from having to count turns. Use a felt pen for layout fluid, and a cheap vernier caliper with the jaws ground to a sharp tip as a layout gauge. (Unless you've got a surface plate and height gage). Layouts will save your bacon...frequently!!! Cheers Marcus ------- Date: Sun, 16 Dec 2001 19:26:45 -0500 From: "Paul & Charlene Wilson" Subject: Help needed! I need some help from experienced machinists .... I am working on a very intricate piece for my son that involves a lot of complex curves cut with a very small milling cutter - I can do all the setups, cuts, etc. but have run into a problem with actually DOING it. I have made almost the first of about 27 cuts and have already broken both ends of a new 1/16" cutter. Any ideas for getting this done? I am running a fairly high speed - 1000 rpm or so, flooding the cut with aluminum cutting fluid, cutting at low speed (by hand on my rotary table) and still breaking the cutter! Ideas? I just ordered another 5 cutters, but at this rate, it won't be enough! HELLP! Thanks Paul ------- Date: Sun, 16 Dec 2001 18:33:48 -0600 From: Jim Irwin Subject: Re: Help needed! Your 1000rpm spindle speed is way too low. I'd guess even 10,000rpm might be still low for a 1/16 dia cutter with flood or mist coolant. Can't you use a larger diameter cutter? Also, what aluminum alloy are you using? It does matter! Low machineability stuff gets gummy and causes heck in machining. Best regards, Jim Irwin ------- Date: Sun, 16 Dec 2001 19:38:48 -0800 From: Steven Harris <79ramchargerx~xxhome.com> Subject: Re: Help needed! From the back of my J&L Industries catalog it says for aluminum/aluminum alloys using solid carbide end mills the speed should be 600 - 1200 (sfm) and the feed per tooth should be .0002" - .0020". It also says if you are doing slotting applications speed should be reduced approximately 20% of lowest range value and above recommendations are to be used when axial depth of cut does not exceed 1.5 times the cutter diameter. When using long and extra-long end mills reduce feed per tooth 50%. I have not done much mill work. I hope this info helps. Merry Christmas, Steve ------- Date: Sun, 16 Dec 2001 22:55:13 -0600 From: Jim Irwin Subject: Re: Help needed! Steven Harris wrote: >From the back of my J&L Industries catalog it says for aluminum/aluminum >alloys using solid carbide end mills the speed should be 600 - 1200 (sfm) This gives about 36,000 rpm better have a really high precision spindle! >and the feed per tooth should be .0002" - .0020". This gives (2-flute cutter assumed) about 14.4 in per minute at slowest feed rate 144 at fastest! WOW! >It also says if you are doing slotting applications speed should be reduced approximately 20% of lowest range value and above recommendations are to be used when axial depth of cut does not exceed 1.5 times the cutter diameter. When using long and extra-long end mills reduce feed per tooth 50%. Reduce by all these factors and you get a feed rate of 5.76 in/min IOW...no matter how fast your spindle is going, it ain't fast enough! Best regards, Jim Irwin ------- Date: Mon, 17 Dec 2001 09:12:43 -0500 From: mark usik Subject: Re: Help needed! Make sure that you are conventional milling (cutter is trying to keep itself from advancing into the work) as opposed to climb milling (cutter tries to climb or self feed). Any backlash in your setup will allow the cutter to take too big of a "bite" during climb milling ....and we know the rest of the story. Climb milling is used on large , very rigid machines with "zero backlash" to give a better finish over conventional milled surfaces. ------- Date: Mon, 17 Dec 2001 09:34:57 -0800 From: "Bob May" Subject: Re: Help needed! The speed is way too slow. Run the machine up as fast as it will go and go extremely slow (make a bump on the wheel and you'll break a cutter!) If you're used to a 3/8" cutter as a normal sized cutter, you'll find that the speed needs to be at least 6 times faster and the feed rate to be 6 times slower. You also don't want to be cutting that deep a hole with such a cutter. Even slower is better with such cutters. I used to do mold work on a pantograph mill and that is all handwork for moving the cutter about and doing something like a 1" long cut was an exercise in patience! Bob May http://nav.to/bobmay NEW! http://bobmay.astronomy.net ------- Date: Mon, 17 Dec 2001 09:52:37 -0800 From: Frank Evan Perdicaro Subject: Help needed? SHHH! Don't tell anybody, especially any real machinists, but for problems like this that do not involve very important work, I use a wood router and a carbide bit. A wood router spins fast enough. If you can clamp it over your rotary table, prentend you have a milling machine. You can even freehand mill slots. I've done up to 5/8" slots 1/4" wide in a single pass by hand. ------- Date: Wed, 19 Dec 2001 20:22:32 -0500 From: "Paul & Charlene Wilson" Subject: Success, so far Thanks to all who sent suggestions on my intricate curves milling problem with a 1/16" mill; I got a new cutter today (actually several; no faith!) and after setting the mill to max RPM (3100 or so) I have made 4 cuts (out of 40 or so) with no breakage. So far so good ... lessons: - Max RPM - Feed SLOW! - Flood the cut with Aluminum Tap Magic - Keep chips cleared (same brush that applies cutting fluid) It's a mess, and slow, but getting there! Probably not this year, but soon >)! Paul ------- Date: Sun, 16 Jun 2002 13:55:40 -0500 (CDT) From: Tom Benedict Subject: Re: Speeds & Feeds for soft metals On Sun, 16 Jun 2002, jimbarb02760 wrote: > I will be milling(CNC) small highly detailed models made of pure tin. > Cutters will be from .010 flat conical to .250 two flute. I haven't > been able to find information on optimal spindle speeds and feed rates > for soft metals. Any help would be appreciated. Funky! My initial response was going to be, "Consult Machinery's Handbook, page..." So I went to look up the page. And I'll be danged if I can find it! You're right. All of the light metals they list are aluminum alloys, magnesium, and die castable aluminum alloys. No tin. Some things to keep in mind regarding speeds and feeds: What Machinery's Handbook calls "optimal" is "this is as fast as you can cut without destroying your cutter in seconds". They spell this out pretty clearly in the opening pages of the chapter on machining operations. Running at a slower speed means your tooling lasts longer. So a production shop strikes a balance between tool life and machining speed. If you spend all your time changing worn tools, you're losing. But if you're using a feed rate of 1"/minute, you're also losing. So you strike a balance. Unless you're making a massive production run, chances are you can run your tools at a slower spindle speed, and adjust your feed rate accordingly. Looking at the table of recommended feed in inches per tooth for milling with high speed steel cutters, the fasted feed rates (for cast aluminum alloys and magnesium alloys) is 0.003" per tooth. Most of the steels are around 0.001" per tooth. Take that as a ballpark range. I've never cut pure tin, but I'd opt toward the heavier end of the scale. If you take your spindle speed, and the number of flutes on your cutter, you can calculate a feed rate based off of those parameters. Past that, I'd see what works. Try different spindle speeds and associated feed rates, and see what kind of surface finish you get. You said they're highly detailed models. My guess is you'd be after good surface finish more than massive cutting speeds. Take a cutter and some scrap tin, run through the spindle speeds available to you and calculate your feed rates. Look at the resulting surface under a magnifier, and see what you think is acceptable. Pick that one, and cut tin. Sorry I couldn't be of more help. Like you said, that data's not easy to find! Tom ------- Date: Sun, 16 Jun 2002 23:47:17 -0400 From: Stan Stocker Subject: Re: Speeds & Feeds for soft metals Goofy as it sounds, whipping cream or half and half are about the best cutting lubes for copper. A pain to clean up after, but you do get an excellent cut. Stan ------- Date: Thu, 20 Jun 2002 08:56:51 +0100 From: Tony Jeffree Subject: Re: Depth Stop collars on milling bits >Is there anything wrong (dangerous) with putting aluminium collars with >setscrews onto end mills so as to limit the depth they are inserted the >collets? Can't see why this would be a problem, as long as there is no possibility of the collar coming loose during milling. If you used a split clamp type of collar rather than setscrew, there would be less chance of it coming loose. Regards, Tony ------- Date: Mon, 24 Jun 2002 08:49:42 -0500 From: Bob Kelly Subject: Re: Carving Semi-Precious Gems On 23-Jun-02, rrhewson wrote: > I tried carving a small piece of jade using diamond tips with my > Dremel. It works, but sure was slow. Jade is a lot harder than I thought. > Good magazine to reference is Lapidairy Journal (Boreds, Barnes & > Nobel, Chapters etc shold carry it. Bob > --- In taigtoolsx~xxy..., "rainnea" wrote: >> Seeing as we're discussing glass-cutting I was wondering if it > would be possible to carve a pattern into gemstones with for example a >> diamond tipped dental bur. Has anyone tried this sort of thing? Rab Bob, the difference between a Dremel and a dental drill is amazing. I got a brand new air drill when new rules about autoclaving (sterilizing) came out and a dentist had to scrap a new one. That was probably 15 years ago. I think it runs over 150,000 rpm and really eats stone. I am thinking of making a mount for it on the taig so I can hand crank the lathe and let the drill do the work. About the only thing the drill doesn't like is aluminum. It clogs whatever bit I try. Bob Kelly ------- Date: Thu, 7 Nov 2002 13:04:36 -0500 From: "j.guenther" Subject: RE: Advice on milling material larger than machine capacity > I am considering purchasing a Taig CNC Mill and was wondering if it > is possible/practical to work on material that is 6.5"(L) by > 6.5"(W). The Y axis on the machine I am considering has a maximum > travel of 5.5" and I will need to cut slots in the piece that go all > the way to both ends. > I imagine I could probably make half the cuts then move the > workpiece over some and make the rest of the cuts, however, I'm > concerned about how easily and accurately this can be accomplished. > Has anyone done this, and if so, is it worth the hassle or should I > look for a larger capacity machine. I will be producing a fair > number of the same part so if it is significant trouble getting > everything to line up properly I would probably look for a larger > machine. On the other hand, if it is relatively easy to make the > adjustment and get the machine lined up correctly, I think I would > go with the Taig. Any help would be greatly appreciated, Wally I had a similar problem when milling the 4.5 x 14 inch front panel for my CNC driver box. What I did was to make an "L" shaped alignment guide (sort of a jig) to align the panel along the X and Y axis. This allowed me to machine 1/2 of the panel and then flip it over to machine the other half. I made only one front panel and one back panel but I could have easily made as many as I wanted. This "L" shaped alignment jig was just two pieces of aluminum bar bolted to the tooling plate on my Sherline mill table and the inside surfaces aligned to the X and Y axis. This could be done with a DTI or you could take a light cut on the inside faces of the L to square them up to each axis. I wrote the code to cut the panel such that there was a program for the right half of the panel and one for the left half of the panel. I cut one half, flipped it over and cut the other half. When complete the panel looks as though it was cut in one setting. The panel contains 4 2" diameter holes for cooling fans, a hole for a standard printer connector, holes for 4 connectors for the stepper motors, 3 switches and 30 holes for screws to mount the fans, connectors and some internal brackets. I can provide a picture of the completed front panel if needed. HTH. John Guenther 'Ye Olde Pen Maker' Sterling, Virginia ------- Date: Fri, 07 Feb 2003 17:03:16 -0000 From: "cobbkev " Subject: Setup for subsequent holes I have what you might consider a VERY basic newbie question: I am adding multiple holes to a plate that require multiple passes. First center drill then through drill and finally a counter bore and maybe a slight chamfer at the rims (eight total). Do I center drill all the holes first (noting handwheel revolutions and direction) and then change to drill and then through drill all (matching handwheels and direction), etc? Or is it better to center drill, switch to drill, then counter bore etc. before going to the next hole? I've tried MUCH reading before making too many first newbie chips but I don't see this anywhere. Most books usually say "after all your holes are finished, do the following"... Am I making this too complicated? Thanks a bunch! Kevin ------- Date: Fri, 7 Feb 2003 12:21:58 -0500 From: "Ned Carey" Subject: Re: Setup for subsequent holes >Do I center drill all the holes first noting handwheel revolutions. Kevin Which is more of a pain in the the ass to you, changing bits or turning the handwheel and counting revolutions? I don't think it really makes a difference as long as you remember your backlash and count correctly. Ned ------- Date: Fri, 7 Feb 2003 19:20:30 -0800 From: "Carol & Jerry Jankura" Subject: RE: Setup for subsequent holes Hi, Kevin: I'd suggest that you drill all of the center holes, then go back with the drill to complete the job. You'll have to be careful - 1. Set the Zero for both the X and Y axes after you've moved to the edge of the material from a direction which moves the table towards the spindle center. 2. Approach all holes from the same direction. IOW, start with the table to the right of the spindle and moved all the ways into the Z axis column. 3. Always approach a new Y by moving the table away from the column. 4. Always approach a new X by moving the table to the left. Don't 'zig-zag' left and right. 5. When returning X or Y to the 'zero' location, always overshoot and approach your zero from the same side. -- Jerry ------- Date: Fri, 7 Feb 2003 20:58:11 -0800 From: "Marcus & Eva" Subject: Re: Setup for subsequent holes Hi Ned and others: Once you've established the locations with the first tool (or even with a layout), there's no need to count revolutions anymore. All you need to remember is what the dial reading was at each location, and which way the backlash was when you approached the location the first time. You can use the divot in the job that you made with the first tool to eyeball within one dial revolution and then just go to the handwheel setting you memorized (or wrote down). I run a Bridgeport daily, and I've NEVER counted handwheel revolutions in my life. (No, I don't have a readout on the machine) I scribble on some magic marker and scratch a layout onto the workpiece, often just with a beater vernier caliper that I keep pointy on the jaws with an India stone. The layout doesn't have to be accurate, it just has to be close enough that you can't misread the position by one handwheel revolution. So, you just run from your reference location to "pretty close" to the layout line, and then dial in the reading you want. This method is as accurate as the table feedscrew is, and it's WAY faster than a readout once you get good at it. So...abandon the painful tedium of handwheel counting...on a Sherline with its fine pitch screw, you'll be counting forever, and you'll never know if you've made a miscount screwup until you measure the locations, and say those words that you can't let your kids hear. Cheers Marcus ------- Date: Wed, 26 Feb 2003 18:50:32 -0800 (PST) From: Pete Brown Subject: Cutting a perfect square inside material Just a puzzler (for me anyway). I don't have need to do this just yet, but I suspect I will. Without file cleanup, is it possible to cut a perfect square or rectangle with 90 degree inside corners on the interior of a flat piece? For example (square holes are marked with "h"). Assume the holes go all the way through the material. Best if viewed with a font like courier. +--------------------------+ | +-----+ +-----+ | 1" | | h | | h | | | +-----+ +-----+ | +--------------------------+ 3" Assume the piece is 1" x 3" and the holes are each 3/4" x 1". Assume thickness of the piece is 1/4" or something like that. Without resorting to a file or cold chisel after the milling, I can't see how to do that on a mill. Any suggestions? Thanks. Pete ------- Date: Wed, 26 Feb 2003 19:10:45 -0800 From: Alan Marconett KM6VV Subject: Re: Cutting a perfect square inside material Pete, you have to use SQUARE endmills! ;>) Alan KM6VV ps Not to my knowledge! I think you'd have to use a broach. Mill out as much as you can, then press a broach through the holes. ------- Date: Wed, 26 Feb 2003 22:42:09 EST From: tadici283x~xxcs.com Subject: Re: Cutting a perfect square inside material Hey I got a laugh out of that, but to answer your question No, you cannot get a perfect square from a round endmill based on the equipment mentioned, you can use a small diameter endmill to get a very square hole, but it will in the corners still be rounded, so how can you do it? One way is to broach it, like a keyway in a collar; another way is to mill it in two parts and screw, weld, glue it together, by machining it in two parts with the endmill cutting to the side of the square and not form the top. Why do you need it perfect anyway? Almost any project can be done with a nearly square hole that is tightly machined. Note there are other ways to make square holes such a punching it out, but I did not mention it due to the fact that this doesn't pertain to Sherline equipment and the equipment is expensive and specialized. Chris of Bradenton FLA. ------- Date: Thu, 27 Feb 2003 04:18:42 -0000 From: "Les_Grenz " Subject: Re: Cutting a perfect square inside material It could be done with a shaper. However, a shaper is not always available. Regards, Les http://www.lesgrenz.homestead.com/Leshomepage.html ------- Date: Wed, 26 Feb 2003 20:24:02 -0800 From: Brian Pitt Subject: Re: Cutting a perfect square inside material I had to do something like that once on a knee mill and one of the 'old boys' walked me thru it you use a cutter with a 60deg point like a center drill with the pilot ground down to the center flutes and thin the web so it is as pointy as possible tip the head 45deg to the side and 45deg back (or forward) then raise the knee to make the cut down the inside corner on the sherline you don't have the knee but you can tilt the head on the Z-axis and mount the work at an angle on the table to get the same kind of thing going on with maybe some adjustments to the angles (the trig part of my brain is broken right now :) the cone of the cutter should be 90deg looking straight down on it to make a square inside corner make a big 60deg paper cone and hold it at the right angles to fit into the corner of a room or doorway and you can get a good idea how it works Brian ------- Date: Thu, 27 Feb 2003 14:35:04 -0000 From: "lan_brooks " Subject: Re: Cutting a perfect square inside material Another, much more complex solution is to get the Home Shop Machinest book on building an Electronic Discharge Machine, build the EDM and using a square/rectangular electrode erode the hole. Actually, I am faced with a similar situation where the hole I need is 3/32" by 1/4 " but 1" deep and a need two holes per part and about a dozen parts. Broaching is one solution, EDM another and I hadn't thought about making the part in two pieces since it is a prototype and I like real looking prototypes. I started gettign ready to make the EDM but did not have easy access to appropriate parts in the small town where I live at a reasonable price. For your part, many of the ideas others have had sound workable especially the pointed end mill, the real issue is how thick is the part. For a thick part, where the pointed mill will not go all the way through, broaching would work well. You would need to make a bushing that fits the hole, had three chamfered corners sufficient to clear the radius left by the end mill and a square or rectangular notch in the remaining corner that fit the broach. This won't work for my project due to the cross section of the 3/32 standard broack. If you can select the end mill size, you can then select a broach with a square cross section. Good luck, Lan ------- Date: Mon, 10 Mar 2003 21:32:26 -0000 From: "JohnW" Subject: Re: cutting ovals [sherline] kevin_sedota wrote: > > How would you cut a plate in the shape of an oval or ellipse? > > Without CNC. thanks, kjs Alan Marconett KM6VV wrote: > Hi Kevin, > It would be tough! You could generate a set of coordinates using BASIC > or a spread sheet, and then TRY to go to each coordinate in sequence. > Trouble is, you should turn both X and Y handwheels at once to get to > the new coordinate! If the moves were small, perhaps it wouldn't be too > far off, even if only one were turned at a time. I wouldn't be up to it! > The other option is to rig a pantograph (sp?), or tracer somehow. > This is done on lathes, don't know about doing it on a Sherline mill. > Alan KM6VV Kevin: The oval chuck in HSM than Glen mentioned should do the trick. It was mounted to a rotary table to get the circular motion. The chuck works on the same principle as the "do nothing crank". I'll try to describe how the crank works, but don't ask for a picture or drawing ;-( A block of wood has tracks cut at right anges to each other and crossing in the middle. The crank has two small rectanglular pieces of wood attached that ride in these two tracks. When you turn the crank each sliding block moves back and forth in its respective track. The handle travels in an oval. The difference between the major and minor diameters of the oval depend upon how far apart the two sliding blocks are mounted on the crank. I'm sure you've seen one and I hope that my description was good enough for you to guess what I'm talking about. John ------- Date: Wed, 16 Apr 2003 07:00:31 -0000 From: "sikn1gh7" Subject: Re: Drip Oiler for Cutting Steel on Mill? Pick up a separatory funnel from your local science surplus store. You can tune the teflon stop-cork for some pretty nice drip rates. If I were to home-brew a drip coolant system, that's the route I'd go. http://www.sciplus.com/category.cfm?subsection=4 Terence ------- Date: Wed, 16 Apr 2003 13:48:16 -0000 From: "JohnW" Subject: Re: Drip Oiler for Cutting Steel on Mill? Mug a hospital patient and take his IV drip. ;-) Or copy the concept. Use a small valve or an adjustable pinch clamp to control the drip rate. Copper tubing is easy to bend and can be used to direct the drips where you want them. Haven't done it yet but that's my design. John ------- Date: Wed, 24 Sep 2003 09:51:19 -0700 From: "Marcus" Subject: Re: Working outside of Sherline's milling envelope [NOTE TO FILE: sherline group posting but of interest to other machines] > I'm a couple of weeks away from my first major project using a CNC'd > Sherline 2000 mill. I'd like to see if I'm on track so that I don't > scrape some relatively expensive material (aluminium tooling plate). > The piece is to be an 18" X 5.5" slide milled from 3/4" stock. It > requires a dovetail, straight within 0.001", and 10 threaded holes to > be machined into it. How committed are you to completing this job in-house?? It sounds like your requirements can only be met if you are willing to spend a lot of time fussing over your setup. An 18" slide milled to within 0.001" is a reasonably difficult challenge even on a machine that has the stroke. Just the warpage of the block is likely to throw you out of tolerance, nevermind the errors introduced by the progressive warming of your entire setup as the cuts progress. If you are certain you can get there by milling and scraping, then you may choose to do it in spite of the time penalty, but you can be certain it'll be a long process if you REALLY have to get within 0.001" over 18". I'm assuming the job will be aluminum? If you get a nice hard grade like 7075 or Alumec 89, you can surface grind it successfully. I'd mill this job on a reasonable sized mill and then plan to grind it to final dimensions. Good luck with it, however you choose to go. If you do choose to mill it, you'll want to let it stabilize after you hog out the worst of the stock. I'd rough mill it within 0.030" and stick it in the freezer for a week. Then I'd semifinish to within 0.005" and freeze it again. Last I'd kiss it with brand new cutters freeze it one last time, and then scrape it in. The subzero ageing is supposed to accelerate the stress relieving process. Shot peening is supposed to help too. Remember to remove stock from both sides of the block, otherwise the asymmetric stresses will make it curl. I know tooling plate is not supposed to do that, but in my experience it often does anyway. Cheers Marcus ------- Date: Thu, 25 Sep 2003 14:19:16 -0000 From: "Antonius J.M. Groothuizen" Subject: Re: Working outside of Sherline's milling envelope Marcus: Thanks for your insight. I am committed to completing this in-house as it is personal, and I can't afford to farm it out. I blew my wad buying the equipment. I can afford to take my time to do this right and will test some of my procedures using PVC and smaller pieces of cheap aluminum from the scrapyard. I set the tight tolerance for myself as this is the first step in expanding the milling envelope on my Sherline 2000. The accuracy of future projects depends on this one. I was considering precipitation strengthening (aging) the 7075 by putting it in the oven at 250 F for 24 hours and air cooling it after hogging out the material, and once again after final machining. (I do the cooking around here, so it's my oven ;-) From your comments it would seem that I'd be better off putting it in the deep freeze. Would a semi-controlled return to room temperature (fridge freezer, fridge, room) offer any advantage? I'll hog the material out starting with a 'W' profile, alternating sides from the center, and allowing cool-down time between cuts to minimize curling. Tony ------- Date: Thu, 25 Sep 2003 08:41:14 -0700 From: "Marcus and Eva" Subject: Re: Re: Working outside of Sherline's milling envelope Hi Tony: The information I have on subzero ageing is all hearsay, so I can't comment definitively on its value. Certainly any process that accelerates stress release will help you and temperature swings will do so. Once upon a time castings were aged by leaving them out in the yard for a decade. They were also hung up and thumped with rawhide hammers. As I mentioned previously, shot peening has been used as well. The short version is that anything you can think of to accelerate the stress release process will help you. With regard to the actual machining operation, you want to minimise stresses from clamping and realigning. Get yourself some thin shim stock or a couple of packs of feeler gages. You'll want to have a clock on the part at all times as you tighten the clamps down...that way you can tell immediately if you're pulling it out of alignment with the clamp. I've laid parts like these on double sided tape and then just blocked them into position, so they can't shift sideways. With light cuts, this is a very successful way of avoiding the twisting forces of clamps. The main thing is be gentle as you set up the parts when you're finishing them. There'll be a whole lot less scraping to fit if you do. Cheers Marcus ------- Date: Thu, 25 Sep 2003 16:47:13 -0000 From: "Charles Hixon" Subject: Re: Working outside of Sherline's milling envelope Marcus, Good call with "subzero ageing". Since temperature does change dimensions ever so slightly, it will allow a non-measurable amount of crystalline slippage where internal micro stresses are the greatest. One "subzero age" cycle in aluminum might be equivalent to one thump with a rawhide hammer. With reference to aluminum, and metals in general, ageing typically means hardening by inducing internal stresses through the precipitation of compounds into a crystalline lattice structure. Hardness dervied by inducing internal stresses warps the metal. This is the opposite of dimensional stability. Better terms which may be used to define enhancing dimensional stability might be annealing, normalizing, tempering, stress- relieving, or softening. An exception you brought up is "aging" of castings, which was done to cull out those castings which would crack for mysterious reasons. The mystery is gone now through our understanding of metallurgy and the application of heat treatment. There is a "subzero" treatment applied to certain hardened steels but that's another topic. Shot peening introduces residual stresses and hardness to the surface by virtue of cold working - if the material grade responds to work hardening. If it doesn't, then shot peening only roughens and possibly warps the surface. Either way shot peening creates a dimensional stability problem. Charles Hixon ------- Date: Mon, 17 Nov 2003 08:27:18 -1000 (HST) From: Tom Benedict Subject: Re: Turning on Mill [POSTED TO TAIGTOOLS GROUP] On Mon, 17 Nov 2003, Robert MacLellan wrote: > Thanks all for their responses to my really simple question posted > earlier. Am now starting to think the Micro Mill might be a better way > to go. Will likely be seeing a 70/30 milling/turning environment. So, > is it possible/advisable to turn using the Mill? Yes it is, but there are some caveats. For starters the mill spindle motor is a lot weaker than the one used on the lathe. If you're turning large stuff, you'll either want to replace the mill spindle motor with something a little beefier, or you'll want an honest to goodness lathe. Changing setups takes time. What that means is it's a pain to go from lathe to mill to lathe. Any time my hobbies get to be a pain, I lose interest in the hobby. If you're looking at a 90/10 milling/turning environment, I'd say go for it with few or no hesitations. If you're talking about a 70/30, still consider picking up a lathe. Something to think about: The Taig lathe and mill both use the same spindle. The accessories that go on the one will go on the other. My lathe cost me less than two hundred bucks. My lathe accessories easily cost me twice that. When I got my mill it meant I didn't have to get a lot of extra tooling for it because I already had it for my lathe. The reverse would've been true if I'd bought the mill first. If you're going to be tooling up with a mill, consider picking up a bare-bones lathe along with it. > Either by: 1. mounting chuck on mill head (after all is same unit > as lathe) and tool on mill bed? Yep. This is how I've done some face milling on my mill. At one point there were some pictures in the Files area showing my mill set up as a lathe. I asked Nick to erase them because they were photos and not files, and were eating up too much space. As soon as I can get around to it, I'll duplicate the setup and take more pictures to post in the Photos area. Mounting the chuck this way is dead easy. It just screws onto the spindle, same as on the lathe. Mounting the lathe tools is a little tougher. With the mill spindle mounted vertically, you can bolt all the lathe tools to the mill table with the pointy ends facing up. But it means lowering the mill spindle WAY down. With the mill spindle pointed horizontally you need the tools mounted pretty high up to get decent throw. I've been cobbling setups for both configurations, but your best bet would be to treat it like an honest to goodness shop project and make a lathe tool holding fixture for your mill table. The way I'm doing it right now is juuuust frustrating enough that it takes some convincing to make me set my mill up as a lathe. If I had a dedicated fixture I'd be a lot more likely to do it. > 2. Using vertically mounted rotary table/chuck and maybe tail stock? I haven't done this, but I did make an adapter plate so my lathe can mount on the mill table. That lets me do lathe work with two live spindles, or pull the headstock off the mill and replace it with conventional lathe tooling. I'm going to be using this setup pretty heavily in the next couple of weeks, so I'll take pictures and report on how it works. > Anyone had any experience doing this? Some. But no, not enough. Never enough. ;) Tom ------- NOTE TO FILE: This thread was how to mill large areas in a Taig lathe, with the suggestion that hogging out most of the metal with a drill bit first was the best way to proceed. Then someone started talking about using mill bits in a drill press, and Clive contributed the following message. To see the rest of the thread go to the file Taig Lathe Tips. It is generally accepted that MILLING ON A DRILL PRESS IS UNSAFE AND IT IS NOT RECOMMENDED. ------- Date: Tue, 2 Dec 2003 15:05:36 +0000 From: Clive Foster Subject: Re: Milling large volumes Gents, I can confirm that attempting to use an end-mill in a normal drill press will cause the chuck to walk out if it is on a separate morse taper arbor. The chuck wont walk off a good jacobs taper so if its a press fit on the end of the spindle you will almost certainly be OK providing the tapers are somewhere near accurate. Unfortunately the end mill will probably walk out of the chuck! The spiral side flutes put a decent pulling force on the mill which the hard steel on hard steel grip of the chuck jaws just wont withstand for long. Light end milling on drill presses is possible. Some makes were specifically made with that capability eg Fobco but the bearings etc are a cut above the usual. However you can upgrade, within reason, even a cheapy for light milling. Do it somewhat like this:- To start with it is best to pick one with a morse taper arbor and a proper spline drive from the pulley. A single slot key-way drive can be used but you ill almost certainly have to make a snug fitting, full depth key properly retained in the drive pulley. Hard work if you don't have machine shop access 'cos its gotta be accurate. Make the end-mill holders from blank end morse taper arbours, one for each size of milling cutter shank. Plain holes with a side set-screw engaging in a flat on the cutter shank will do fine (its what is used for the throw-away cutters after all) but if you are feeling swanky thread them as well for screw in cutters. You can buy suitable morse taper holders but they are threaded for a draw-bar so you need add a tang substitute so that the ejector drift has something to work on. A hollow cap nut passing over the business end and screwing onto the spindle will stop the end-mill holder walking out. Depending on sizes you may want to weld on a washer to the big end of the morse taper to give the cap nut more to register on. Obviously the hole in the cap nut must pass all sizes of end mill holder. You need a better down-feed. Basic principle is a substantial bracket on the bottom of the quill with some sort of screw thread arrangement to push things down. Time to get creative I'm afraid but its probably best to have a coarse adjustment slide movement which can be locked so the screw thread is only used for fine adjustments. Include suitable reference faces so you can use your digital calliper as a down feed measurement device. Fit a good solid quill lock clamp. Squeeze is probably better than screw in but really the drill layout determines what you can do. What you do to upgrade the bearings is again dependent upon how the drill is designed. Perfection is the ball thrust, needle roller side bearing units made by SKF and others but a pair of those will prolly cost about twice as much as the drill did! If you are lucky simple substitution of good quality bearings for the originals will do the deed. I think the best method is to use a pair of taper roller bearings but these will cost you a bit of quill movement as the relatively large diamete