This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------ Here find lots of user tips on boring holes in metal using metal lathes and milling machines. Boring a hole in metal is a particular machining procedure that may be accompanied by other related operations. Before beginning this web site, I was already gathering information on subjects like "Drilling Tips" and "Boring" and "Reaming" and "Lapping". They once had separate files on my computer, and originally had their own separate files here. It has become painfully obvious that while lapping is a very useful process, you folks rarely talk about it. And when you do talk about it, you often throw some lapping info into a thread that started as boring or reaming, etc. Consequently the messages from the separate "Lapping" and "Reaming" files have been combined into the "Lapping and Reaming" file. There is still some other lapping and/or reaming info mixed in with the Boring or Drilling Tips messages. Consequently, you should really read the last three files to find good solutions that may involve multiple processes. The "Finish and Polish" file may also be useful for your particular need, as lapping is related to some polishing techniques. Let's just clarify a few terms so that we are all on track here. These are my very simple definitions. "Drilling" most commonly is the act of using a drill bit to make a "round" hole of a specific diameter. The resulting hole is often rough, and rarely of the same diameter as the drill bit, and often not even round, and can end up quite crooked in direction from the path intended. "Boring" is the act of using a boring tool to widen an existing (drilled) hole to a larger diameter. By slowly increasing the diameter of the boring tool's cutting arc in several stages (so as not to bend the tool sideways), the resultant hole is round, and straight (even if the original drill bit had wandered), and fairly smooth. "Reaming" is the act of passing a precision reaming cutter through an existing hole; the reamer is only a small amount larger in diameter than the existing hole. The reamer brings the hole to a perfectly round shape and size appropriate to the size of the reamer. The walls of the reamed hole will be smoother than a drilled or bored hole. If the original hole was straight, the reamed hole will be too. But a reamer will follow a crooked hole if that is what you started with. "Lapping" (a hole's wall) is the act of passing a lap repeatedly through the hole until the wall is smooth and free from minor defects or tool marks. The lap, usually a metal cylinder, is the perfect matching shape for the inside of the hole and is just smaller enough in diameter to allow for a lapping compound's particles to fit between the lap and the wall. The lap itself must be softer than the hole's wall material so that particles of the lapping compound might bed into the lap, but not into the wall. Depending on the smoothness required, lapping may be done with successively finer grit lapping compounds until the desired result is achieved. Lapping, properly done, does not significantly increase the diameter of the hole. Where the hole is now a very slight "interference fit" (an object to be inserted needs force or heating-of-the-hole-part/ cooling-of-the-insert-part), lapping may change that to a precision sliding fit. Bigger hole-size changes are best done with a reamer or careful boring operation first. If you got to this file directly from my HOME PAGE, return there by using your browser's back button. BUT if you came to this file as the result of a web search engine, see many additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/index.html SAFETY WARNING BEWARE: DO NOT ASSUME that any subject matter or procedure or process is safe or correct or appropriate just because it was mentioned in a news/user group or was included in these files or on this site or on any other web site or was published in a magazine or book or video. 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 - 2015 Machining and Metalworking at Home The form of the collected work in this text file (including editing, additions, and notes) is copyrighted and this file is not to be reproduced by any means, including electronic, without written permission except for strictly personal use. ========================================================================= Date: Wed, 22 Nov 2000 01:03:30 EST From: SLEYKINx~xxaol.com Subject: Re: Re: boring bar head for Atlas 6" - question? Ok .. If the block of steel with a hole drilled in it to hold a boring bar is too much effort or you just want to use the lantern toolpost, you can try what I did once upon a time :) I just took a piec of steel bar stock that fit nicely in the lantern post and drilled a hole to fit the boring bars. I then cut a slot and drilled and tapped through the slot to make a clamp. If you want to get fancy you can bend it to about 45* and be very close to the store bought ones. Of course there are several styles of boring bars and you need to decide what you want to run first ... then it would be nice to run one before you decide to use it ;-) For general purpose make a hole type I prefer the cheap brazed carbide set for about $20 you get a box full of different sized bars all with a 1/2" shank. They are not real heavy duty but they give a nice finish and hold an edge well. For threading and special things in mild steel or less I like the ones with the square hole and set-screw to hold a HSS tool bit ground to the shape for the job. For heavier duty material I would go for the carbide insert style. I have a whole cigar box full of the HSS rods that are bent at 90* and ground to make a boring bar but I still need to find a good use for them :) Bottom line...for a boring bar holder anything you can fix to the compound slide and drill for the size bar you use should work well. The block with a bolt through it is about the next best thing to a QC. You just make a hole to mount it to the compound then chuck a 1/2" drill in the 3 jaw and run it into the drill to make the hole at just the right position. Then you drill and tap for setscrews to hold the bar. I went fancy and cut slots on two other sides to hold a turning/facing tool and a parting tool. I used some shims under the block to raise it to the proper hight for cutting the slots so the other cutters come out right on center. Just chuck up an end mill and cut the slots right on the lathe. Make some chips and Enjoy! Glenn ------- Date: Sun, 18 Feb 2001 10:11:00 -0800 From: "Wm. Dubin" Subject: Boring question I need to bore a large brass cylinder to 1" thru a depth of 3.5". I've not seen a bore tool that is long enough to do this in my catalogues (MSC TRAVERS J&L) except those which use a carbide insert and cost nearly $100.00 once you purchase the inserts. I can, with my present bore tool, make this, if I bore from both ends, and essentially meet in the middle. I have an extra long 1/4" drill bit, that would allow me to drill thru the full length with out reversing the cylinder, however I'm afraid of the drill wandering in so deep a hole. This might not matter, given the final bore width of 1". My plan is to drill the 1/4" hole from both ends, so that I'm relatively sure of getting it centered. Then, change to the 4-jaw, and center the 1/4" hole with the DTI...and then bore to mid-length just under the 1" width. Reverse the cylinder in the 4-jaw, re-center on the 1/4" hole, and bore this side out to as close as possible to the other. I can't use a 1" reamer in my tailstock, so I'm thinking of finishing this by making a split wooden rod with a piece of heavy sandpaper in it, and then hand-sliding the tail stock up & down the bed to work like a lap, until I've reached the size & "smoothness" inside that I need. This bore needs to end up a "loose" sliding fit on a 1" stainless rod, so while I want it to be accurate, it shouldn't be TIGHT... if you follow. Can anyone add any suggestions to this? Or, is there another, better, way? I know there are ways to mount the cylinder on the cross slide and turn a long boring tool between centers, but I've never tried this, nor do I have the long bore tool, and I'm not certain I could get the cylinder mounted EXACTLY on the cross slide. Any help will be appreciated. Wm. ------- Date: Sun, 18 Feb 2001 14:37:55 -0500 From: ron ginger Subject: Re: Boring question If the outside diameter is small enough, mount the work on the lathe table, and run a boring bar between centers. The bar can be made from a simple piece of rod, about 3/8" would work, 1/4" maybe. You put one end in the chuck, the other has a center hole and is supported by the tailstock. In the middle of the rod you drill a cross hole, Id use 1/8" and make a 1/8" dia cutter to stick out the side. Hold the cutter with a set screw. You can buy 1/8" dia HSS tool blanks from most of the usual places. If you try to bore it in 2 sides be very carefull on the centering in the 4 jaw- altough you can get the hole to run true on center, the axis of the hole may be way off making a wobble. You could slip a close fitting 1/4" rod into the hole, and be sure its end points right to the center of the tailstock, as well as running true aolong it length. ron ------- Date: Sun, 18 Feb 2001 16:44:01 -0500 From: "Rich D." Subject: Re: Boring question Wm, Your last idea is the way, and the tool is easy to make. Bore the initial hole about 5/8" dia first by whatever means. Pass the boring bar with the cutter in the center thru holding one end in the spindle chuck and the other to a rotating center in the TS. The work is held to the saddle and moved left/right to bored to size. Yes, it's a bit of trouble to get the final bore to size by adjusting the bit for each cut, but it works well. Tip: the bit hole in the (1/2") bar is at an angle to allow measuring from one side of the bar to the tool tip. 1/2 bar dia minus tool extention times 2 equal bore dia. (assuming no bar runout). I have not seen this style boring bar for sale. Use 1/8" HSS sq tool bit. ------- Date: Sun, 18 Feb 2001 19:03:26 -0800 From: "Marcus & Eva" Subject: Re: Boring question Hi Wm: Just make yourself a decent boring bar out of a 5/8 dia or 3/4 dia ejector pin cutoff. Get one from a moldmaking shop. They cut them off to length from a standard pin and normally throw away the discard. They are nitrided on the outside and are tough. They make great boring bars. Predrill the brass bar with a 1/2" drill and then a 7/8" drill in the drillpress. Clamp the job really well; brass is "grabby" and will tear apart a wimpy setup. It also helps to stone a bit of negative rake on the cutting edges of the drill. After you've poked a hole through the brass, chuck it up in the 4 jaw and mount the fixed steady if you're nervous about the length sticking out from the chuck.(assuming the outside is round.) Bore the hole from one end. If you want, you can lap it to final size as you described. The boring mill method of mounting the job to the cross slide is a royal pain in the rear. It's hard to line everything up properly, and hard to hit the size you want accurately. A 3.5" deep hole 1.0" dia in brass is no sweat at all to do from one end, even on a Sherline. But you need a good bar. It's definitely worth the hour or two that it takes to make one. Make a nice husky holder for the bar while you're at it, and you're set for life. That'll take another couple of hours. Cheers Marcus [NOTE TO FILE: THIS NEXT MESSAGE IS OUT OF DATE ORDER BUT WAS PLACED HERE AS IT CONTAINS A 2005 ELABORATION OF HIS TIPS.] Date: Sun, 2 Jan 2005 14:19:36 -0800 From: "Marcus and Eva" Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! I just had to get in on this thread, with my own kooky ideas on how to bore a hole. As some of you may know, I am not a fan of boring heads for the majority of the work I do. My reason is that the large eccentric mass of the head swinging around in circles makes for poor accuracy, and poor finish. My favourite boring tool for holes over 3/8" diameter and up to about 3/4" diameter is a piece of 3/8" ejector pin cutoff with a 1/8" hole reamed in the end at a 30 degree angle, and a cross hole for a 6:32 setscrew. I use broken 1/8" shank carbide endmills for toolbits, and sharpen them freehand on the bench grinder with a diamond wheel. I set the diameter either by touching off the side of the hole with the toolbit, or by setting a cut increment with a dial indicator. The shank of the tool always runs concentric, and the eccentric mass of the toolbit is very low, so I can run it at high spindle speeds without chasing the machine around the shop. For tiny holes I do have a home-made boring head, but it also uses tiny 1/8" diameter tools and the slide is low mass with a bunch of closely spaced vertical holes to accept the 1/8 shank tools I make up for it. I didn't bother with an adjusting screw at all...I've found they're not that accurate anyway, and they're a pain to try and read. My solution is a simple stop screw and either feeler gauges or gauge blocks to set the cut. With gauge blocks I can reliably set to tenths without any guesswork, and bore my hole at 2000+ RPM. In tiny holes (I mean down to 0.025" or so) the peripheral speed of the tool point is important, and I can't get even remotely near where I have to be with a regular boring head. So I encourage all of you to dump your boring heads in the dumpster (just kidding) and give this option a try. It's been a far better method for me, and I used conventional boring heads for years before I got smart and ditched mine. Cheers Marcus ------- Date: Mon, 19 Feb 2001 02:11:49 -0600 From: Gordon Couger Subject: Re: Re: Boring question Why not just replace the tool post with a block of aluminum and put a 1/2 or 3/4 inch bit in the head stock an drill a hole near one edge of the block and make a boring bar holder and drill a hole in the end of a piece of steel bar to fit the holder and use a drill bit as an insert for the boring bar. Just sharpen the bit like a lathe tool. hold the bit in place with a set screw or braze a piece of carbide to the end of the bar. It is a lot easier than mounting the work on the saddle. Gordon ------- Date: Sun, 10 Jun 2001 13:26:29 -0400 From: "Carol & Jerry Jankura" Subject: RE: Mill tooling Original Message----- From: ron [mailto:ron]On Behalf Of ron ginger Sent: Sunday, June 10, 2001 12:25 PM To: sherlinex~xxyahoogroups.com Carol & Jerry Jankura wrote: > ........... screw the arbor onto the > headstock, drill the opposing end slightly under the required size (This > would use the horizontal boring bar that comes with the Sherline lathe > tool set) and use a reamer to enlarge it to size. >>A minor nit-pick here. Drill the hole first, then bore it with a single point tool to get it round and on center. If you are good with the boring bar you can finish it to size with the boring bar, else run a reamer in to make the final size. A reamer run into a drill hole is likely to be off position and not straight. Boring with a single point bar is the only way to put a hole where yuou want it, and make it round. Rills make triangular lobed holes, and reamer will follow them. ron ginger << Ron: If I understand you ... I can drill a hole "to size." If I do, the hole will most likely be oversize, not round, and not on center. or I can drill a hole, and then ream it to size. If I do, the hole will be round, but will probably not be on center. or I can drill a hole somewhat undersize, and finish it to near size with a boring tool. Then use a reamer to bring the hole to size. If I do, the hole will be on center and of the correct diameter. or If I'm really careful, I can drill the hole somewhat undersize and finish it to the exact size using only a boring tool. Originally, I hadn't thought about being off center using the drill-reamer combination, but used the drill-bore-ream method simply because I didn't want to drill a 15/32 diameter hole with the Sherline tools. I would assume that the drill-bore-ream method is the preferred alternative, right? Carol & Jerry Jankura Strongsville, Ohio ------- From: "Kenneth Ault" Date: Sun Jul 29, 2001 4:15 pm Subject: Stupid question from a beginner I'm trying to teach myself basic machining and need help with a stupid question. I have more or less mastered the art of turning and facing a piece of aluminum and am now working on boring. I am holding a small piece of aluminum in a three jaw chuck and trying to bore out a hole in the center. The problem I am having is that the boring tool tends to screw the work out of the chuck. Even taking VERY light cuts the work moves out of the chuck and screws itself onto the boring bit. I don't think I can get the chuck any tighter without damaging it. It is already digging into the work piece. I have changed the turning speed and the feed speed, but haven't found a combination that works. Is the three jaw chuck just not up to this job or am I doing something seriously stupid? Thanks for your help! Ken Ault ------- From: "Yasmiin Davis" Date: Sun Jul 29, 2001 4:36 pm Subject: RE: [sherline] Stupid question from a beginner I would guess that your feed rate is too fast. You need to feed very slow and you might increase the spindle speed as well. I am assuming that you have the tool at the correct height -- just shy / at the center line. I am also assuming that the tool you are using is one that is commercially made for boring. If you have ground your own you might look at the rake of the tool depending on the tool shape it may be too steep. Also there is plenty of clearance on the back side of the tool. That is it is not touching the other side of the bore. Just a few possibilities -- others will have more. Regards, Yasmiin ------- From: "Dan Statman" Date: Sun Jul 29, 2001 4:29 pm Subject: Re: [sherline] Stupid question from a beginner Ken, is the piece that you are boring very long? Are you using the steady rest to support the non-chucked end? If you are not using the steady rest then the bar is being deflected off center by the pressure of the boring bar and this is causing the piece to come out of the three jaw check. If you are using the steady rest then you may have the steady rest off center from the chuck. If the hole you are boring is concentric with the outside diameter then the part will appear to spin true even if the steady rest is holding it off center. No amount of tightening on the chuck jaws will prevent the part from slipping out if it is not held true to the chuck. It also helps to keep your boring tool as sharp as possible as a dull tool will deflect the part more than a sharp one. Give us some more specifics of your part, and we can help you better. Hope this helps a little. Daniel J. Statman, Statman Designs http://members.rennlist.com/statmandesigns ------- From: "Carol & Jerry Jankura" Date: Sun Jul 29, 2001 5:02 pm Subject: RE: [sherline] Stupid question from a beginner Ken: I, too, am in the learning stage. However, I've been able to bore aluminum, brass, and steel using the Sherling 3" 3 jaw chuck on the lathe. A question - You've already bored a pilot hole into the aluminum, right? Assuming that you have, is there any lubricant on the aluminum or the chuck jaws? That would certainly cause slippage. Other than that, are you certain that the chuck is tightened on the jaw sufficiently? You should use the tommy bars to tighten it; it should be more than "hand tight" Jerry ------- From: "David Goodfellow" Date: Sun Jul 29, 2001 5:04 pm Subject: Re: [sherline] Stupid question from a beginner Hi Ken, I'm no expert, but my experience has been similar to yours with a 3-jaw chuck. When I moved to a 4-jaw, things got better. The one occasion when I clamped the workpiece to a faceplate, it was an "uneventful" session. Uneventful is good. I think maybe tightness is not as much of an issue as is clamped area -- the more clamping surfaces the better. Hope this helps. Dave Goodfellow Northridge, CA ------- From: ballendox~xxy... Date: Sun Jul 29, 2001 5:54 pm Subject: Re: Stupid question from a beginner For the original question, I'd check to see that the tool is properly shaped, EVEN if it was commercially purchased/ground. Many of the "import" grade boring bars I've seen are TERRIBLE... Incorrect angles are the most likely cause of your problems. Second, I disagree with the tool height suggested by Yasmiin. If the tool is set AT or BELOW center, it will dig into the bore when it flexes... Set it just above centerline. Now when it flexes, it will "come out" of the cut. A second advantage of this is that the relief required is slightly less, making the tool stronger. Third, check the rigidity of your setup, INCLUDING the saddle and crosslide gib adjustment. Boring is going to put cantilevered forces on the slides that you prob'ly didn't encounter with your basic turning "lessons". You may need to "tighten" up the slide travels. Hope this helps. Ballendo P.S. There's no such thing as a stupid question, only stupid answers :-) I hope this isn't one of those... ------- From: "Kenneth Ault" Date: Sun Jul 29, 2001 6:05 pm Subject: Re: Stupid question from a beginner Thanks for all the responses - this list is great for beginners!!! I was able to finish my boring - (it wasn't boring at all) by adjusting the height of the boring tool very sightly - after raising it slightly, light cuts no longer "screwed" the work onto the tool. I really appreciate your help and I'm sure I will be back again! Thanks, Ken ------- Date: Fri, 31 Aug 2001 01:14:57 +0000 From: Jon Elson Subject: Re: Re: Why does my 12 X 36 chatter? [NOTE: THERE IS A GREAT DEAL OF DISCUSSION IN THE FILE "Atlas Repair or Fitting" ABOUT METHODS TO REDUCE CHATTER OR VIBRATION IN ANY LATHE.] Dee Schuyler wrote: > All this talk of vibiration and chatter, I was out at a big machine > shop recently and I saw a lathe with a bungee cord around the chuck, > naturally I had to show my ignorance and ask the operator what it > was for, was I suprised when he told me it kept the chatter down, so > I guess anything is possible. on his machine it worked. Guess that > is the bottom line! I will relate one experience where I found a wierd kludge worked well! I was doing a deep boring operation on something, and the biggest bar I had was a 5/8" solid, double-ended boring bar. I was getting some odd vibrations that were building up on each pass. I noticed the vibration was pretty severe on the free end of the boring bar, so it ocurred to me to change the natural frequency of that free end by putting a random cutting tool in that end. It stopped the vibration, and the rest of the boring passes were clean and free of chatter marks. Jon ------- Date: Sun, 9 Sep 2001 09:57:51 -0900 (PDT) From: Larry Meile Subject: Re: boring and honing On Sun, 9 Sep 2001 R10440Px~xxGateway.Net wrote: >I'm using my Atlas 10in to bore out a Homelite 30cc aluminum head to fit a little bigger piston ( going from a 1.430 to a 1.500 piston) but cannot seem to get a real nice finish inside due to the four port cavities that are molded into the head. Also, how would you hone this thing without your hone catching in the four ports? Confused---Rick < Regarding honing. Aren't the stones on your cylinder hone long enough to bridge over the ports? It has been my experience that, other than for a limited position where the ends tick a little as they pass by the cutout portion of the cylinder, the hone acts as if the ports weren't there at all. My cylinder hone has 3" long stones. Larry M. ------- Date: Mon, 10 Sep 2001 02:40:13 -0000 From: "George" Subject: Re: boring and honing You might be setting yourself up for a headache! A lot(most) of the small 2 cycle engines such as weedeater & chainsaw engines have the cylinder hard-chromed and if you bore them out then you have CR02 rings running on alu. and that spells Trouble, the cylinder will wear out verry verry quickly! You could bore it out to say 1.520 and then take it to a full service hydraulic shop and have .030 to .040 hard-chrome put in it and then grind the bore to 1.500 with a toolpost grinder. I don't know how much it would cost you but it would be worth a try! As far as honing goes try lapping it instead of honing -- the lap won't know the ports are there! hope this helps some George ------- Date: Wed, 12 Sep 2001 03:44:51 -0000 From: jtoolman2000x~xxhotmail.com Subject: Re: Boring head on Taig Mill Have a look at the miniature boring head I built for the Taig mill. I have bought a commercial unit but find that they are simply too large and tend to vibrate when boring large holes and the boring tool is displaced laterally. They are commonly threaded for use with diferent arbors. My unit is much smaller and so there is a lot less mass to add cause as much vibration. The heavier the mill, the more it will tend to absorb the vibrations due to the offset tool. I also sell a video that documents the complete construction of this unit. See the boring bar at: http://www.homestead.com/tool20895/arbacc.html and check out my site at http://www.homestead.com/tool20895/jose7x10taig.html Look for the video section for info. Thanks Jose ------- Date: Wed, 26 Sep 2001 21:53:41 -0500 From: "jerdal" Subject: Re: Re: Wanted: A boring bar holder for a 12" ATLAS I made a holder by just drilling appropriate sized holes into a block of aluminum using drill in the chuck and the block fastened to the compound. Gets it right on center. While not a split type, I think the block may be just as usable. One hole through for a 1/2 or 3/8 bolt to hold it, and a few set screw holes finish it off. Got the idea from a Rudy Kouhaupt article in HSM, saw such a block in one of his setups, and decided it was a good idea. I faced the block square and put in the hold-down bolt hole first. Naturally, some time later I found the compound t slot top was a bit convex and had to take it over to the shaper to plane it flat, now I must use a shim to get back on center, or make a new one. Lazyness has won, I use a shim. Jerry ------- Date: Fri, 28 Sep 2001 03:17:43 -0000 From: "Horace Steven" Subject: Re: Wanted: A boring bar holder for a 12" ATLAS I made mine similar, I got a block of steel (1.5 Thick x 2 x 3 )), drilled 2 holes thru the flat next to one edge, then bolted to the compound with 2 large bolts with heads machined to fit slot, then bored a 5/8" hole thru it long ways. Made several sleeves for different sized bars, and slotted the large block thru the side with the 2 holddown holes and the adaptors also, line up the slots in adaptors when clamping down with smaller bars. Worked fine. Steve ------- Date: Tue, 30 Oct 2001 00:55:45 -0000 From: zr1zr1x~xxnetzero.net Subject: machining question I would like to machine a 1.5" diameter hole in a bar of aluminum whose dimensions are 3"x3"x7". I wish the hole to be 1.5" in diameter that is 7" long. I have a 12x36 Atlas lathe but no mill at this time. Is this something feasible to do in my lathe? If so; do I mount the aluminum bar in a faceplate or 4 jaw chuck and use a boring bar with the lathe in a slow rpm or do I invest in a boring head that has a MT3 tapered tang/drawbar and mount the aluminum bar in the milling adapter? I am assuming that the 7" depth is somewhat of an challenge. As you can see I am a novice with few local folks to ask this question. I appreciate your time giving me a bit of guideance. Regards, Rick W. ------- Date: Mon, 29 Oct 2001 20:09:20 -0500 From: Charles Gallo Subject: Re: machining question > I would like to machine a 1.5" diameter hole in a bar of aluminum > whose dimensions are 3"x3"x7". I wish the hole to be 1.5" in > diameter that is 7" long. A 7" overhang is going to be a dog no matter what you do - the overhang of the work itself is bad. IF you have a steady rest, and have enough extra stock I's turn a small round at the outboard end so you can run it in the steady. If you don't... Chuck it up in a 4 jaw chuck, and DRILL as large as you can ALL the way through (even if you have to drill from both ends), now put the largest diameter boring bar that you have that fits in, and go to work - take fine cuts, and take the occasional "spring" pass (aka where you don't change the depth setting). If you have a solid carbide boring bar, it'll work better, as it's stiffer. ------- Date: Mon, 29 Oct 2001 20:23:19 -0500 From: "Paul & Charlene Wilson" Subject: Re: machining question Rick, I wouldn't hesitate to bore this size hole, but perhaps more experienced folks might. I think the first step would be to drill as large a hole as possible - 1.25" to the right depth, then rig a boring bar as stiff as you can get. The large starting hole will help. I have seen boring bars 3/4" diameter with a tool inserted through a hole in the end that is drilled at the proper angle, and a set screw to hold the tool. Then it is just a matter of grinding the tool properly. Take light cuts to avoid cone shaped hole and you should be in good shape. Paul ------- Date: Mon, 29 Oct 2001 21:57:17 -0600 From: Jim Irwin Subject: Re: machining question I have read about five responses to this and can hardly believe what I'm seeing! Such a task is not all that hard to accomplish. Depends some on what aluminum alloy you're boring, and the tolerances and finishes required. For "normal" tolerances and finishes, though, just chuck it up in a four-jaw (yours does have fresh ground gripping surfaces, doesn't it?), center drill it, then drill a 1/2 in hole as deeply as you can, then drill it out with a 1 1/2 inch drill. Don't have one? Call around and rent one! A well ground drill should give you a hole no more than .003 oversize. Chatter? Probably need to increase feed rate or spindle speed or both. Use good lube. If doing this on an Atlas, you probably don't have mist or flood coolant capability, but can use a squirt or spray bottle of water soluable oil to do the trick. Can get messy, though. Need tighter tolerances or finer finish? Use a slightly smaller drill and ream to size (rent them both). Must do it with what tools you have at hand? How big can you drill it? Eventually you must have a bar long enough and stout enough to do a single pass to final dimension full length. Before this time, you will be able to go at it from both ends sequentially (though this will be a supreme pain in the ass with all the set-ups). Or you can make a spade-shaped drill/reamer using tool steel and a CRS shaft as large as can fit your tailstock chuck. Just remember that the vast majority of the material to be removed requires no finesse. It's just the final pass(es) that must be "right". I would want (or make) at least a 1 in dia boring bar and clamp it just long enough to reach full length, ane leave enough out the far end to hold onto to dampen out most vibration. Good luck! Best regards, Jim Irwin ------- Date: Tue, 30 Oct 2001 13:43:42 -0000 From: "John Lawson" Subject: Large diameter bored hole Many years ago, I bought an Atlas boring table for the cross slide of my 12" lathe. It will work with smaller items clamped to its surface, but the project mentioned places the center of the hole above the lathe's centers. Therefore, the between centers boring bar will not work in this instance. You can see an illustration in the Atlas manual. Incidentally, the boring table was used as the table on the Atlas double cross slide and rotating table device sold for drill presses thirty-some years ago. As mentioned, it is only useful for small diameter workpieces. I picked a common diameter (1 inch) and made a 60 degree center to fit. By placing the workpiece on the boring table with the center in position and holding it next to the live center, you can easily determine whether the job fits, and if so, how much packing you need under the part. Unfortunately, there is only one groove to mount a clamp, across the center of the table, so it will have to be a rather wide clamp and you may wish to re-enforce it with c clamps. Needless to say, one locks down the swivel very tightly during boring. The job mentioned would best be done klusing a chuck and center rest and the largest boring bar that will fit the Armstrong boring bar holder. With a bit of ingenuity and loads of patience, I have dome similar work with this setup. It would pay to grind a v groove down the boring bar to the toolbit position and drip aluminum coolant/lube while machining with that length of overhang. Proceeding very carefully, it could be done with the 3/4" boring bar. Hairy, but possible. Been there, done that, having no alternative. There is no way to insure that the bore will not be tapered cutting in only one direction, so grind a double edged toolbit and cut forward and back. ------- Date: Wed, 7 Nov 2001 11:11:06 -0800 From: Frank Evan Perdicaro Subject: Simple bore issue >I am converting my 12" Atlas lathe to a variable drive using a DC treadmill motor from the surplus center. I know a lot of you have already done this conversion. My question is, where do you find a 1/2" v-groove pulley to fit the 17mm shaft on the motor? 17mm is slightly larger than 5/8". I have no way to bore a pulley to the correct size.< No way? I thought that once. A pulley is not a particularly hard thing to bore. I have both an AA and an Atlas. Before I got the Atlas the AA was in tough shape. The planetary was shot and there was no way to spin the spindle. That weird spindle size meant I could not use a standard pulley on it. At the suggestion of a friend, I made a simple "follower drill", sort of a poor man's counterbore. In that sitation I used 1/2" drill rod, 3/16" drill rod and a 1/4-20 cap screw. Cut off an 8" section of 1/2" drill rod, then cross drill a 3/16 hole 1" from the end. Drill and tap the end for the 1/4-20 bolt so it can hold a section of 3/16 drill rod in the cross- drilled hole. Make a simple cutter with the 3/16 drill rod. Harden and temper. Insert and set depth. Clamp. Slather everything up with oil and go at it. I made a 0.55" hole where a 0.50" hole used to be in a zinc pulley in one pass. In your case you could do the same for 17mm. Although it is best to use a drill press, you can even do this with a hand drill. ------- Date: Sun, 9 Jun 2002 08:52:44 -0500 From: "jerdal" Subject: Re: Boring tools and toolholders > Might anybody have plans for a design that I can make myself and use > in my existing toolpost? Simplest boring tool holder is: Get a chunk of aluminum about 2 x 2 x 3. Or to suit if lathe is different from mine. Idea is that the spindle centerline should be half to 2/3 of the way up the block when on the compound. Drill a hole through vertically for the hold-down. A 3/8 bolt should work OK. Make or buy a t-nut to fit the bolt you use. Now mount the block on the compound, long side parallel to the spindle. Move to set the block such that a drill in the chuck will make a hole on the far side of the block face, i.e. on the other side of the mounting bolt from you. Drill into the block to fit one side of boring bar, typically 1/2 inch diameter. If you will use stub bars, you can go in an inch or 1.5 inch. Otherwise you may want to drill through. Flip block and drill from opposite end in same manner for another size bar, typically 3/8 diameter. Drill down into each hole from above, and tap for set screws. Clean up and you now have a very solid bar holder. Notes: Make sure your holes will not intersect the hold-down bolt hole before starting to drill! Drill to a very close sliding fit, using a sharp drill. I would say bore them, but you don't yet have a boring setup. DO NOT bother with any type of boring bar holder that involves your lantern post. 1) they are not solid, and chatter easily 2) if they come loose, they get wound up in the work or thrown off, not pretty. Jerry ------- Date: Sun, 09 Jun 2002 13:25:17 -0400 From: Stan Stocker Subject: Re: Boring tools and toolholders I'd agree with this approach, and have been quite pleased with the results. The only suggestion I'd add is rather than have set screws bearing directly on the shank of the boring bar, that you cut a slot from the side to the bore, then drill and tap for studs to allow the entire block to become a large clamp. The holes above the slot are clearance drilled, the hole below the slot is tapped. Loctite the studs in, add a washer and nut to the top of each one. Threads in aluminum tend to gall under high torque with repeated usage. You could, if you prefer, helicoil for the set screws if you prefer the setscrew to clamp directly on the shank of the bar. My 4 way tool posts are done with helicoils for the setscrews that clamp the tools for this reason. Stan ------- Date: Tue, 16 Jul 2002 08:40:37 +0200 From: "Jaime Alemany" Subject: Boring tool or flying cutter?: dangerous situation [SHERLINE GROUP] Last session at the shop I had a most distasteful situation: I was boring a set of holes, changing the boring head from the "small hole" position to the "big hole" to reach the intended diameter. Just after the change in one of them, and after the first pass, the boring tool with its corresponding head part went flying away, high speed... Fortunately, it didn't hit me, and no one else was at the workshop (I must thank God for that, my 3 year old son is usually around me, with his odd-looking glasses, asking me questions about the mill and the lathe...). The tool landed some 3 meter away from my mill. Seems I left the screw too loose (yes, that's what happened). After finishing the holes (with some aditional sturdy protection for my body), I re-read sherline's instructions to see if I had forgotten something, as I read them quite long away now (BTW, I had bored a *lot* of holes previously with no problem whatsoever). Well, I didn't. The problem is "tight enough to...but loose enough to...". Of course, it's my fault an only my fault, and I should have know, and I should have tightened the screw enough, but, as a suggestion, I'd include some big warning - thinking about it, it's one of the most dangerous tools, as the potential to become a "true flying cutter" is the highest. I'm now trying to devise a security device to hold the boring head in case of slip, any ideas? Anyone else has had this problem? Thanks, jaime ------- Date: Wed, 17 Jul 2002 08:58:57 +0800 From: "Lam" Subject: Re: Digest Number 812 I don't know about security device to hold the boring head in case of slip but you could always build a clear acrylic shield that will at least block / deflect or slow down any tools that decide to take off. The shield will also stop chips from flying too far. Lam ------- Date: Tue, 16 Jul 2002 10:31:20 -0000 From: "variousgroups" Subject: Re: Boring tool or flying cutter?: dangerous situation Looks like there's been a couple of solutions offered for this really dangerous problem, but the solutions might not be able to work well with the Sherline. If you try out the Patent Office web site at www.uspto.gov and then click your way over to the patent number search, and try looking for 6,135,684 and 5,396,693, there might be something in these patents, which are all still good by the way. To see the images and not just the text you have to have a tiff reader on your computer, which the new computers all have, but which I had to download and install first. I'm not involved with these gents in any way so I'm not promoting their solutions, but I just noticed them when I looked after reading you question. Any suggestions about a chip guard for the y-axis on the mill? Mike ------- Date: Mon, 22 Jul 2002 20:31:49 -0400 From: Stan Stocker Subject: Re: Drilling 1" hole "Mr. Sinbad" wrote: > I'm not quite sure what the best way is to drill a 1" > hole in 1/2" plate aluminum. Is this do-able on my > taig lathe or should I use my drill press. Do I use a > boring bar? Thanks for any suggestions. Assuming the plate can be mounted securely to a faceplate or held in the 4 jaw chuck without hitting the bed, you'll need to step drill up to the largest size bit you have that can be held in the tailstock drill chuck. I'd finish with a boring bar to get to final dimension. I don't think I'd try using a reduced shank 1 inch bit held on the tailstock ram. If a drilled hole is suitable for your intended application, then doing a hole of this size is probably better done on the drill press. I tend not to drill any holes larger in diameter than the tailstock ram diameter (on any of my lathes), and when I get into the larger sizes I step drill in 1/8 inch increments. I'd start in this case with a center or spotting drill, poke the initial hole with a 1/4 inch bit, then go 3/8, 1/2, 5/8, 3/4, 7/8 then 1 inch. On a somewhat larger lathe I might go in 1/4 inch steps. Big holes get drilled on the mill whenever possible. Stan ------- Date: Tue, 5 Nov 2002 22:52:41 -0800 From: "Dave Hylands" Subject: RE: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? In case anybody is still looking (or doesn't want to look), It's at the bottom of this page: http://www.lesgrenz.homestead.com/BasementShop.html Dave Hylands Vancouver, BC, Canada http://www.davehylands.com/ ------- Date: Wed, 06 Nov 2002 15:32:30 -0000 From: "les_grenz" Subject: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? Chris, I don't usually cut off the drill bits. I just grind the tip until I get past the coned tip. Then just grind a small relief on the front end of the drill. The side relief is already there. Try it. You'll like it. Les http://lesgrenz.homestead.com/Leshomepage.html ------- Date: Thu, 07 Nov 2002 01:02:18 -0000 From: "les_grenz" Subject: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? Drilling is a roughing operation. Reaming will make the hole accurate in dimension only but not in location. Where accurate placement or concentricity is required, I would drill undersize, bore to within a couple of thou of finished size and then ream to size. I would only ream if extreme accuracy is needed otherwise I would dispense with the reamer and just bore to size checking with a go-no-go gauge if the hole is too small to measure with traditional methods. Les http://lesgrenz.homestead.com/Leshomepage.html ------- Date: Wed, 6 Nov 2002 20:05:28 -0600 From: "jwalters" Subject: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? Bruce: Reamers and boring bars each have their own strength. A quality reamer with a predrilled hole .010/.015 undersize with good coolant, a good setup and speeds/feeds should maintain a hole size within .0002 of the reamer size part after part. The down side is that a reamer is only good for one size. A boring bar will finish a hole to any size within a range. The limitation is that the bore can only be as accurate as the gaging method and maintaining a consistent hole size requires a quality machine with tight gibs and lead screw with constant attention to detail. I have a variety of reamers and boring bars in my shop to take advantage of the strength of each. I hope this helps John ------- Date: Thu, 7 Nov 2002 03:04:43 -0600 From: "Matt Pierce" Subject: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? I don't bore anything I have a drill bit for, but I'm lazy ;-) that means larger than 1/2 inch for me. If I had the option, I'd drill and ream. Matt Pierce ------- Date: Sun, 10 Nov 2002 06:29:06 -0000 From: "chris_vinluan" Subject: Re: Drill bit as a boring bar? Or easy to make, tiny boring bars? I found something else that can be used as a boring bar that is also easily sharpened, unlike a drill bit. Straight style router bits! It comes in HSS and carbide. Another plus is that they already have 1/4" shanks, so no need for special holders. I found a 1/8" straight bit that works perfect. All you have to do is angle to tool post for side clearance. They are more expensive than drill bits, but they are very "plug and play". Chris ------- Date: Tue, 27 May 2003 16:36:11 -0400 (EDT) From: Kirk M Scammon Subject: Re: "rope" chatter >>> The idea is that the vibration leaves a pattern on the work, and >>> the next revolution, the pattern reinforces the vibration, >>> creating a resonance that keeps on building. This is what usually >>> limits my roughing >> Sometimes I have seen a chatter mark that makes the work look as if it >> was made of rope. Once that starts it is hard to stop unless you take >> a deeper cut, but when close to desired size you can't do that. A trick >> that sometimes works for me is to wrap some fairly heavy wire solder >> around the tool. That seems to dampen the vibration or chance the >> resonent frequency enough to stop the >> chatter. Works especially well on boring bars. On Tue, 27 May 2003, Frank Evan Perdicaro wrote: > We ran into this problem yesterday. I am working on a golf ball cannon > for the 4th of July. After some preliminary work, the cannon was > mounted vertically on my mill and bored with a 1 3/4" 2 flute endmill. > Even with a light cut and heavy oil, plus full immersion on the tool, > the result is a chatter pattern that looks like light rifling. Try putting an old rag over the hole and then run the cutter down into the work. I have found that this works well when counterboring large screw holes. It both cuts down on the chattering noise and gives a better finnish to the work. Kirk 12x35 A/C and MF mill ------- Date: Tue, 27 May 2003 17:38:36 EDT From: n8as1x~xxaol.com Subject: Re: "rope" chatter be sure the chuck jaws are not worn bell mouth , & fail to catch on the ends ...i had worn chuck jaws that turned parts that looked like a spline ,,,,,,light carbide cut cleared it up best wishes docn8as ------- Date: Fri, 5 Sep 2003 14:30:33 -0400 From: "mertbaker" Subject: Re: Digest Number 1613 [NOTE TO FILE: this next quoted suggestion was close to an old boring method for finishing the interior of an already-hollow cylinder but missed an important point -- the cylinder does not rotate.] > Essentially you put a big bar between the headstock and tailstock, > and then have a cutter that rides on the bar do the boring. In order for this to work, there has to be relative motion between the toolbit & the workpiece. If both are held in the HS, they will both turn, & there will be no relative motion. In those old boring setups, the cylinder, open at both ends, was mounted on the carriage, the boring tool turned by the spindle, and supported by the TS center. When I bored my 2-5/8 bore mortar, I used a 2" dia boring bar held in a block on the cross slide. The cutter was a carbide triangle bolted on a short flat milled across the bar. Mert ------- Date: Fri, 5 Sep 2003 16:43:50 -0500 (CDT) From: dswrx~xxwebtv.net Subject: Re: Digest Number 1613 A fly in the ointment... If you mount the boring bar between centers (i think this is called line boring), you must align the center of the bore in the workpiece with the center line of the lathe. (not an easy task... for me, at least) 8-) Leo (pearland, tx) ------- Date: Fri, 26 Sep 2003 23:00:16 -0400 From: "James Leatherwood" Subject: Re: Bore a cylinder [posted to sherline group] > Hi, I'm very new to lathe and have a general question. If I want to > bore a 1'' inside diameter cylinder, what tool should I use to do > that? Also, do I need to build my own tool, or there is a tool for > this purpose, and if it is, what is it called and what size should I > use? If I have to make my own tool for boring a cylinder, then how > should I make the tool? Thanks All you need is a standard boring bar with enough length to reach the full length of the bore. I have just finished boring out the cyl for my latest engine, it is a 7/8 bore. I first drilled out the hole as large as I could in my case I went 3/4 of an inch to leave plenty of room to make sure the bore was straight, Drill bits do a terrible job of cutting round or straight holes. With a bore of that size I would recommend a 3/8 shank boring bar to fit in the standard sherline tool post. Sherline sells boring bars but I am not sure they have enough length depending on what you are building. MSC, ENCO, and many others sell boring bars from cheap HSS and carbide to Indexable carbide. The main thing that you need to be careful with is that you need to take it slow (small cuts). Again depending on what type of material you will be cutting. The closer you get to the size the smaller you need to cut. If you have to maintain tight tolerances between the bore and the piston then I would suggest you make the hole .002-.003 smaller than you need. Then make a lap out of some aluminum and using lapping compound (found at most auto stores); lap the cyl to the correct size. This will ensure that the bore is cylindrical and will remove the tool marks and smooth the bore up. Hope that helps. shorty. ------- Date: Tue, 10 Feb 2004 15:50:13 -0000 From: "Chet R Biggerstaff" Subject: Cold soft steel problems I am making a tailstock die holder for my Taig and am having problems cutting the steel. I boared a hole out so that I could use a boaring bar to enlarge the hole for the dies and to enlarge the center part so that it is true to the rest of the part and can be threaded for the tailstock. The problem is that I can only take 1-2 thous at a time running at the second to highest speed on the lathe. I am using carbide boaring bars to make the holes larger. What can be cuasing my problem? ------- Date: Tue, 10 Feb 2004 11:26:08 -0500 From: Stan Stocker Subject: Re: Cold soft steel problems Hi Chet, a boaring bar is for use on wild pigs, not steel :-) Try dropping your speed for starters, it sounds like you are running sort of fast for steel on this size machine. Carbide may be working against you as well. In a small bore it's hard to get the tool position and cutter geometry set up to maintain a positive rake. The thickness of the carbide insert may be too much, dragging its heel in the bore rather than staying clear of the bore. If you have a round boring bar holder for your lathe, you might try using a 2 flute endmill as a boring bar. You set it up just like a boring bar, ignoring the other cutting edge hanging out in space. Gives nice rake and chip removal. Cheers, Stan ------- Date: Tue, 10 Feb 2004 16:43:14 -0600 From: "Bad Brad" Subject: RE: Cold soft steel problems If you are trying to turn cold (rolled?) steel, it is fairly hard to get a good setup that works well (it looks like a rat gnawed on it while it is being turned). I always try to run my boring cutter slightly higher than dead center to prevent the bit from hogging (diving to deep). Boring like parting requires a reduction in speed and depth of cut. Use some type of cutting fluid. Check the edge of your carbide tool for chips, a loop works great to find the smallest chips). A chipped edge can prevent the bit from starting a cut. Bad Brad Rabid Weasel Racing Team ------- Date: Tue, 10 Feb 2004 23:02:22 -0000 From: "Robin S." Subject: Re: Cold soft steel problems Forget carbide. You want a HSS boring bar. Either buy one, or grind one using a square blank. You want neutral or slightly positive rake, a small nose radius (like 1/64") and a fair amount of front clearance. You'll have to go slow due to the small nose radius and the substantial front clearance but you should be able to take a fair amount off. If you don't have too much trouble taking a *heavy* depth of cut, try increasing your nose radius to improve your finish. DO NOT have your tool stick out ANY farther than it NEEDS to be! This will cause chatter. Also, start at the lowest spindle speed and increase it until the performance of your setup goes south. HTH. Regards, Robin ------- Date: Wed, 12 May 2004 20:09:01 -0000 From: "jeastwoodlm" Subject: Re: Boring depth - Aluminum In sherlinex~xxyahoogroups.com, Joe B wrote: > I need to bore a blind cylinder hole 1"Dia. x 2 21/32" deep. My first > problem here is I can't find a boring tool 2 3/4" long as respects > the bore depth with a 3/8" shank. Can this be done on the Sherline > mill or lathe? If so, any recommendations as to how I should proceed? > I forgot to mention that the work piece is 3 1/4" in length with a 2"OD. Add www.mscdirect.com to your list of tool suppliers. They have 3" long boring tools with 3/8" shanks. I've ordered from them many times. ------- Date: Wed, 12 May 2004 17:31:02 -0400 From: "Jerry Glickstein" Subject: Re: Boring depth - Aluminum Joe, yes, your boring job can be done on either machine. Do you have a four jaw chuck for the lathe? Holds better than a three jaw. Chuck up your work. Get it running concentrically with a dial test indicator. Since it is 3 1/4" long, it is a good idea to support it with a steady rest. Then, face the end to true it up and give you a reference surface. Centerdrill it. Drill it with successive drills to approach the 1" Dia bore. If you can't find drills large enough, you need to do more boring. :) Do not rush it. You do not want to knock your piece out of alignment. If you have a milling machine, you can make your own boring bar. On the milling machine. Clamp your piece vertically in a V block which is fastened to the table. Don't have a V Block? Make one. Or use an angle plate or make one. You notice I believe in the old saying "The lord helps those who help themselves". :) A vise is too shallow to support the piece properly. Then, With a dial test indicator in the spindle, adjust the X and Y axis until the cylinder C/L is coincidental with the rotation of the dial indicator in the spindle. Lock the table. Proceed as in the lathe except for the facing operation. Easy does it. Light cuts and you will get there. If you don't have a boring head, you can set up your piece in a four jaw chuck on the rotary table using end mills. I do not know how much you know, so please excuse me spelling things out. If you have any questions, just contact me offlist. Regards, Jerry G (Glickstein) chieftoolmakerx~xxearthlink.net 718-969-2236. ------- Date: Wed, 12 May 2004 23:32:27 -0400 From: "Shorty Leatherwood" Subject: Re: Boring depth - Aluminum Joe, Yes it is possible on the Sherline. I would recommend checking with www.mscdirect.com I purchased a "circle c" boring bar for something like $80 bucks and it came with 10 carbide replacement cutters, this may be a little expensive but you can get a cheap brazed boring bar set that will give you enough reach from MSC or off ebay for somewhere around $19 and do the same thing. I just bored the cyl for my latest motor and it was out of a 2in OD piece of aluminum, the bore was not as deep only 2 in but I have done much deeper, the thing that you have to remember is that you will get a lot of tool deflection being that long so you have to take light cuts. the steady rest and 4 jaw chuck that jerry mentioned will also make things much easier. hope that helps. shorty. ------- Date: Thu, 13 May 2004 13:51:47 EDT From: joeb759x~xxaol.com Subject: Re: Boring depth - Aluminum Many thanks to all that replied. I did look at the MFC big book but failed to find a bore tool that will give me the depth I need with a 3/8" shank. They go up to 2 1/4" in depth, then jump to a larger shank size.. I don't believe the Sherline steady rest will hold 2" OD work but I will check on this also. Thanks again guys. Joe Baker Brookfield CT. [NOTE TO FILE: Jerry then replied that an adapter might be made to use a boring tool with larger shank. Adapters for smaller machines like the Sherline or Taig for tool shanks up to 1/2 inch have been discussed before in their files, often using a blank arbor from Taig. It might be better for stiffness to make a custom boring bar, or set of boring bars; such a set would likely find many future uses.] ------- NOTE TO FILE: There is a discussion involving drilling, boring and reaming starting on 8 Aug 2004 (called "Tail Stock") that has been placed in the Drilling Tips file. Worth a read. Don't forget the Lapping and Reaming file. ------- Date: Wed, 11 Aug 2004 22:44:28 -0000 From: "nigelhitmiss" Subject: Cyl .boring mistake [Min_Int_Comb_Eng group] I am making a 1 cyl hit and miss model engine. The plans call for a bore of 1.125" and I am now at 1.200". Should I go to 1 1/4" bore or get more cast iron and start over. I have not started the piston or rings. This is my first project. Thanks. Nigel ------- Date: Thu, 12 Aug 2004 01:02:58 +0200 From: "Frank Hasieber" Subject: RE: Cyl .boring mistake Hi, stay where you are and adjust accordingly, it won't make much difference. Unless you want to stick strictly to the drawings. Engineers use drawings, builders (homes/architects)use plans! Frank ------- Date: Thu, 12 Aug 2004 09:10:07 +1000 From: "Ron Chernich" Subject: Re: Cyl .boring mistake Cast iron is expensive, and cleaning up after machining it is such a chore, but you probably don't have to make the final decision just yet. You'll probably pick up a couple more thou honing, so delay the decision until you've done that and scrap/use based on how pleased you are with the fully finished product. If your bore is round, regular, smooth, and the cylinder liner walls not paper thin, I'd say go with the 12% swept volume increase. rc ------- Date: Wed, 11 Aug 2004 18:50:14 -0700 (PDT) From: Reg Miller Subject: Re: Cyl .boring mistake I had the same problem a few years ago ,I was asked to repair a hit and miss that would not run. After tear down I found the cylinder bore .060" oversize and with .017" taper. When I got the thing straightened out it was .100" oversize. I did not dare to open it up further as the bore was getting very close to the head studs. I made the head gasket from .030" copper, new piston and fabricated rings and the thing ran like a charm. Take a good look at the head and you might have to move the studs a bit. good luck Reg ------- Date: Tue, 14 Sep 2004 05:07:09 -0000 From: "Jim Knighton" Subject: Re: Left hand boring tool for mill boring head In sherlinex~xxyahoogroups.com, "pest3125" wrote: > I was wondering if someone knows a source for a left hand > boring tool for the Sherline Mill Boring Head? Check out the MSC on-line catalog (www.mscdirect.com), page 718. They list both right and left handed boring bars with 3/8 shanks as well as other sizes. I'm not a fan of the Sherline boring head, either. While you can certainly build your own (something that really appeals to some hobbyists), there are commercially available alternatives. For instance, I have a 1.5" Criterion Tinymite boring head that I use on my Sherline mills. It has a 1/2" integral shank and when mated with a 1/2" end mill holder it works just fine. It operates exactly as do the larger Criterion models and their clones. 1/2" end mill holders are available from Taig guru and dealer Nick Carter http://www.cartertools.com/em.html I have several of his holders, FWIW. He's also a good guy to deal with. Highly recommended. Being Taig arbors, you have to machine off the 3/16" registration recess just ahead of the threads. This isn't a big deal, and only takes a few minutes. Please note that Nick Carter is also offering an arbor with 7/8" x 20 tpi threads. A photo is on the above page. This is the thread pattern used by numerous makers of small boring heads. With this particular arbor you can mount all manner of commercial boring heads to the Sherline mills, but we need to use some common sense here. Big heavy boring heads aren't going to work very well on a small light milling machine. I purchased one of these arbors and mounted my 2" Criterion boring head to my 2000 mill. In my opinion, I wouldn't think about using a boring head any larger than this - and this setup is marginal at best. It works, but if you aren't careful you'll end up chasing your mill all around the shop or breaking something. Keep the speed slow if you try this. I can get my 2000 mill really rocking and rolling with the smaller Tinymite model. On the other hand, these are well made and easy to use tools - and these aren't adjectives I use to describe the Sherline accessory. It really suffers in comparison to the Criterions and other similar boring heads. While the Criterion boring heads are somewhat pricey, there are other similarly sized tools available from other sources. The least expensive model of this type that I know about is from Little Machine Shop. They have a boring head that is at least cosmetically similar that sells for abt $50. I haven't used it so I can't comment on it or vouch for its quality/precision/etc. I hope this helps some. Regards, Jim Knighton ------- Date: Tue, 28 Dec 2004 02:12:00 -0000 From: "gehaddad" Subject: Boring a blind hole [TAIGTOOLS GROUP] Using the Taig boring tool, I'm only able to get a conical bottom to my blind hole. What's the trick to getting a flat bottom blind hole? The bore was 0.550 in, so there isn't much room for movement of the boring tool. Thanks ------- Date: Tue, 28 Dec 2004 10:17:49 +0000 From: Steve Blackmore Subject: Re: Boring a blind hole Use a "slot drill" or centre cutting "end mill" to finish the bottom. Steve Blackmore ------- Date: Sat, 1 Jan 2005 21:23:13 -0600 From: Subject: Re: Boring a blind hole To make a true flat bottom in a blind bore requires a boring bar less than 1/2 the size of the blind bore with the tool set as close to center as possible. The bar must travel past the center of the bore. Assuming that you do not have a 1/4" boring bar. Make one up from round water hardening tool steel. Heat treat to full hardness. Grind the required geometry in the end of the bar. Try to keep the outside cutting point of the tool close to the tool shank size. A simple bar with the correct geometry, height and diameter should be able to make a true flat bottom. John ------- NOTE TO FILE: Marcus contributed to this next thread in the Sherline group, but his first new message was placed earlier in this file with his prior 18 Feb 2001 message as to why he does not use Sherline's boring head; he has an alternative. As to why this thread dealing initially with Sherline equipment was placed here -- there are generic ideas anyone might use. THE FIRST PART OF THE THREAD DEALS WITH DISSATISFACTION WITH BORING HEADS. (BUT ALL PARTS OF THE THREAD HAVE THE SAME SUBJECT TITLE.) ------- From: bdmail Sent: Sunday, January 02, 2005 10:04 AM Subject: [sherline] Boring Head Inaccuracy! A 4-40 screw ?!?! I have had this thing for a year now, and keep forgetting to ask someone until I am trying to use it........ Is this boring head really supposed to be marked in thousands of on inch when it all depends on the TIP OF THIS 4-40 SCREW to push on that pin inside?? Is the obvious answer to put it on the lathe and turn it? It just seems like it will be hard to make that end push ACCURATELY and WITHOUT BINDING on that post inside. I assume SOMEONE else has had this problem. Any Help would be appreciated, of course. Bernie ------- From: Jerry G To: sherlinex~xxyahoogroups.com Sent: Sunday, January 02, 2005 7:46 AM Subject: Re: [sherline] Boring Head Inaccuracy! A 4-40 screw ?!?! Bernie, I have the boring head. It is not worth anything to me. I am sorry I bought it. I do not like the design. I do not like the fact that it does not adjust in both directions, plus what you point out. So, I made my own that works great.... Direct reading with .001" graduations, so you can split the .0001" 's... If you send me your e-mail address, I will send you a photo. Regards, Jerry G P.S. Or go to the [sherline group] Photo Section. Click on Show All. I have four photos posted on the lower section. ------- Date: Sun, 02 Jan 2005 21:00:45 -0500 From: bdmail Subject: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Success I think....And not too bad time wise either..... I remember that I was mad at one point this year about the Boring tool, and when I ordered a stock of "replacement" parts, from Sherline, I spoke to the nice woman there, and explained my problem, and I offered to fix it myself if she sent me an extra one of the 4-40 screws with the THOUSANDths marked on it - from the Boring tool (its around SIX dollars, if you can believe it!!) So I had an extra to play with, is what I'm getting to. ANYWAY...I couldn't get mine on my lathe, because the SCREW is too short, (the dial got in the way) so I actually grabbed it in the VISE pointing UP, with some square pieces of metal (to reach over the dial) grabbing it, and put the vise on the ROTARY TABLE....this way it would be nice and even all around. Yes, mounting it this way was a pain in the ass, but it worked for me. TEST: -I Put the DIAL-SCREW back in the BORING HEAD and then put an indicator on the side of it.... -I tightened the boring head lock just enough to slide snugly. -I carefully turned the boring head DIAL SCREW and checked to see that for every 1 THOUSANDth I turned the DIAL, I got 1/2 a THOUSANDth of indication......(*****WATCH OUT----the boring head is marked in "thousandths Change in Diameter", so moving the dial one thousandth will actually move it 1/2 thousandth******) Maybe they thought people with a mill might not have a lathe? I don't know. All seems good now, though. And it seems to act well throughout the whole rotation of the DIAL. I did not check this with a cut, that is tomorrow. What I PLAN to do, is make a "GUIDE BUSHING" out of a brass or nylon 4-40 nut, and drill it out and stick it on the inside to support the free end of that 4-40 screw so it stays right on that dowel in there (open it up, you will see). I have hope for it. Let me know if I made myself understandable!!! Bernie p.s. I forgot to mention this.....the rotary table thing is just to mimic a lathe action....a uniform face - square in referance to the length of the screw....then as you turn the dial, sthe surface of the end of the screw won't act like a warped record, and push on that dowel like a record needle. ------- Date: Sun, 02 Jan 2005 21:46:49 -0000 From: "Jim Knighton" Subject: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! In sherlinex~xxyahoogroups.com, Geert De Pecker wrote: > Jim, I agree concerning the sherline boring head and the criterion seems > quite nice. One question/remark however: it seems quite a bit longer > then the sherline head and I'm wondering if you still have enough work > envelope with it? Geert, you are right that the Criterion head is a bit longer. It's also a bit heavier, but not as much as you might expect - a few ounces. The photo exaggerates the apparent length. The Taigesque adapter screws on the spindle threads and is long enough to hold the integral shank without modification. This is in contrast to the Sherline with its 1MT shank held in the spindle bore. The boring bars I use are quite short, however, and so far I haven't had a problem. I usually use this setup on my 2000 mill and I've done a couple of minor (almost trivial) modifications to it that give me more usable height on the z axis. While it's no doubt a function of the nature of the pieces being milled, I don't seem to have much of problem in this regard. All of these issues are tradeoffs. The ideal boring head would be no longer/heavier than than the Sherline and with the capacity, adjustability, and precision of the Criterion. You might get there with a shop-built accessory, but the Criterion is as close as I've found commercially. It works for me. Regards, Jim ------- Date: Mon, 03 Jan 2005 00:36:37 -0000 From: "psychlingdude" Subject: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! >then the sherline head and I'm wondering if you still have enough >work envelope with it? Geert I'm using the 1.5" Tinymight with the optional 7/8"-20 threaded mounting hole rather than the 1/2" shank. I machined a threaded adaptor out of 12L14 with a 7/8"-20 OD and 3/4"-16 ID with a 1/8" long shoulder on one end that seats against the body of the boring head when it is screwed in. The boring head then mounts directly onto the spindle. Compared to the Sherline head there is a loss of 5/8" to the work envelope. With the Taig arbor arrangement, using the boring head with the 1/2" mounting shank, your loss is about 1 1/4". Roger Heniges ------- Date: Sun, 2 Jan 2005 17:08:39 -0500 From: "Jerry G" Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Hi Jim! How are you doing? Two things... One, the boring head I made is aluminum to keep the mass and centrifugal force down. However, I "stole" the adjusting screw from a Criterion boring head.... With a dovetail slide, of course. Two, have you ever used any "Truemade Boring Bars"? They have adapters, with .375"diameter shank. And Boring Bars from .027" to .480". (with a .625" diameter shank) to me, the best. I have no commercial connection, just a satisfied customer. Regards, Jerry G (Glickstein) ------- Date: Sun, 02 Jan 2005 22:16:42 -0000 From: "Jim Knighton" Subject: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Jerry, thanks for the advice. I've not seen the boring bars you mentioned. The ones I use are also from Criterion and are solid carbide. They work great, but I can foresee the day when I'll want other sizes, and probably smaller than I'm currently using. I'm getting by, all things considered. Thanks for your continued interest. Regards, Jim ------- Date: Mon, 03 Jan 2005 00:07:01 -0000 From: "n2562001" Subject: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! The Sherline boring head is not designed the way I would have designed it. However the minor deficiencies have not been enough to make it worth my time to build my own. On the plus side it is as rigid as a boring head will be of this size and is a good size match to the mill. On the down side the 4-40 thread was loose enough that it would not stay on setting making it a pain to use. This was easily corrected with a punch mark over the thread because I was too lazy to install a spring loaded plunger as a proper fix. When I make an adjustment I loosen the set screw and adjust the calibrated wheel as needed. From that point while pushing the lower half against the threaded calibration wheel I tighten the locking screw. I have found this method of use to be as accurate as my 2" Criterion as well as faster to use. In fact some time back I bored the .029" bore for my small steam engine with this head using a Micro 100 MBB-015050 carbide boring bar. The 4-40 threaded calibrated wheel was used to adjust the bar for the proper bore size. We all have our personal preferences and methods of doing what we wish to do including myself. Even though I would have designed the Sherline boring head slightly different, it has performed as well as any other head or method I have used. Jerry Kieffer ------- NOTE TO FILE: Now the thread is changing to a specific boring problem, but still using the last subject title. It eventually changes the title to "Line Boring in the Lathe". And you still wonder why archives are so hard to search :-? ------- Date: Sun, 02 Jan 2005 15:28:33 -0800 From: Alan Marconett Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Hi Marcus, List, I have a boring project! That is, I need to bore four (4) split bearing mounts (1/2" dia) in the entablature and outboard bearing mounts of my current Rectilinear steam engine project. Bronze bearings will be turned to fit these mounts. I posted a pix in the photos under "KM6VV engines". The entablature is the square ring in the center. The outboard bearing mounts can be seen in front of, and behind the entablature. The hole affair (pun intended) is elevated on 1/4" brass packing on the 5" x 6" bedplate. The entablature parts are split, so the the round center sections can be drilled. (The entablature and outboards will be up on eight 4" tall columns for the running engine). All four bearings MUST be in line! Now I know that I should do "line boring", and the pictured assembly looks like it will fit on the 4400 lathe. A 1/8" plate as a spacer underneath the bedplate is a little too much, so I'll have to mill 4 small spacers instead to the proper thickness. That gets the "splits" in the 4 bearing mounts to the proper height, and I can use a DTI to align the centerline to the long axis of the lathe. I know from reading the "Shop Wisdom of Rudy Kouhoupt" that I should make up a boring bar, and "bore between centers". Rudy's example was for boring 1" diameter or so; I need to start at about 3/8". Are you talking about something similar in your boring bar? Any suggestions on the job or boring bar? I think Jerry K. may have already done this operation, but on a smaller scale! Alan KM6VV ------- Date: Sun, 2 Jan 2005 19:32:29 -0500 From: "Jerry G" Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Alan, that job is screaming for a horizontal boring mill! I would attack it differently..... I would provide precise locating dowel pins for each of the four bearing mounts. Then bore them in the milling machine.... A master bar for lineup and you are in business... Regards, Jerry G (Glickstein) P.S. The setup for boring in the lathe would be time consuming, tricky and cumbersome..... ------- Date: Sun, 02 Jan 2005 17:30:09 -0800 From: Alan Marconett Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Hi Jerry, yeah, but Sherline hasn't made one yet! I was planning on boring the pieces in the mill, but the assembled basebed is too long to be clamped vertically. Next thought was to drill two pairs of holes in another, shorter block, so that a pair of pieces could be drilled/bored at a time in the mill. This block could be bolted up against an angle block and quite easily drilled in the mill. I bored each "half" of my "Tiny Tangye" horizontal mill steam engine this way! I don't have dowel pins in the design, but I do have 5-40 screws securing the ends of the parts. A 5-40 through a #30 (0.1285") clearance hole allows a little adjustment on assembly. I've noticed that things get really tight when trying to slide the 1/2" thick steam chest down to the cylinder block on studs of 1/8" drill rod threaded 5-40. The same clearance holes were used. That may work well enough for dowel pins! A 1/2" steel bar was going to be my "master bar". The setup in the lathe would be tricky, that's true. Probably why I haven't bored them yet! Alan KM6VV ------- Date: Sun, 02 Jan 2005 17:39:11 -0800 From: Alan Marconett Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! n2562001 wrote: > Allan. The bearing block alignment for this engine is not as critical > as you may think. Line boring four bearing blocks on top of eight > posts will not produce a straight line bore. (Ask me how I know) > I would suggest mounting all four bearing blocks on a plate next to > each other. From that point you can bore or drill and ream all four > at the same time. You will find that you will need to align all > four blocks by moving and shimming until alignment is achieved. And > maybe again a year from now. Jerry Kieffer Hi Jerry, yeah, I figured I couldn't get away boring them up on the "stilts" (3/8" columns). I currently have them bedded down on 1/4" packing on the basebed, so they're only about 5/8" above the plate. I can make a similar plate, with close-up spacing. I was trying to avoid shimming, just get buy with a little "adjusting" of the mounting bolts. But then, having the 8 columns will introduce their own alignment problems! Alan KM6VV ------- Date: Sun, 2 Jan 2005 20:48:54 -0500 From: "Jerry G" Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Another crazy idea from a wild and crazy guy (me). How about the Horizontal Milling Conversion P/N 6100? A guy like you should have no problem using that setup. Regards, Jerry G (Glickstein) P.s. I assume you know how to do line boring in the mill? ------- Date: Monday, January 03, 2005 2:24 PM From: Alan Marconett Subject: Re: [sherline] Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Hi Jerry, I've done line boring in the mill, or at least that's what I called it. ;>) I bored the two bearing blocks for one side of my Double "Tiny Tangye" horizontal mill steam engine, as I just mentioned to someone else. Key was to bolt the basebed of the engine up to a right angle bracket, so that the bearing blocks can be bored "in place". I looked at the Sherline "horizontal mill" kit (which I'd forgotten about), and really didn't see what I think of as a horizontal mill. Horizontal spindle all right, but no second support of a mandrel carrying cutters. My mill is already bolted to a 1" thick x 9" x 14" slab of aluminum, so I could just add a few more tapped holes in addition to the extra pair I have behind the normal mounting holes. I don't like the idea of cutting my Z axis support in half, it's too short as it is! I'm currently drawing up a jig, a 7" long x 1.5" wide x 1" thick bar of aluminum. A piece of scrap from a machine shop, it already had three counterbored holes through the width of the bar. I'll drill and tap holes to receive the 1/8" studs to take the new part blanks. While drawing it up, I realized that I could drill and tap a few more holes. Then bolt my tooling plate up to it at right angles to the X-axis ways, and I'd have a very useful right angle tooling plate! Alan KM6VV ------- Date: Mon, 3 Jan 2005 15:26:02 -0500 From: "Jerry G" Subject: Re: Re: Boring Head Inaccuracy! A 4-40 screw ?!?! Alan, you could make an outboard support for the cutter arbor and end up with something closer to a real horizontal mill. Regards, Jerry G (Glickstein) ------- Date: Mon, 03 Jan 2005 03:22:41 -0000 From: "implmex" Subject: Re: Line boring in the lathe Hi Alan: I had a good look at your photos. I'm impressed with what I see; you obviously know your way around machine tools, and your craftsmanship looks first class. I do have a couple of questions; please bear with me. First, do you have a means of reliably replacing the bearing mounts in exactly the same places once you take this assembly apart after the line boring operation? The reason I ask,is that the effort of line boring is not much value if your parts are free to change location after disassembly, and it's not obvious from the photo, how you've made provisions to re-establish alignment once it's disturbed. Second, is the diameter of the bushings critical? I assume not, since you've stated that you'll turn them to size after the boring is done. My experience with this operation is that it is a royal pain in the rear to get everything aligned if your expectation is to be within 0.001" or better in all respects. This is because the lathe is an awkward platform for making the setup, and you'll rely a lot on shims and rubber hammers, and DTI's to get there, or as close as your patience allows. The boring operation itself is not too bad, but there are some things that are unique to the setup between centers that create some awkwardness: First, if your cumulative bore length is 6" end to end, you need a 12 1/2" long bar with the cutter in the middle, to line bore this length, and if you envision the setup mounted on the lathe, you'll immediately see why this is so. Such a long skinny bar has a tendency to whip and deflect in the middle and the cross hole for the cutter doesn't help!! This means that you'll need to take light cuts, and you should choose a stiff bar material...remember, it's less than 1/2" diameter and LOOOONG. A mild steel or Leadloy lump will not likely do well here. The ejector pin cutoffs I favour for boring bars are typically much shorter than this... a toolmaker would be killed on the spot by his boss if he took a long pin and cut that much off it. Long pins are expensive, and I'm hesitant to recommend that you go out and buy a virgin pin just for this job. What makes ejector pin cutoffs so desirable is that they're made of a nice hard steel and are then nitrided and centerless ground. They're very smooth and straight; typically 0.0005" undersize from the nominal diameter, and 75 Rockwell on the surface. This glass hard skin seems to give them better stiffness than the equivalent toolsteel bar, but the skin is very thin, and can easily be removed in the places where you want to cross drill and tap for the toolbit and setscrew to hold it in. The steel underneath the skin is tough, but can still be tapped with care and a good quality tap in good condition.However, you're unlikely to find what you need in some toolroom cutoff bin, so we need an alternative. I think typewriter carriage guide bars might be hardened, or maybe the round slides that some printer heads run on. Both are worth a look as a possible alternative, but hard to get the tapped hole for the setscrew into. You can also get hardened linear rail stock or hydraulic cylinder shafting, but now you're into dollars and hassle again. With this length to diameter ratio, you may still get away with prehardened 4140...this is readily available and cheap, but I've never tried so I can't promise success. As a last resort, you could either harden a length of drillrod, or even try an unhardened length and see if you get away with it. Moving on to the toolbit, you need to grind a specific shape on it to have a good outcome. You want generous clearances and good side rake, but a very small nose radius and very little top rake. The reason is, that you want to avoid toolbit shapes that tend to deflect the bar either by pulling it into the work (too much top rake) or pushing it away from the job (too much tip radius and too little side rake). The actual geometry is going to have to be determined empirically, but I'd start with 15 degrees of side rake, zero top rake, and a tip radius of 0.003" max. Stone the radius onto the tool with a fine India stone and check it with a 10X magnifier. Your tool must be very sharp and very smoothly radiused...if you can scare up a fine Arkansas stone to lick over the edge you'll do better yet. Cuts should be very light...0.005" max per side, with as many spring cuts as it takes. You'll find right away, that this is going to be a tedious business if you've left too much stock on the bores...I'd get them as close as I dare to go as individual pieces before I did the final assembly and line boring operation. Watch the cutting process closely; at the first sign of chatter (Chatter is going to be your big enemy with this long floppy bar!!), drop your speed and increase your feedrate. If you wait until your bar is screaming blue murder, it will be extraordinarily difficult to get it cutting cleanly again...the toolbit will pick up the previous chattermarks and start vibrating again leading to more chatter. You'll also find that hitting your size is more difficult with this setup than it is with any other style of boring. One obvious problem is that the bar is always in the way of any measurements you might wish to make, and if you pull the bar out to measure, it'll cut a slightly different size when you put it back in. So don't plan to hit a nominal size...turn your bushings to suit what you get if there's any way you can. If you can't get around a requirement for a specific size, you can always leave a tiny bit (0.003" max) in the bore and line ream to final size. Once the holes are all co-linear and close to size, the reamer will follow them nicely, but you must watch the entry of the reamer into each successive journal to be absolutely sure the reamer doesn't pick up a chip as it's starting its cut, and get forced out of line. It's worth stopping the reamer and cleaning its tip before the reamer touches the start of each journal. Ream with slow speed and very sloppy with lube. You'll get decent geometry, (including co-linearity) decent size control and a crappy finish. That's all I can think of for now, Alan. Hope it helps and good luck with it. Let us know how you make out and please post pics!! Cheers Marcus ------- Date: Mon, 3 Jan 2005 02:05:28 -0500 From: "Jerry G" Subject: Re: Re: line boring in the lathe Alan, (Marcus) Line boring in the lathe is tricky, cumbersome, and the results generally unpredictable. Too many factors to control. I think the time would be better spent with locating each journal for repeatability and boring each one individually in the milling machine. That is where interchangeability and toolmaking come into play....:) Suppose after a tedious setup and successful completion somehow the assembly is subjected to shock and, or accident? Individual components held only by screws is not the answer... That is why individual die parts are doweled into place on a sturdy die shoe.... Also, you can farm out the end result for honing if you are concerned with a superior finish... and sizing... All that Marcus outlines is classical boring on the lathe. I have done it, never liked it... Provision for alignment AFTER boring is the way to go here, in my opinion. Regards, Jerry G (Glickstein) ------- Date: Mon, 03 Jan 2005 12:34:08 -0800 From: Alan Marconett Subject: Re: Re: line boring in the lathe Hi Jerry, I can see that dowel pins would be better, but I can't really modify the entablature design to incorporate them. I did have a thought, I can make the studs that go through the entablature and thread into the 4" high columns (3/8" diameter, tapered) not threaded where they go through the entablature, this will close up the tolerances, just like I do on the steam chest. The bedplate is symmetrical, and the mounting holes in it should be quite accurate. At first, I was considering clamping it one way to bore two of the blocks, then flipping it around 180 degrees and boring the other two blocks. Probably would have meant disaster! I've since figured out that I should bore the same face of ALL the blocks, and will thus not have that problem. That, in combination with the jig, I think will do the job. With the X and Y-axis secured, I should be able to get fairly consistent bolting of the stock. We'll see. Alan KM6VV ------- Date: Mon, 03 Jan 2005 12:11:09 -0800 From: Alan Marconett Subject: Re: Re: Line boring in the lathe Hi Marcus, thanks for the excellent description! And also the kind words! You're right, I don't have a way to accurately replace the bearing mounts after things are re-assembled. The bearings can be turned to fit, that's not a problem, and I plan to just use a piece of 9/32" drill rod (as straight as I can find) to align the mounts and their installed bearings after assembly. According to Jerry K, the alignment doesn't have to be that close for this engine, so I may have some breathing room. There is actually two separate crank throws, one in the front pair, and one in the rear pair of bearings. The rectilinear motion of this engine is quite interesting, and unique! At this point, I'm inclined to mill the bearing mounts in the mill, on the jig I've just posted about. This way, my "bore" is less then 1" deep, and should be far simpler. Yes, I'm going to use the Sherline boring tool, although I'd LOVE to have the Criterion DBL-152 boring head! Probably WAY to expensive. I've been getting by with the Sherline boring head, and now that I know, I'll clean up the ends of the screws, and see if that helps. I DO have a 1.125" diameter x 1.875" cylinder to bore, so I may try boring "between centers" on that part. It's a heavy lump of brass! Currently a 2.5" diameter x 3" rod. Probably a little too much to chuck up in the 4-jaw chuck. :>| What are ejector pins? Something for mold making? I bought some 1013 "make a pin" stock from MSC, but it's Zinc coated, and is not what I think you're talking about! (not that big diameters, either). I DO have some steel rod from various printers I have disassembled, but the stuff is usually hard! I haven't done much with it. I considered buying a 1/2" reamer, but $45 for a U.S. made tool for a single job is a bit much! Best regards, Alan KM6VV ------- Date: Mon, 03 Jan 2005 22:22:22 -0000 From: "n2562001" Subject: Re: Line boring in the lathe Alan wrote > According to Jerry K, the alignment doesn't have to be that > close for this engine, so I may have some breathing room here. Alan, I would like to clarify my statement. Normal bearing fit will not be workable on this engine. If it was possible to do a line bore with the four bearings on the eight posts for proper alignment and fit, the engine would not run most of the time. Because of the design of this engine the alignment will change with temperature change and lock up the cranks with normal bearing fit. Friction will be your biggest enemy. For a nice running engine you will be lucky to have main bearing fits closer than .002"-.003". I would suggest that you construct the bearing blocks in such a way that you can easily adjust alignment in all directions. You will need this adjustment to compensate for the slightest error on other parts of the engine. Jerry Kieffer ------- Date: Tue, 04 Jan 2005 03:07:58 -0000 From: "implmex" Subject: Re: Line boring in the lathe Hi Alan: Having looked at all the information that's been revealed in this thread, I definitely agree with your notion to bore them as individual pairs and then set them up using a shaft to align them. It will make your machining tasks so much easier and faster. So much for the dissertation on the evils of line boring...oh well, maybe a task will come up for which you have no other choice and then you can play with it, and see just why everyone who's done it swears at it!! To answer your question about ejector pins...you are correct, they are plastic injection mold components, and their function, as the name implies, is to push the molded part out of the mold cavity or off the mold core. They come in standard lengths and are chopped to the required length using an abrasive cutoff wheel, then precision ground to very close length tolerances. The bits that are left over after chopping them off are waste to a toolroom, but absolute gold to a hobbyist. With regard to the inadequacies of the Sherline boring head; I wouldn't give up on it quite yet, especially since you've already bought and paid for it. The principal complaints with this head seem to be that the adjustment screw only moves the slide one way, and doesn't have a very reliable means to move the slide in small increments. These problems are all easily surmountable. Use a dial indicator with a flat anvil and set it up on the tip of the boring tool. Loosen the clamp screw that clamps the slide and then snug it up again until it just allows you to push the slide by hand. Memorize how much torque that took. Now you can pick up the tool tip with the clock, swing the tool tip around a bit to find the high point, (that's why you've got a flat anvil on the clock). Zero the clock and then set the depth of cut while watching the clock instead of the hokey graduations on the boring head. Now snug up the clamp screw and check to see if the tool tip moved. Sometimes it does, even on a Criterion head. Then carve out your bore. Not surprisingly it's more accurate to do it this way than relying on the boring head screw (even with high end boring heads), because you measure how far the tip moved directly, rather than relying on the accuracy of all the intermediate components. I've set boring tool tips directly this way for years now, and I can hit a bore size within 0.0005" no sweat every time. Play with it a bit before you abandon the Sherline tool...it can be made to work just fine. Cheers Marcus ------- Date: Mon, 3 Jan 2005 23:23:46 -0500 From: "Jerry G" Subject: Re: Re: Line boring in the lathe Marcus, just to clarify something..... If I need to work close for a bore, I ALWAYS control the movement of the boring bar with a DTI...... But, the final criteria is the results..... A boring head can creep under the clamping pressure.. Then, we have the famous deflection, and "spring cuts" required to help the boring bar relax....To get to the right place requires more than the ability to control the location of the cutting tip. It requires experience with the material you are working with... The choice of the right speed and feeds. How the bore is measured is equally, and even more stringent than getting there. Honing is cool, measuring with an Intrimik is cool, gaging with a pin or plug gage, (Go -No Go) is also cool. So, you point out the old adage..."It is a poor workman who blames his tools"... and Jerry G says "A good workman can surmount any tool deficiency, even if he has to build a new one"!. Regards, Jerry G (Glickstein) ------- Date: Mon, 03 Jan 2005 21:25:30 -0800 From: Alan Marconett Subject: Re: Re: Line boring in the lathe Hi Jerry, sorry if I misquoted you! It sounds like the engine bearings must run loose, and that getting it to run is a real chore. :>| I don't know how I'm going to be able to adjust in all directions, I could make the bearings loose in their blocks, and secure them with LocTite when they are in position? I guess we'll see how it all goes together! Alan KM6VV ------- Date: Tue, 04 Jan 2005 16:32:09 -0000 From: "n2562001" Subject: Re: Line boring in the lathe Alan, you didn`t misquote me, my statement wasn`t very clear as usual. You can shim for up and down. The mounting bolt holes may need to be enlarged for other adjustments. Not a normal way of doing things but this is not a normal engine. It will be no problem at all to get the engine running as long as everything is loose enough. As you assemble and run the engine you will understand why it was not a successful design. Jerry Kieffer ------- Date: Mon, 03 Jan 2005 21:09:41 -0800 From: Alan Marconett Subject: Line Boring Entablature Hi to the list, I've just finished making a jig to hold a pair of parts to be line bored (total 4 bearing blocks). I also got the idea to tap a few more 10-32 holes, and add a few holes to my tooling plate (counter sunk). I've now got a nice right angle tooling plate! Oh, and the jig worked great to drill and bore the bearing blocks for the Rectilinear steam engine I'm building. (I need an 'R' word for the engine's name.) I've posted pix under KM6VV engines, in case anyone is interested in how to do a task like this (or at least one way). I was able to bolt up the parts, and get a snug fit for a 1/2" 12L14 steel bar, so I'm happy! Alan KM6VV ------- Date: Tue, 04 Jan 2005 10:21:53 -0800 From: Alan Marconett Subject: Re: Re: Line boring in the lathe Hi Marcus, I'll try a lathe "line bore" some other time! I've got my four split bearing blocks bored, and all is well! (pix posted in KM6VV Engines) Those pins sound like good stuff to have. Too bad I'm not "working in the industry". I'm fine on the Sherline boring head, despite it's limitations, and I must have an OLD one (20 years?), because I don't have a little dial on mine. The Cryterion boring head sounds good, but I'll bet it's expensive. Building my own is a possibility, I have a dovetail cutter. I see where Jerry G's has a disk on the screw that is captured to cause motion in both directions. But it doesn't have a fine thread, does it? Might be a good future project! I have an old "Last Word" DTI, and a Mitutoyo .0001" - .050" plunger dial indicator. Used, and was sticking, but I think I've got it working now. Big flat plunger, and 2"+ dial, so it's a little big for use around the Sherline. If I understand you, the dial plunger must be positioned near the hole, and kept there, even while boring? I have a magnetic base, but that won't be of much use. I'm still puzzling how to bore and keep the plunger out of the way. Best regards, Alan, KM6VV ------- Date: Tue, 4 Jan 2005 19:29:35 -0800 From: "Marcus and Eva" Subject: Re: Re: Line boring in the lathe Hi Alan: You need to remove the clock each time you start the boring head. On a Sherline that means making up a mounting plate out of mild steel and bolting it to the table somewhere beside the job. Then you can stick a mag base to the mild steel plate and remove it easily. You'll be resetting the zero on the clock after every cutting cycle, but that's just a matter of spinning the bezel of the clock, after you've rotated the cutter to find the high point. I normally do this only for the last cuts...my rough and dirty technique is to move the table over as much as my next depth of cut and then drop the bar into the top of the hole and push the tip of the cutter against the bore sidewall. Then I raise the bar back out of the hole and recenter it over the hole. I can now take my next pass. Repeat as needed until you are within 0.010" or so. Then start clocking for your last cuts. That's the method I developed largely because I do most of my boring without a boring head...just a plain boring bar, so I have no other convenient means to measure the depth of cut. Oddly enough, even though this way sounds dreadfully cumbersome, I can bore holes a lot faster than anyone who's running a boring head. That's because I can run a carbide bit and spin the machine way up. I'll finish bore in P20 steel at 2200 RPM or so for a 1" hole using a carbide tip. My competition is crawling along at 250 RPM and getting a poor hole finish from the low surface speed and the machine is humping all over the floor from the eccentric mass. So my 0.005" cut per turn gets me through the bore way faster than his 0.005" cut per turn...ten times faster!! In fact, if you look at many of the production boring tools, they operate on the same principle, but they use a threaded cartridge that houses the cutter. Same low eccentric mass, but adjustable with a dial. I don't like them because they are hideously expensive and very vulnerable sitting right at the business end where all the hot abrasive chips can beat them to pieces (expensive pieces!!) My way is dirt simple...not much to go wrong, and as Jerry G will surely corroborate, if it can possibly be broken...some bonehead will break it, and there is an inverse relationship between its survival and its sticker price. Cheers Marcus ------- Date: Wed, 15 Mar 2006 08:04:02 -0600 From: "Leo Reed" Subject: RE: Boring Bar Question [atlas_craftsman] > From: mmmmmbikes > To: > Date: 3/14/2006 8:46:55 PM > Another beginners question: What is the proper way to mount a round > boring bar in a rocker style toolpost? Is a special holder required or > can it go directly into the post as long as the width is good? I've > been looking at the MSC catalog and am once again overwhelmed at the > selection. At some point I will need to bore a 2in dia. hole 2-1/2in > deep in a piece of 6061-T6 aluminum and I'm thinking that a hardened > steel bar with 3/8 shank and HSS cutter would do the trick? Thanks > Mike G, who is finally getting around to doing what I wanted to do 30 > years ago before life got in the way Mike, I've used the lantern style tool post to mount various boring tools, bars, etc. My method is to flip the concave circle washer over, not using the round wedge. I used spacers to lift the tool point to the center line of the lathe. I drilled a piece of aluminum with a 3/8" drill. I then cut it in half. I use it to rest the bottom of the 3/8" shank of the bar. I use the other half to enclose the top of the shank, so that the screw presses on it. I have now taken a 1.6" square block of aluminum and drilled it to accept a 3/8" and a 1/4" boring bar. I have the kind that uses round tool bits. I mount this on the compound in place of the lantern style tool post. Much more solid. Leo (pearland, tx) ------- Date: Thu, 16 Mar 2006 20:17:23 -0800 (PST) From: Matt Baraga Subject: Re: How to bore very small holes? [taigtools] eferg2001 wrote: >>I need to bore a blank A2Z Taig end mill holder for a custom step drill that has a 2.5 mm (0.098") shank. This will be used on my Taig CNC mill. I have a LatheMaster 8x14 lathe with a 5C collet chuck. It can hold the blank end mill holder from the inside by screwing it onto a spare Taig spindle shaft, which in turn is held in the 5c collet. However, I don't think drilling and reaming with a drill chuck in the tailstock is going to be precise enough to give me an accurate 2.5mm bore. I think a micro boring bar is the best solution here. Any idea where I can find one small enough? Other ideas? Ed << www.mscdirect.com ------- Date: Fri, 17 Mar 2006 04:51:47 -0000 From: "n2562001" Subject: Re: How to bore very small holes? Ed: Miniature boring bars are available from Micro-100 and others for the hole size you need. If you need an accurate hole centered in the holder I think you will find your intended lathe setup less than desirable. I would suggest mounting the holder with a slightly smaller than needed center hole on the mill you plan to use. Then mount the boring bar in the vertical position using your mill vise. This will allow you to bore the drill shank hole with the mill by moving the holder down over the boring bar. The result will be about as accurately centered as you're going to get. Jerry Kieffer ------- Date: Thu, 16 Mar 2006 21:15:46 -0800 From: "Vlad Krupin" Subject: Re: How to bore very small holes? 2.5 mm is awfully small compared to the length of the hole you need to bore out. I have ground a small boring bar to bore out blank arbors. It can bore holes just over an inch deep, and is about twice the size of what you need. Yet it flexes *a lot*. It hasn't snapped on me yet, but I do not think I could go much thinner... I am not an expert in tooling, but somehow it seems that creating a boring bar that fits < .1" holes and can bore holes 1" deep is challenging. For starters, that's a ratio of more than 10:1! If you were to make a bar like that, you'd have to keep it always razor sharp, take very, very fine cuts, and you will still have a hard time dissipating heat. This does not sound like something you could use in a production environment, yet people do make small deep precise holes all the time. I've been wondering myself for quite some time how that's done, so if someone knows, I'd love to hear from you! Vlad ------- Date: Fri, 17 Mar 2006 09:13:28 -0600 From: "Bad Brad" Subject: Re: How to bore very small holes? Vlad: Why would it need to be bored 1" deep? Seems like overkill. I would only bore 3/8 inch, the hole would be plenty deep without compromising rigidity. (It will be used for a step drill which has minimal side loading while in use anyway.) Jerry K's advice will yield the most concentric bore. If you want concentricity when using aftermarket mill cutter arbors, the best bet is to buy them undersized and then bore them right on the mill spindle. I'm sure this would solve a lot of the issues you read about on the news groups concerning the run-out on aftermarket mill cutter arbors. FBA ------- Date: Thu, 16 Mar 2006 21:29:13 -0800 (PST) From: Matt Baraga Subject: Re: How to bore very small holes? Cut a small hole and bore it to full size. Use rigid setups. No noise -- not even a sneeze by the machine. Make sure the temperature inside your case doesn't go + 1 degree F. Make sure you've isolated all vibration. Lastly use high quality tools at the right speed and feed. ------- Date: Sat, 18 Mar 2006 19:54:03 -0800 From: "Vlad Krupin" Subject: Re: How to bore very small holes? > Why would it need to be bored 1" deep? Seems like overkill.... (It will > be used for a step drill which has minimal side loading while in > use anyway). Jerry Ks advice will yield the most concentric bore. You are right. I guess, it may be an overkill to have a full 1" of contact, especially for a step-drill. That should make the boring task quite a bit more manageable. > If you want concentricity when using aftermarket mill cutter arbors > the best bet is to buy them undersized and then bore them right > on the mill spindle. The idea of boring holders out on the spindle where they will be used is great. I hope that will work for other people who try that. I've tried to do that, several times, and finally gave up. Somehow I get an awful lot of chatter doing so, and can't pinpoint the source of the problem. Oh, well, no big deal. I found a (somewhat tedious) workaround. Hope others have better luck :). ------- Date: Mon, 20 Mar 2006 08:45:30 -0600 From: "Bad Brad" Subject: Re: How to bore very small holes? Vlad: The mill table must be locked in both axis. The boring tool has to be ground with the correct relief and the cutting edge must be on center. Light cuts with lots of cutting fluid of some sort is also required. I would also buy arbors as close to size so the amount of material is minimal. Still have chatter after following the above advice? Reduce speed and increase feed. I often hand turn the spindle by hand on jobs where I just can't get rid of the chatter. I hope this info helps. FBA ------- NOTE TO FILE: The following thread "Lathe recommendation" has been divided into 2 parts. The Boring how-to aspects are recorded here in the Boring file. The choice of lathe rapidly became a very heated conversation and those messages are reported in the Lathe Comparisons file -- March 2006. ------- Date: Mon, 20 Mar 2006 16:19:10 -0000 From: "Robert House" Subject: Lathe recommendation [LittleEngines] Hello Group, I don't like to start out with a question, but I don't have any experience to share with the group. I retired in 1999 and since then I have increased my time spent restoring old trailbikes, mostly Honda. These bikes are over 40 years old now. (Doesn't seem possible, does it?) It is costing me about $60 to have a cylinder bored and honed. I can do the honing myself, but really need the boring done by a pro. Can someone recommend a method for boring an Approx. 2 inch cylinder? I have seen small lathes at the Harbor Freight store for about $500. I understand the quality issue with their Chinese stuff, but would that suffice as a machine for boring cylinders? I would like to cut new valve seats also, up to 1-1/4 inch. I sure do appreciate any help with this, since I have about 40 Honda's in various condition from almost new to anchor material. I think a lathe or milling machine would be a handy addition to my shop because I am always coming up with ideas. Robert Chesapeake City, Md. ------- Date: Mon, 20 Mar 2006 11:58:17 -0500 From: Donald Qualls Subject: Re: Lathe recommendation If that's a sleeve you're boring, and you can press it out of the finned cylinder jug, then the 7x10 (or preferably one of the many brands of 7x12 that are identical save only bed length) will do the job nicely, given some care in setup and decent tooling. I have a 7x12, and it's quite happy with a 4" 4-jaw chuck, which is capable of holding work up to about 4" diameter (though it's difficult to turn the exterior of such large work because of a limitation in the cross slide -- something I hope to correct with a collar extension at some point). The slightly larger 9x20 will handle bigger work, but is a less versatile machine out of the crate (no tumbler reverse, nor reversible spindle; not even a variable speed motor, instead using belts to vary spindle speed). If diameter isn't an issue but even 12" between centers is restrictive, Micro-Mark sells 7x14 version, upgraded with true inch cross and compound screws, as well as a bunch of nice accessories (but at a price premium compared to the basic 7x12). You might be able to swing the entire cylinder on a 7 inch lathe; I don't recall how big the cylinder fins are on these (I know it's smaller than the head, which houses the valves and seats); doesn't seem a 90 cc engine would have that big a cylinder, though. For valve seats, you really only need a drill press and piloted seat cutter with depth stop, plus suitable work holding fixtures, though a milling machine is certainly more versatile (you can mill heads and cylinders flat, etc.) ------- Date: Mon, 20 Mar 2006 10:46:25 -0800 From: "Tom Faragher" Subject: Re: Lathe recommendation You would be better off spending the $500 on a used cylinder boring machine. The setup required to properly bore a cylinder must be exactly straight and extremely rigid to avoid tool chatter. The glazed surface of a worn cylinder bore is very hard and the depth of cut will vary due to taper in the worn hole. A small Chinese lathe is definitely not up to the job. Cutting valve seats is also a specialized job requiring the proper tools. The seat cutter should ride on a pilot in the valve guide. Regards Tom Faragher ------- Date: Tue, 21 Mar 2006 00:20:37 -0500 From: "Carl Corbeau" Subject: Re: Lathe recommendation Tom, I agree with your recommendations, but if I had no boring machine I think I would bore it on my Bridgeport mill before I would try it on a lathe. Carl ------- Date: Tue, 21 Mar 2006 08:21:52 -0800 From: "Alan Marconett" Subject: RE: Lathe recommendation [LittleEngines] > If the lathe has enough "Z" axis travel to handle the needed bore depth > and a boring bar length to do it, it will perform the job just as well > as a mill or boring machine. JWE Long Beach, CA Hi JWE, I agree, maybe even better? The stock can be supported more (it's laying down on the carriage), and a boring bar can be ran "between centers". Alan KM6VV ------- Date: Tue, 21 Mar 2006 16:43:12 +0000 From: j.w.earlyx~xxatt.net Subject: RE: Lathe recommendation Alan: That is true if someone has or makes a traveling head boring bar with an adjustable tool holder. I have seen several drawings for this type of boring bar, but I have yet to see one that works really good. Even most of the factory ones are marginal in the smaller sizes. Using a fixed one between centers still requires a fair amount of room between centers. A decent traveling cutter head boring bar is a much needed design for the home user and something I have looked for a long time with small success. JWE Long Beach, CA "Be wary of strong drink. It can make you shoot at tax collectors... and miss." Robert A. Heinlein ------- Date: Tue, 21 Mar 2006 11:57:20 -0500 From: "Carl Corbeau" Subject: Re: Lathe recommendation If you insist on doing it in a lathe, by all means do it this way. Is this discussion going to continue to be about which lathe one shouldn't use, or about how to actually do the job? Mounting in a chuck is not on. The part would have to be held by the skirt. This would take it out of round. It cannot be set fully into the chuck, as the cutter has to pass clean through, leaving the outboard even more tenuous. If it was just a sleeve you could use a steady, but you still have the problem of skirt distortion. Carl ------- Date: Tue, 21 Mar 2006 17:19:45 +0000 From: j.w.earlyx~xxatt.net Subject: Re: Lathe recommendation Carl: Then I would suggest some form of between centers bar and mounting the work on the saddle. If you use a fixed head boring bar you will need enough distance between centers for the boring bar and the cylinder. If you have a moving head bar similar in function to a cylinder boring machine than you only need slightly more distance than the length of the cylinder and the boring head on both ends. JWE Long Beach, CA ------- Date: Tue, 21 Mar 2006 10:57:24 -0600 (CST) From: Mike Delany Subject: Re: Lathe recommendation I helped a neighbor a couple of years ago bore out a small two cycle cylinder by making a jig that mimiced the case flange that the cylinder bolted to. We made it out of a piece of three quarter hot rolled steel and then torqued the jug down to it. We grabbed the jig in the four jaw on his lathe and dialed it in with a couple of indicators. We used a regular boring bar and the power feed to bore it using about a dozen light cuts. We then used an overgrown brake hone to do the final finish. The hole came out the right size with a good finish so I guess that it was a success. Mike http://www.p1800s.com ------- Date: Tue, 21 Mar 2006 15:12:00 -0500 From: "Carl Corbeau" Subject: Re: Lathe recommendation Mike: If I had to do it on a lathe, I would use your method. The same idea would work on a face plate, as well. Carl ------- Date: Tue, 21 Mar 2006 14:01:18 -0600 (CST) From: Mike Delany Subject: Re: Lathe recommendation We thought about using a face plate, but the bottom of the liner was not totally square. Mike http://www.p1800s.com ------- Date: Tue, 21 Mar 2006 13:15:16 -0800 From: "Alan Marconett" Subject: RE: Lathe recommendation Dirk wrote: > Hello JWE, Do you still have access to those drawings? If you do, > could you send them to me? HI JWE, Dirk, I'd be interested as well. I don't think I have a good idea of what a traveling head boring bar would be. Probably too big for a Sherline? ;>) Alan KM6VV ------- Date: Tue, 21 Mar 2006 21:41:56 +0000 From: j.w.earlyx~xxatt.net Subject: RE: Lathe recommendation Alan: It could be made to any size; it is just the smaller it is, the more flexable it would be -- requiring smaller cuts. I will dig up the location. JWE ------- Date: Wed, 22 Mar 2006 14:25:05 +0000 From: j.w.earlyx~xxatt.net Subject: Re: Lathe recommendation Dirk: I found the boring bar articles already posted here: http://groups.yahoo.com/group/mwlatheideas/files/NeatIdeas/ There is a good one illustrating how a traveling head system works and another illustrating how the fixed bar and moving work on the carriage works. For the traveling head type you do need more room in the bore for the tooling than the other does. JWE Long Beach, CA ------- Date: Tue, 21 Mar 2006 19:48:24 -0500 From: "Jim Dunmyer" Subject: Re: Lathe recommendation James, I've bored cylinders on both machines, a Bridgeport and a 19" lathe. If the mill has enough travel on the quill (5" on a B'Port), it'll do a better, straighter job than the lathe. It's highly likely that the lathe will have enough wear that you'll get a taper. At least, that's my experience. Jim lower SE Michigan, USA http://www.oldengine.org/members/jdunmyer ------- From: "Andrew Carlisle" acarlislex~xxidelix.com Date: Thu May 18, 2006 2:00pm(PDT) Subject: Acceptable runout and wobble on a boring head? [taigtools] I'm looking for a little advice on a small boring head and adapter I purchased to use with my Taig. When mounted on my Taig spindle, the boring head has over 0.010 runout as measured at the base of the head. The runout is noticeably worse at the tailstock end of the boring head because of a pronounced wobble. I don't recall the actual figures at the moment. Do you think the head is useable with these shortcomings? I'd certainly like the unit to run straighter, but the vendor has suggested there is no *functional* issue, only cosmetic. The item in question was an inexpensive Chinese product. However, I had expected a little better. Your thoughts and opinions would be appreciated. Andrew ------- From: "Nicholas Carter and Felice Luftschein" felicex~xxcasco.net Date: Thu May 18, 2006 2:21pm(PDT) Subject: Re: Acceptable runout and wobble on a boring head? Given that you have the runout of the adapter plus the runout of the head, I'm not surprised at .010... You could try truing the adapter face, and the back face of the boring head and see if it helps. Then again because the boring head is a single point tool, the only negatives are a slight inaccuracy in the feed vs. the screw feed graduations, and vibration from the wobble. Are you running it with the stock motor, or a variable speed motor? I found it very hard to do boring at the stock lowest Taig speeds. See our homepage at www.cartertools.com/nfhome.html ------- From: "Andrew Carlisle" acarlislex~xxidelix.com Date: Thu May 18, 2006 2:49pm(PDT) Subject: Re: Acceptable runout and wobble on a boring head? The idea of having a go at truing up the parts had occurred to me. I thought I'd get some feedback here first, before I started in on modifications which would rule out returning the items for a refund. I have a variable speed treadmill motor on the Taig. With that set-up, and a makeshift boring head rigged with a boring tool holder mounted to a faceplate, I've managed okay in the past. Nothing high speed is possible, of course. But it was due to the success of my jury-rigged boring head that I decided to try the Chinese version of the "real" thing. Cheers, Andrew ------- From: "Nicholas Carter and Felice Luftschein" felicex~xxcasco.net Date: Thu May 18, 2006 3:54pm(PDT) Subject: Re: Acceptable runout and wobble on a boring head? If you can find one of the small Flynn or Criterion boring heads on Ebay, you will be much happier. See our homepage at www.cartertools.com/nfhome.html ------- From: "kwolson2002" kwayneolsonx~xxhotmail.com Date: Fri May 19, 2006 2:04pm(PDT) Subject: Re: Acceptable runout and wobble on a boring head? > How does one go about mounting a Criterion boring head on the Taig? > The Criterions I saw on Ebay seem to have an intergral 1" shaft. Some of these have a 7/8-20 internal thread so that you can interchange arbors (say #3 Morse and R8). LittleMachineShop sells an adapter that is threaded 3/4-16 for the TAIG (or Sherline) spindle nose and has the external 7/8-20 to thread into a boring head, but you could probably make your own, too. I am monkeying with the design for a boring head arbor for my Gorton mill, which has the old GTM taper. Kevin ------- How to bore these holes? [atlas_craftsman] Posted by: "Paul R. Wisner" pwisnerx~xxplanetkc.com Date: Thu Jul 6, 2006 10:06 am (PDT) I have a 12x24 with 6" 3 and 4 jaw chucks, faceplate, lantern tool post, right and left tool holders. I don't know how to cut 2" holes in flat 5/8" aluminum plate. See picture at http://www.whcinc.com/images/Plate02.JPG If I can come up with the right hardware I will attach it to the faceplate with spacers to allow for cutting clear thru. Can you describe how this is done with the tools I have? Don't have any kind of boring bar. Cut from center outward? How would you grind the tool for this? Paul ------- Re: How to bore these holes? Posted by: "Jon Elson" elsonx~xxpico-systems.com Date: Thu Jul 6, 2006 11:20 am (PDT) Mount the plate to the faceplate, and center using a tool as a reference point, either against a center mark for the hole, or the OD mark I can see in the photo. You may need to use C clamps or other trickery to clamp the plate without drilling holes where you don't want them. Once the plate is mounted and centered correctly, you drill the largest hole you can in the plate. Silver & Deming drills will drill holes larger than the max your drill chuck will hold. Or, if you can find some Morse taper drills, you can drill up to about 1" starting hole. The lantern toolpost is not very good at holding boring bars, but you are making a shallow hole, so a left-cutting lathe tool will do. You may need to elevate the cutter quite a bit above the centerline to keep the bottom of the cutter from dragging on the side of the hole. Now, just plunge the tool into the hole, opening it up maybe as much as .050" per pass. Watch for dragging of some part of the tool or holder, and adjust height and outward steps to avoid that. Yes, cutting from the drilled hole outward is the way to go. If you were doing a 6" hole, then maybe trying to trepan out the slug would be worth the effort, but probably not here. A trepanning tool for a 2" ID would need to have a lot of curve in the bottom support so it could reach 5/8" into the groove and still be strong enough to cupport the cutting edge. The grinding doesn't need to be particularly special. Just make sure it can cut along the ID of the hole without dragging. Use shims (tool blanks) to elevate the cutter in the lantern post as much as you can, so you don't have to angle it up too much. Or, you can make a special tool that has a LOT of relief on the left edge, so it can go in the 1/2" or whatever starting hole without too much trouble. You can then set this tool on centerline after the first couple passes. Jon ------- Re: How to bore these holes? Posted by: "Dave Mucha" dave_muchax~xxyahoo.com Date: Thu Jul 6, 2006 11:38 am (PDT) Simple answer is to buy a hole saw and do it on the drill press. Another is to buy some 1/4" HSS or Cobalt bits and make your own very short boring bar. Another is to buy a boring bar at Enco for less than $10.00. Don't forget to buy bits too. I have a 1/4" HSS bit that is heavily ground so I can use it to bore about 1" into a 3/8 hole. Look at the cobalt boring tools and just make one by hand. Also, you could take a hunk of steel that will fit in the tool post and then file a notch to hold a tool bit, lock it with a couple set screws. Make your own boring bar. Dave ------- Re: How to bore these holes? Posted by: "EARL BOWER" earl.bower1x~xxverizon.net Date: Thu Jul 6, 2006 12:22 pm (PDT) The way I was shown by one of the machinists where I used to work (back in the 70's) is to do the following. Carefully layout the centers that you want. Then center drill them deep enough that you can use your center in the tailstock. Bring up tailstock to center hole. Clamp in place on faceplate. Drill and bore out the size you want. Repeat the above for the next hole (if you want two or more). Earl ------- Re: How to bore these holes? Posted by: "jmartin957x~xxaol.com" Date: Thu Jul 6, 2006 1:30 pm (PDT) There are actually several different concerns here. I am assuming that your lathe is big enough to swing the plate without interference. ACCURACY OF LOCATION The most accurate way to locate the holes would be with toolmaker's buttons, which could get you to as accurate as your micrometer, calipers and dial test indicator can measure. If you don't need them that accurate, prick punch the centers and zero the punch marks with a wiggler. Or drill starting holes on a drill press and clock them in with a dial test indicator. If you don't need even that level of accuracy, use the tailstock center to align a punch mark or a drilled starting hole. WORKHOLDING If your four jaw chuck is large enough to hold the workpiece in the proper location, it's the best method to use - the jaw steps will make packing blocks unnecessary, and the jaw adjustments will allow you to center the bores. If you have to use your faceplate, you'll need packing blocks and strap clamps. If some of the holes already in the plate are in the right places, you may be able to use through bolts and washers in place of strap clamps, but that would be unusually lucky. BORING TOOL 5/8" isn't very deep, so if you don't have a boring bar you can use a left cutting tool bit. First, open up the hole with the largest drill bit you have. Then, a left cutting bit ground with lots of side clearance, cutting from the center out. You'll need more clearance towards the center, so if it's OK there, it will be fine at the outside. Those roughing cuts can be facing cuts or boring cuts - whichever seem to cut best with your tool bit. When it's close to full diameter, take a couple of boring cuts, measure, and set the cross slide for the final boring cut. Most aluminums cut well, but some are real gummy. Kerosene or WD40 should help. You've got a lot of material to remove before the final 2" bore. Use that time to see how your tool works, and how to get a good finish from it. John Martin ------- How to bore these holes? Posted by: "Frank Perdicaro" frankx~xxdsea.com Date: Fri Jul 7, 2006 11:15 am (PDT) There are some practical approaches and tricks to cutting big holes in aluminum. I have done quite a bit of it, from 1/4" plate up to 1" plate. First, use hole saws. I cut up to 4" holes with Lenox bimetalic hole saws. When using a hole saw, be SURE to make some "vent holes" for the chips. Drill holes so the inside of the holesaw cut will be tangent to the outside of the vent hole. Typically I use 1/2" holes. Second, use air. Use shop air to blow chips away. Lots of it. Third, use WD40 as a lube. Just spray it into the cut as fast as you can get it to come out of the can. Fourth, cut fast. Typically I run my machines at the fastest setting! There is no upper limit to the speed with which you can cut 6061T6 aluminum. With shop air, WD40, new saws and high speed cut you will take 20 seconds to get that hole in 5/8" plate. If you want, clean up the cut with a single pass with a simple cutter. With a 2" hole you do not need a special boring bar. One trick I use to make this sort of work have a nicer finish is to use a 1/8" carbide round-over wood bit in a router to finish the holes and outside edges. Spray all with WD40, then just route as if it was wood. Works great. Fast, too. ------- Re: How to bore these holes? Posted by: "n8as1x~xxaol.com" n8as1x~xxaol.com Date: Fri Jul 7, 2006 6:21 pm (PDT) In a message dated 7/7/2006, dave_muchax~xxyahoo.com writes: > Great idea on allen wrench as a boring bar, I'll be doing that. watch ur speeds ...allen wrench not Hi Speed...cut the SFM in 1/2. best wishes docn8as ------- Re: How to bore these holes? Posted by: "xlch58x~xxswbell.net" xlch58x~xxswbell.net Date: Fri Jul 7, 2006 7:16 pm (PDT) Jon Elson wrote: >If you need accurately-placed, accurately-sized holes, you can't do it >with a hole saw. For instance, think of the bearings that would go on >opposite ends of a pair of shafts that will be geared together. You >need the shafts to be parallel at the correct spacing, and the holes >need to be within a thousandth of an inch or so to hold the bearings >securely. No way you can do this with a hole saw. Even if you use the >hole saw to rough out the hole, your center mark is now gone, making it >much harder to align the plate on the lathe for further boring. >No question a hole saw is a hundred times faster, when there is no need >for precision size or placement. Jon Use the hole saw in the tail stock. This allows you to do the set up with the center mark, hole saw it out and then finish bore it. Saves a lot of time. Charles [and in a later message from Charles:] It just occured to me reading my own post that the original requestor was a newbie. What might not be obvious to him is that if he does use a hole saw in the tail stock, he should use a low speed and should secure the chuck so that it cannot spin in the tailstock and mess up the morse taper too. There are a number of ways to do this, but with a hole saw the easiest is to use a wrench on the hole saw nut riding against the carriage. With the leverage a hole saw represents it will easily spin if not watched. ------- Re: How to bore these holes? Posted by: "Dave Mucha" dave_muchax~xxyahoo.com Date: Sat Jul 8, 2006 8:43 am (PDT) >use a hole saw in the tail stock, I would thihk that the lathe is not a good place to do the hole saw. but I have not tried it there. Drill presses are often much more efficient than lathes for drilling holes. As for the hole saw, Jon is correct that it is nothing near a precision drill, so expect it to be within about 1/16" of the expected size, usually oversized. A tip for deeper hole hole-sawing, replace the drill bit with a solid, so it does not cut. Also, once you have scored the part, drill a couple holes that will break into the hole saw cut. In this part, drill on the hole part, if you are making washers, drill on the OD part. These holes are chip relief holes. Hole saws have a very small relief for chips, and these holes allow the chips to fall out. WD-40 is a great cutting oil for aluminum. Dave [and in a later message from Dave:] Darn, Frank, I didn't read your post before I wrote mine. Seems I'm not the only person to have figured out how to cut these holes. ------- Re: How to bore these holes? Posted by: "Bob May" bobmayx~xxnethere.com Date: Sun Jul 9, 2006 4:42 pm (PDT) Actually, if the holes merely need to be accurate relative to each other as opposed to being at a particular point on the plate, you can do the job with a hole saw. Just put the two pieces together and do the hole as one pass and the shaft will be square to the plates. They won't be accurately placed relative to other stuff on the plate but you will know that the shaft is accurately square. Bob May http: slash /nav.to slash bobmay http: slash /bobmay dot astronomy.net Replace the obvious words with the proper character. ------- Cleaning up bored hole bottoms? [sherline] Posted by: "Brad Harris" bradellsx~xxgmail.com Date: Tue Jul 11, 2006 8:43 pm (PDT) Hi All, I've been having problems getting any sort of finish on the bottom of bored holes on the lathe (and I guess the mill too, but I haven't done that for ages, so I can't remember). Just nothing but nasty chatter. Is there a technique with the boring bar, or another tool afterwards? Brad ------- Re: Cleaning up bored hole bottoms? Posted by: "Eric" buckeyevsx~xxyahoo.com Date: Tue Jul 11, 2006 9:04 pm (PDT) A good way is to have a boring tool with clearance on the end. Bore the hole about .01 shallow of your goal and once you have your hole sized take the final target depth with the boring tool, similar to facing but feeding the tool in the reverse direction. Otherwise you'll just have to slow the spindle way down and scrape your way there. Eric ------- Re: Cleaning up bored hole bottoms? Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Wed Jul 12, 2006 3:17 am (PDT) Hi Brad, I don't know the application or the material you are using. They are factors in achieving a good chatter free finish on blind hole bottoms. Recently I had that situation. Here is what I did. I was developing a couple of deadeye drill jigs for a friend of mine, a shipmodeler named Keith Harrison, who lives in Canada. Met him on the Internet. He is now on vacation in England and will return on July 28th. He asked me to help him when the drill jigs he made did not do what he wanted. They were based on a design by a gentleman named Harold Hahn. A man of great renown in the ship model world. Normally, when you need a good finish, especially with a boring bar it is difficult because of the nature of the tool. The tendency for "spring" in the bar and having it cut again without any additional feed can be disconcerting and disastrous to your work! So, what I do is to complete the bottom by "scraping" by hand (sort of) without any power to the spindle whether it be in the lathe or the mill. If I really need a flat bottom with a really good finish, I make up a lap and finish the job that way. If the need is to eliminate tool marks. The jigs in question had to have bores of .150" and .115" respectively. By a depth of .070" and .052" to provide a recess for the deadeye blanks to be clamped by a top plate. In a piece of brass that is .250" thick. I bored all the way through and made press fit plugs. The plugs were made in the lathe and faced and then lapped flat and pressed into place, resulting in a nice clean "bottom" with no tool marks. Of course, depending on the application, that might not be possible. But, since I am the "Captain" of this "ship/jig, I am getting away with it. :) That design also renders my jig universal in that I can change the plugs for any thickness deadeye required... Or stepped plugs of different diameters... Hope I helped you. Regards, Jerry G (Glickstein) ------- Re: Cleaning up bored hole bottoms? Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Wed Jul 12, 2006 8:21 am (PDT) Brad: Chatter is caused by a cutting tool that is not rigid or by taking too heavy of a cut. I would suggest solid Carbide boring bars for Sherline sized machines with at least a 2-5 degree front relief as also suggested by Eric. They will give the least amount of problem if properly sized for the job. The lathe speed will also need to be adjusted depending on diameters, length/size of bars used to also prevent chatter and achieve the type of finish desired. Jerry Kieffer ------- Re: Cleaning up bored hole bottoms? Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Wed Jul 12, 2006 8:46 am (PDT) Jerry G: On your flat bottom holes in brass I think you are making life more difficult than need be. I just happen to be boring some holes yesterday that were .102" in diameter and .090" deep in brass. At the highest lathe speed using a Micro-100 BB-100200 solid carbide boring bar the flat bottoms came out almost like a mirror. But of course the real plus side was it didn`t shatter when I looked into it. Jerry Kieffer ------- Re: Cleaning up bored hole bottoms? Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Wed Jul 12, 2006 9:25 am (PDT) Hi Jerry K: No, my life is just fine, thank you..... :) My goal there was to provide a means of replacing the plugs when desired. I have plenty of solid carbide boring bars of all sizes, and use them when I just need a flat bottomed hole milled or bored from the solid. Jerry G (Glickstein) P.S. I was also giving an option to Brad in case he didn't think of alternative construction. ------- Re: Cleaning up bored hole bottoms? Posted by: "Marcus" implmexx~xxaxionet.com Date: Wed Jul 12, 2006 9:44 am (PDT) Hi Brad: There are a couple of ways to make a flat bottomed hole...the method you choose depends on a couple of factors. If you're turning in the lathe, the most critical factor is the depth to diameter ratio...this determines how big and stubby a bar you can get into the hole and still face off to center. Recognizing that you need to traverse the tool tip from the outer edge of the hole to the center, your bar MUST be a tiny bit less than half the hole diameter so the back of the bar doesn't crash into the wall of the hole when you get to the center with the tip. As soon as you have a hole that's more than 5 hole diameters deep, you've got a long skinny bar sticking out, making the tool tip prone to chatter and scream. As Jerry K suggests, carbide bars will help because they're more rigid than HSS or insert bars, but now you have the problem of how to make or get hold of one. On that note, ANYTHING you can do to reduce the stickout of the bar to a bare minimum will help you, as will anything you can do to remove sloppiness from the carriage and cross slide of the machine. Chucking your work as close to the front spindle bearing as possible, and turning the hole first (so the uncut stock on the outside of the workpiece will help support the surface you're turning) helps too. Turning down the speed and increasing the feedrate are other common chatter-reducing strategies. Once your hole gets around ten diameters deep, facing off the bottom of the hole becomes impractical, so the solution is to use a flat-bottomed cutting tool that's guided by the walls of the hole and does NOT traverse across the face you're machining. A counterbore is an example of such a tool...it is used in exactly the same way as a drill is used...simply poke it into the hole to the correct depth and call it done. There are two difficulties that spring immmediately to mind: First, you need to have or make a tool of the correct diameter and end geometry...center cutting end mills can be used if they happen to be the right size...but they must be set up and used with great care because they've got cutting edges on their sides as well as their ends. They can grab in the hole and wreck something really easily, or at best case, they can open up the diameter of the hole more than you wanted, by shaving out the sides of the hole as they're being fed into the hole. Also, end mills are not truly flat on the ends, they're ground to be a tiny bit concave, so the bottom of your hole won't be truly flat. Last, they take a full width cut, so the depth control is poorer, and the finish at the bottom of the hole won't be too nice, but for lots of things this is unimportant. A custom ground tool can, of course be made, but only if you've got the gear and the knowledge to do it. An excellent work-around to all these problems is Jerry G's suggestion to drop a flat faced cylindrical plug into the hole to form the bottom. Cheers Marcus ------- Re: Cleaning up bored hole bottoms? Posted by: "Charles Fox" cafox513x~xxgte.net Date: Wed Jul 12, 2006 9:53 am (PDT) Jerry K wrote: > the real plus side was it didn`t shatter when I looked into it. Better Magnaflux it, just to be sure you didn't miss some potentially destructive new cracks... ------- Re: Cleaning up bored hole bottoms? [sherline] Posted by: "Marcus" implmexx~xxaxionet.com implmex Date: Sat Jul 15, 2006 7:35 pm (PDT) "Tracy Atkinson" wrote: > Can't you make a flat, well-finished bottom in a blind hole with a > straight D-bit or a twist drill ground flat on the end? Hi Tracy: You cannot get the same quality of finish nor the same accuracy as you can with a facing operation. This is because you're taking a full width chip, so it tends to tear and chatter. You've also got a severe constraint on the geometry of a center cutting tool...no positive rake, and invariably a center zone that has almost no gullet depth to permit chip clearance if you have a multi fluted tool. So the middle of the cutter drags and scrapes even while the outside is cutting reasonably well. This requires comparatively heavy cutting pressure on the tool which exacerbates the accuracy problem. Typically, you have to expect that you'll struggle to hold tolerance of 0.002" without a fair bit of effort, especially in steel. If you need to polish or otherwise finish that surface, you'll immediately see what I mean about the roughness of the finish from this kind of operation as compared to a fine faced finish. The problem worsens as the diameter of the hole increases, largely because you need to reduce the surface speed to stay within the proper range at the periphery of the tool, so you're going way too slow toward the center to get decent cutting performance. So, as I pointed out in my previous post, your decision as to what you can get away with will be governed by the depth of the hole compared to its diameter. Deep holes are MUCH more difficult to get smooth and accurate by facing...the problem worsens as the ratio worsens but the relationship is not linear. So a hole 2 diameters deep is not twice as hard as a hole one diameter deep...it may only be a little bit harder, but a hole 3 diameters deep may be 10 times harder or even impossible with a facing operation if the hole is small in diameter. If you poke in a formcutter (the two examples you mentioned fall into that category) you'll get the same crappy finish and poor depth control regardless of the depth to diameter ratio. Cheers Marcus ------- Re: Cleaning up bored hole bottoms? Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Sat Jul 15, 2006 9:15 pm (PDT) Tracy: Listen to the voice of experience! Obviously, Marcus, (as I have) has "been there and tried to do that"! My suggestion (providing you can have a separate press fit plug, is the way to go). It allows open access to the very surface you are trying to control. If you need even a finer finish, don't "face"" the plug. Grind and lap it! The depth control is a breeze. Just make the plug to the height you require and press it in. Jerry G (Glickstein) ------- boring tool [sherline] Posted by: "ferrigan1" rferriganx~xxcarolina.rr.com Date: Thu Jul 20, 2006 5:53 am (PDT) I purchased a boring tool from Sherline, and can pretty much figure it out with exceptions. I cannot find an index mark on the head for adjusting the diameter of the bore. Should there be one? Also, the 4-40 screw dial is loosly fitted to the screw, in fact one can push the dial head away from the head of the screw, so it turns freely. Should I be using the hex wrench supplied, to turn the screw dial, moving the head, and not touch the dial at all? It is not clear if I should leave the cap screw, while boring, loose enough to move the bottom slide with the screw dial. Usually, the directions that come with the accessory are well written, but I guess I need lots of help on this one. I pre-drilled a 1"x1" piece of brass, using a 1/4" drill. The hole is off center by about .040" in both the x and y directions. My bore ultimately needs to be .500". Can I correct this mistake easily? Thanks, dick ferrigan ------- Re: boring tool Posted by: "Eric" buckeyevsx~xxyahoo.com Date: Thu Jul 20, 2006 9:21 am (PDT) I have one of the same gripes about the boring head. For setting you just need to pick a point and use that as the indexing mark. I use the edge of the dovetail. The dial should be secure on the cap screw though. I would remove it and put a bit of epoxy on there to glue it on. When in use the slide should be locked/tightened down. You can adjust the center line of the hole without problem. Just make your adjustments before you reach the desired diameter. Eric ------- Re: boring tool Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Thu Jul 20, 2006 1:45 pm (PDT) Hi Dick: In my opinion, the Sherline Boring Head leaves a lot to be desired. (I know I will elicit a response from Jerry K! :) So much so that I gave my Sherline Boring Head to a gentleman on this list. And, I built my own... Go to the Photos Section and look in my album entitled "Jerry G's Junk". You will see a picture of The Sherline and the Glickstein, side by side. To answer your question. Yes, you can correct the location using any boring head. Just move the X and Y to the right intersection, and bore it in. Regards, Jerry G (Glickstein) ------- Re: boring tool Posted by: "Smitty" TORYRANGERx~xxwi.rr.com Date: Thu Jul 20, 2006 2:00 pm (PDT) I've read the differing opinions on the Sherline boring head. As a machinist I find that it is as accurate as you should need for hobby machining. I think that Jerry G's opinion of it is based on the fact that as a tool maker he had and used better tooling in the tool room than I did in a production shop. Jerry K gave some good ideas on how to improve the repeatability of the boring head. I found consistancy is the key with the Sherline or any boring head. Other than that, I found that a small amount of pressure holding the moveable half of the head so that the screw stays in contact with the "stop pin", and always coming up to the mark in the same direction will allow you to get consistant adjustments. Smitty ------- Re: boring tool Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Thu Jul 20, 2006 2:36 pm (PDT) Dick: A Sherline Boring head may or may not come from the factory with a Dial index mark. I have seen them both ways. You can contact Sherline or scribe a line/Punch mark in a location of your choice. The Adjustment of this tool is different that a standard Boring head. You first loosen the slide locking screw and then adjust the dial to the desired setting with your fingers since it will be loose. Next with one finger apply pressure to the dial side (Not the Dial Face) to force the slide against the banking pin inside the head and tighten the locking screw before removing your finger. This procedure will allow you to make accurate adjustments in both directions without any backlash calculations as with a standard Boring head design. The 4-40 threaded dial as it comes from the factory can be a pain depending on how loose it is. There are a couple of ways to fix this problem. A fast simple method is to remove the lower slide and put a punch mark over the top of the thread until you have some resistance. However this will not last over the long haul. On mine I drilled and tapped a 2-56 hole from the bottom of the slide so that it intersected the 4-40 dial thread. From that point I installed a 1/16" plastic ball and a set screw to hold a set tension on the dial thread. I have found this modification to be well worth the effort even though it may seem like a pain on a new tool. All Boring heads will bore holes centered to the center of the spindle by the nature of their operation. You can center the spindle by whatever means before boring as one option. OR you can take a light undersize cut and adjust in any direction. By taking several undersize cuts you can adjust the position of your hole until it is located where you wish before taking the final cut to size. It is of course always best to drill an undersized hole before boring if at all possible. The hole need not be centered but must be within the finished bore size. Jerry Kieffer ------- Re: boring tool Posted by: "Mark Iennaco" miennacox~xxyahoo.com Date: Thu Jul 20, 2006 11:23 pm (PDT) Adding in my $.02. The tip of the #4-40 adjusment screw on mine was a little rough. Just enough to cause a couple of .001 high spots over a turn. I used a couple of #4 nuts to let me chuck it in the lathe and used a "Swiss File" to put a slight curve on the end of the screw. It has worked much better since then. I don't know how common a problem this is, so YMMV. Mark Iennaco ------- Re: boring tool Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Fri Jul 21, 2006 2:51 am (PDT) Hi Mark: This is a reflection of parts made in mass production... But, while that is entirely normal, and easily corrected, my main disappoint- ment in the Sherline Boring Head design is the fact that it does not "drive" in both directions... I know of no other boring head that doesn't. Jerry G (Glickstein) ------- Re: boring tool Posted by: "Marcus" implmexx~xxaxionet.com Date: Fri Jul 21, 2006 8:12 am (PDT) Except for mine, which "drives" in neither direction. I set it with gauge blocks or feeler gauges. Far more accurate, far quicker and more reliable to set, and dirt simple to make as an afternoon project. Cheer Marcus ------- Sherline's Boring Head [sherline group] Posted by: "Andrew" trumpy81x~xxoptusnet.com.au Date: Sun Jul 23, 2006 9:25 am (PDT) GDay All, I recently had cause to use the sherline boring head and I was not entirely happy with its operation. First problem: It seems to me that the adjustment dial needs some rework as mine decided to part company in the middle of the boring operation! Any suggestions about this problem would be appreciated. I'm not apt at ducking from ballistic missile's ;) Second problem: After I finished boring I noticed that whilst I had a very nicely finished hole, it was tapered from top to bottom. I realise that the boring bar I used was a little long, 40mm and it has a 3/8" shank and is quite stout, but I didn't expect to get too much flex from it, or the machine for that matter. I can only assume that I overlooked something, somewhere. Any hints. tips or advice on using this tool effectively and safely would be greatly appreciated. ------- Re: Sherline's Boring Head Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Sun Jul 23, 2006 11:56 am (PDT) Hi Andrew, I will leave the "how to" with the Sherline Boring Head to Jerry K, who digs it! As far as your taper. That is indigenous to all boring bars...Aggravated by longer ones. The only work around is to "creep" up to your finished size, and take many "spring cuts". Or ream to size, or depending on the material, hone it, or "ballize" it. Jerry G (Glickstein) ------- Re: Sherline's Boring Head Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Sun Jul 23, 2006 12:20 pm (PDT) Andrew: Actually Jerry G will be very envious of your Boring head's performance. I doubt that his Boring head is capable of boring a "Very nicely finished tapered hole". Actually if you have a tapered hole most likely your boring head slide moved because the locking screw was loose or something was loose on your setup. (Work piece,Mounting Arbor, Mill Column etc.) If your dial head came off of the threaded dial rod that is something you need to discuss with Sherline. If the threaded dial rod unscrewed, the head was not setup and adjusted properly with the threaded rod seated against the banking pin with light tension. I outlined my personal setup procedure for this boring head in recent post #29970 that should eliminate these problems. Jerry Kieffer [NOTE TO FILE: Jerry's setup instructions are here in his posting dated Jul 20, 2006 a few messages above.] ------- Re: Sherline's Boring Head Posted by: "Jerry G" chieftoolmakerx~xxearthlink.net Date: Sun Jul 23, 2006 12:35 pm (PDT) Mr Kieffer, I do not use my boring head to make a "Very nicely finished tapered hole". If I need a tapered hole , I use a *HDTPR... Regards, Jerry G (Glickstein) P.S. Andrew, Get thee hence to post #29970, and be cured of all your Boring Head problems....P.P.S. * = Helical Diemaker's Taper Pin Reamer ------- Help with boring using an end mill [taigtools] Posted by: "Jim" samadams4qx~xxyahoo.com Date: Tue Aug 1, 2006 12:00 am (PDT) I need some advice here. I'm trying to bore a hole in a block of aluminum for a press fit bearing to fit into the end of it. I don't have a boring head (yet - More shopping at LMS soon!) and thought I might be able to accomplish this using my CNC taig. The bearing is 22mm dia. and about .275 inches thick. I will use a roughing end mill to get the hole "close" and then switch to a four flute 1/4" hss mill to finish it up. My questions are: What is the best direction for the finishing pass? A Climbing cut (table moving in a clockwise direction) or CCW? And, is it better to start with the mill up at the final diameter and work down on each pass, or start at depth and work outwards with each pass? There is already a 1/4 inch hole through the block so swarf buildup shouldn't be to much of a problem. BTW, CNC on this mill is amazing and I know I've only scratched the surface at what it can do. Thanks, Jim ------- Re: Help with boring using an end mill Posted by: "Richard" phrhx~xxworldnet.att.net Date: Tue Aug 1, 2006 4:15 am (PDT) Use a tap properly positioned. Richard [LATER MSG] Don asks: Did you mean Reamer???? :>) [LATER MSG] Richard replies: No not a reamer! I often use a small tap as a boring bar. Just position it so that one of the cutting edges is centered to match the lathe centers and use it like a boring tool. The tap teeth on one row work like a boring tool with lots of cutting teeth. Mount one in your tool holder and take a look and it should be obvious. Great for very small holes. ------- Re: Help with boring using an end mill Posted by: "campgems" Donx~xxCampbell-Gemstones.com Date: Tue Aug 1, 2006 9:04 am (PDT) Jim, if the work is small enough, try using the mill like a lathe. There has been some talk about doing that on this list a while back. Chuck up the work on the spindle, mount a lathe bit on the bed and start cutting. Use the Y to set up the tool on the center line, and use the X as the cross feed, Z becomes travel. You are limited in size by what the chuck will handle and clearance to the column. Of course, this all assumes you have a Taig lathe for the chuck and tool post, etc. Don ------- Re: Help with boring using an end mill Posted by: "Jim" samadams4qx~xxyahoo.com Date: Tue Aug 1, 2006 10:26 pm (PDT) Thanks for the reply, Don. The block is too big to chuck or turn in any lathe I could fit in my shop. I received an e-mail from another member who suggested that a 1/2" two flute end mill was a better choice for the finish cut than the 1/4" one I mentioned. Also that I should start at full depth and use a climbing cut for the finish (last .005). I used a simple 1 line g02 code with the correct radius accounting for the tool width and it worked perfectly! The bore was as smooth as some I've cut on my lathe and the bearing was a very snug fit. I was afraid that the boring circle created by CNC wouldn't be as smooth as one created with a boring head, but I was way wrong. Every day I learn more! Jim ------- Drilling 3" deep? [taigtools] [BORING turns out to be the main subject] Posted by: "derekgammage" derekgammagex~xxyahoo.com Date: Mon Feb 4, 2008 11:01 pm ((PST)) is it possible with a taig lathe to drill a 1/2 hole throught the center of a round brass rod 1" to 1 1/4 OD up to 3" long. i am considering a taig but i was told that it is not big enough for this job which will be my 1st step. i was also told, by someone else that it is possible but i would have to do it in steps. by steps did he mean positioning the tailstock, then drilling as far as i am able then backing out repositioning the tail stock and repeating? ------- Re: Drilling 3" deep? Posted by: "Tony Jeffree" tonyx~xxjeffree.co.uk Date: Tue Feb 5, 2008 12:04 am ((PST)) Derek - It is certainly possible to do that (and much more) on a Taig lathe, but it needs to be done with care. Drilling in brass can be difficult because brass has a tendency to "grab" - the drill tends to be pulled into the material as it cuts. For this reason, special drills are often used with brass - either ones that have a "slow spiral" - the flutes aren't as tightly twisted as with normal twist drills - or ones that have zero rake on the two cutting edges at the end of the drill. You can modify normal twist drills to have zero rake by stoning a small flat on each cutting edge. What "someone else" meant when they talked about drilling in steps was using progressively larger drills, each time drilling to full depth. While this is certainly a possible technique, it does tend to exacerbate the "grabbing" problem - drilling the first hole will be relatively easy, with grabbing only being an issue when the drill breaks out at the far end of the hole (if you are drilling all the way through), but drilling the subsequent holes there will be a good chance of the drill grabbing. If you are willing to modify some drills for zero rake, then that should work just fine. However, as twist drills tend to cut oversize and can wander off axis on a deep hole, you will probably want to cut the last few thou using a boring bar rather than a drill, or if you want super accuracy, drill then boring bar then reamer. For these reasons, I would be tempted to drill the first hole using a drill large enough to accommodate a small boring bar and then finish to size with the boring bar rather than using step drilling. The boring part be - er - boring, but you won't have any problems with the drills grabbing. Regards, Tony ------- Re: Drilling 3" deep? Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Tue Feb 5, 2008 12:14 am ((PST)) The one thing to keep in mind if you feel you need to bore the last few thousandths is that a boring bar small enough to fit in a 1/2" hole will not be very strong if it is long enough to bore 3" deep. You'd be better off boring only the first 0.5" or so to get a reamer going straight and then reaming the rest of the hole. A few days ago I was boring a piece of 1.5" ID (2.5" OD) aluminum tubing out to 1.540 for 3.5" deep on my 12x36" Atlas, a significantly larger lathe than a Taig. I was using my largest boring bar, a 3/4" shank beast that fits comfortably in a 1.25" diameter hole, and I was still getting deflection 3.5" in. You might be able to do it with carbide shank boring bars, but not in a Taig. ------- Re: Drilling 3" deep? Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Tue Feb 5, 2008 9:05 am ((PST)) Hi Derek: Step drilling is the way to go, and then boring for a finish. If you look at the business end of a twist drill, there is a "dead" spot where the point meets the gully of the flutes. This is called the "web". So, commence by center drilling the rod after facing it off for a smooth working surface. Then, select a small drill that will be about 5/32" or so. Drill through. You can also at this point reverse the work to drill from the other side. Any mismatch will be removed and corrected when you finish bore the hole. Select the next drill by seeing that it will cut with its outer lips only and not involve the web of that drill. That is the basic procedure for Step Drilling. More later.... Jerry G (Glickstein) ------- Re: Drilling 3" deep? Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Tue Feb 5, 2008 10:20 am ((PST)) > is it possible with a taig lathe to drill a 1/2 hole throught the > center of a round brass rod 1" to 1 1/4 OD up to 3" long. i am > considering a taig but i was told that it is not big enough for this > job which will be my 1st step. Whoever told you this is correct. While just about anything is possible, it is not something an experienced person would ever do the second time on a Taig sized Lathe. I could send you a picture of myself to show you what someone Dumb enought to do something like this the first time looked like. The first thing you will find is that securely and accurately holding a 3" long piece of stock with jaws that are under .750" long on one end is just not practical. If you must do this you will need a steady rest for support. Next you will find that normal 1/2" drills are to long with the bed space provided. Depending on your Tailstock Chuck stub drills may not even work. Then you have the problem of only about 1" of Tailstock Ram travel. This means you will constantly be relocating your tailstock. Unless you are very careful and have all day your hole will end up looking like a birds nest. Small lathes ARE MADE TO MACHINE SMALL PARTS. They can be highly efficient when used as designed to be used. For this type work I would suggest a Lathe with a Chuck large enough to properly grip your stock in the middle of its length. If all of your other parts are small parts you may want to farm this job out if you are short the proper equipment. Jerry Kieffer ------- NOTE TO FILE: The following conversation is primarily about boring techniques and hence was put into this file. ------- Locating scribe marks [sherline] Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sat Apr 26, 2008 5:17 pm ((PDT)) I am having a bit of trouble getting enough accuracy in a part I am machining. The part is a 2 inch long 1.375 inch cylinder. A large cavity is milled in the center of the length of the cylinder, making it somewhat horseshoe shaped, that was the easy part. I need to machine two holes in opposite ends of the cylinder. The holes are not on the centerline of the cylinder and they need to be concentric since they will support shafts that have to run through bearing on opposite ends of a gear case. So the question is how to accurately machine the holes. On my first attempt I scribed the centers of the holes on each end using a height gauge and surface table. I feel confident that I accurately scribed the markings. However I am not so confident that I accurately positioned the spindle over the scribe marks. I used a #1 morse center in the spindle to line up visually over the scribe marks, but at the end of the day it looks like my holes were aligned, but about 15-20 thousands off center making fitting the shaft very difficult. So, in the case where you have no convenient edges to locate (like on the end of a cylinder) what is the best way to line up the spindle? Craig http://enderw88.wordpress.com ------- Re: Locating scribe marks Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Sat Apr 26, 2008 5:24 pm ((PDT)) If I'm visualizing the problem properly, you drill it undersize, then line bore the hole. ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sat Apr 26, 2008 6:02 pm ((PDT)) How do you line bore? ------- Re: Locating scribe marks Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Sat Apr 26, 2008 6:43 pm ((PDT)) Craig: If you are sure that you got the scribed marks right, you can lightly prick punch them under magnification. Then take something like a 1/8" piece of drill rod long enough to reach from the tailstock chuck to the part when mounted in the 4-jaw chuck. Grind and hone one end of the rod to a sharp point and hold the other end in the drill chuck. Bring it to the work just until it touches, guiding the point into the punch mark. You can use a test indicator against this rod to get the punch mark on the spindle centerline. You will have to get pretty "eyeball" close before using the indicator, since a 1/8" rod doesn't give much surface to bear on. If your indicator has a flat "shoe" point you can start a bit earlier. The neat thing here is that the pointer doesn't even need to be accurate - just sharp - since you are measuring, and minimizing, its movement rather than its center. The reason I suggest 1/8" rod is that it should be flexible enough over the length of a Sherline bed to follow the punch mark. A larger diameter rod could be used if it has been center drilled at the tailstock end. In that case you can use a tailstock center. Following suggestions from here and other web sites, I made one for myself from 1/4" rod, brass tubing, and a spring. That way I can use spring pressure to keep it between the part and the tailstock center. If it is solid, you need to get your mark pretty close so that the rod doesn't drop out while measuring. Remember in every case that you don't want the measuring rod to rotate at all, just the part you are lining up. Alan ------- Re: Locating scribe marks Posted by: "enderw88x~xxgmail.com" Date: Sat Apr 26, 2008 7:17 pm ((PDT)) How would this work on a mill? ------- Re: Locating scribe marks Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Sat Apr 26, 2008 7:51 pm ((PDT)) Craig, I'm not sure there is a corresponding way to do this on the mill. The whole concept depends on the work revolving around the punch mark. It may be that someone like Jerry or Marcus has either another technique or a modification of this one. Alan ------- Re: Locating scribe marks Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Sat Apr 26, 2008 9:16 pm ((PDT)) Hi Craig: There are a couple of ways to do this kind of work accurately. NONE of them involves scribing and picking up to a layout line. If the bore is not too deep. it can be machined all from one end...this is the most accurate for alignment but you are limited in the depth you can reach. If your bore is too small to allow a rigid tool (like a boring bar) to make it all the way through, then you have to work from both ends, and this is where a bit of ingenuity will help you. One very effective way is to start with an oversize block, long enough that you can turn the whole length of the part in one chucking, and big enough in diameter that you can cut the eccentric body later. Turn it smooth, bore the first hole before you take it off the lathe, then cut it off to length. Set up the second side in the 4 jaw chuck and dial it in accurately with a good DTI on the smooth outer diameter that you turned in the first step, then turn your second bore to size. This will make both bores co-axial to within the limits that you dialed in to. Now you can set up the part offset in the 4 jaw and machine the eccentric part, then all the other features. If the offset is so large that you'd need a massive chunk of stock, or if you're working from a casting or a billet that's too small to do it this way, you need to create a flat reference face from which to work, before you poke in the holes. There are two ways to do this...you can machine a reference plane along the length of the cylinder as a first step, or you can clamp a reference plane onto the cylinder. A very convenient way to do the latter method, is to simply clamp the cylinder laying down sideways in the milling vise, then tip the vise up on its side, or tilt the milling head over sideways, to gain access to each end. Then indicate the end in with your DTI, offset over the amount you need using the graduations on the appropriate handwheel, and poke in your hole. You need to indicate the base of the vise parallel to either the X or Y axis of the mill, BEFORE you clock in the center of the part and perform the handwheel offset motion. This will ensure the holes are coaxial. As before your stock needs to be smooth and reasonably parallel. So long as you don't unclamp the part from the vise until all operations are done on both ends, you'll be as accurate as the vise is square and parallel. This method is not as accurate as the first method, and if you examine the methods closely you'll immediately see why. The first method assumes the part is clocked in with no runout, and the coaxiality depends on only one measurement...the accuracy of your dialling in of the second side. The second method has a lot more measuring in it, and a lot more asssuming is done (the handwheel graduations are accurate, the vise is square and parallel, the machine motions are flat and orthogonal, the head is not tilted, etc etc ). Using method #1 you can expect to get the bores coaxial within 0.0001" with a good clock and a modicum of care. Using method #2 you can expect to get coaxiality within 0.001" to 0.002" with the same level of care. Scribing and aligning by eye, even with magnification will likely get you within 0.005" with a very meticulous setup and within .010" with normal care. Notice that the accuracy is much more dependent on the method, than on the time or care taken, and the scribing method is intrinsically roughly 100 times as uncertain as method #1. You'll be out a couple of thou just from the width of the scribe line assuming you can scribe exactly where you thought you were scribing, and assuming your scriber blade is still in perfect condition...I have to re-dress mine about once a year on a diamond wheel to keep it in good shape. My Mitutoyo height gauge is an expensive model, but it's only within a thou or so if I calibrate it against my gauge blocks. A 150 dollar Fowler will be out a fair bit more. If you have a burr on a reference surface from which you're scribing, you can easily add another 0.005". Using a 10X magnifier, I can pick up a scribed cross within 0.005" routinely on each axis using the milling machine to move the job around under the center drill. If I center punch, and pick up the punch marks, I will routinely miss by another 0.010" or so on each axis. You can see where this is going...you don't have a prayer of hitting your target consistently using the layout method, and for a small diameter shaft with 0.001" running clearance (which is a lot!!), you'll never make a good job of it except by accident, no matter how careful you are. Cheers Marcus ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sun Apr 27, 2008 7:09 am ((PDT)) Marcus: Thank you for describing how accurate locating a scribe can be. As it is it looks like my first part was about as good as locating to scribes can be, and it wasn't good enough. I will investigate the other setups you mentioned. ------- Re: Locating scribe marks Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Sat Apr 26, 2008 11:02 pm ((PDT)) I do it on the lathe, but I suppose you could figure out a way to do it with a vertical mill. It'd be easy on a horizontal mill, if you had access to one. Basically, I'd center drill both ends of a steel bar, and mount a piece of drill rod sticking out of the side of it. Sharpen that piece of drill rod to get a cutting edge, the distance from the center that you want to bore out. Mount this tool between centers, and drive it with a dog. If you need to, you can swap it end for end without losing concentricity. Clamp the work piece to the carriage and feed it along the boring tool. ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Sun Apr 27, 2008 4:16 am ((PDT)) Pierre, Yes, Line boring is the way to go..... But perhaps Craig does not know what, or how to line bore. Jerry G (Glickstein) ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Sun Apr 27, 2008 4:16 am ((PDT)) Craig, "Line boring" to me is done in the mill. (or a jig bore.) Usually done on parts that need bores lined up that have some length to them, but not necessarily. You set up a workplate. Bore a hole in the center. Press in a close fitting plug. Lock the X and Y axes. The idea is to place your work's previously bored hole on a close fitting plug that is pressed into the workplate. If you have aligned the spindle well, and the Z travel is true, the second bore will be in "line" with the opposing bore. Requires inversion of the part for the second bore. Hope I explained it correctly enough for you to get it. Regards, Jerry G (Glickstein) P.S. There are other types of line boring also. ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sun Apr 27, 2008 7:10 am ((PDT)) [Jerry:] I get it, that might be an option. Thanks Craig http://enderw88.wordpress.com ------- Re: Locating scribe marks Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Sun Apr 27, 2008 8:08 am ((PDT)) Craig: What is the diameter of the hole you are drilling? And is it offset into the center of the solid left or does it pass through the cutout section? Alan ------- Re: Locating scribe marks Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Sun Apr 27, 2008 9:34 am ((PDT)) While not disputing any of the other advice given on dealing with your particular issue; if you do ever need to accurately locate a hole by scribed lines alone, here's how to do it: 1. Use layout fluid to maximize visibility, but scribe the lines deep enough that you can feel them with the point of a needle-sharp scriber. 2. Use that sharp scriber to trace the lines to their point of intersection. Then press down hard, wiggle and rotate the scriber to make a tiny dent at that point. 3. Put on your Opti-Visor. With a center punch, ground and sharpened to around 60 degrees, pick up the dent and tap the punch with a hammer to enlarge it slightly. 4. Examine this punch mark to ensure that it's exactly at the intersection. If not, it can be moved by tapping it over with the punch held at an angle. Be sure that the last tap is vertical, symmetrical, and deep enough to obliterate previous attempts. 5. Further enlarge the dent with a standard 82 degree center punch. 6. Start the hole with a drill no larger than the diameter of the punched depression. You want the drill to be able to flex slightly to follow the center. But, you don't want it to start going off perpendicular. Use only minimal pressure, and go only deep enough to provide a good start for the next drill - a few diameters. NB, rigid center drills are used ONLY when the location is fixed by the machinery, and you DON'T want the point to wander. NOT to pick up a center punch mark. Here you WANT the drill to follow the mark. (This is a point of much confusion and contention, even among experienced machinists. The proof is in the results; try it and see.) 7. Enlarge the hole with successively larger drills to reach the final size. After the second drill, the work may be clamped in position. Use a dead center, or a dowel pin the same size as the last drill, in the chuck, inserted in the hole to hold the work in position while clamping. It is not necessary, nor necessarily a good idea, to drill to full depth with each successive drill. Each hole needs only to be large and deep enough to ensure that the next drill starts and stays on center. A good rule of thumb is 5 drill diameters or less. The size of each drill should be such that the diameter of the previous hole falls between the chisel point and the margins of the next drill. If the final depth of the hole is less than 5 times the diameter, there's little point in drilling intermediate sizes. That's a lot of words, and may seem a bit complicated. But with a little practice you can locate and drill holes, straight and true, to positional accuracy of +/- .001" with this technique in only a few minutes. It's often much faster and easier than locating a work piece in the mill and dialing in the location; especially if you only need a few holes. It's a good skill to develop. regards, DC ------- Re: Locating scribe marks Posted by: "Ian Newman" ian_newx~xxyahoo.com Date: Sun Apr 27, 2008 11:28 am ((PDT)) Hi, I've read this thread with interest but there are a couple of points that spring to my mind that no-one seems to have mentioned: First: To accurately pick up lines marked on opposite sides of a piece of work, you must have established a couple of good reference surfaces to mark and measure from. Rather than locate on the scribed lines, use your reference surfaces to set up toolmakers buttons to locate the holes, then centre the tool on them. Second: No matter how accurately you pick up the intended centres, you will never get a true hole cut to the correct size using a drill - especially if you pilot the hole first, then use progressively larger drills (normal twist drills are very flexible things and you will get lobing resulting in an oversized hole. The same flexibility will also result in a hole that follows a slightly curved path). If you need an accurately sized hole it needs to be reamed, if you need an accurately aligned hole it needs to be bored. Ian ------- Re: Locating scribe marks Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Sun Apr 27, 2008 4:32 pm ((PDT)) Hi Ian: Excellent points!! Thanks for bringing them up. Cheers Marcus ------- Re: Locating scribe marks Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Sun Apr 27, 2008 4:07 pm ((PDT)) Hi Dave: This is the first time I'll have to respectfully disagree with you on a point of technique. Getting a hole located within 0.001" CONSISTENTLY is quite a challenge on a milling machine, even with accurate edge finding protocols and a commercial sized machine in good condition. So many things conspire to throw you off: the table rocking, the head not square, the quill shifting when it's clamped, the vise not square, the workpiece not aligned, the gib clearance allowing the table to shift and on and on. Picking up to a scribed cross is even worse, particularly when you allow the drill to be picked up on a center punch mark. Twist drills, even short, stiff ones like spotting drills and center drills won't retain their position terribly well until the drill is deep enough into the workpiece that the parallel part has penetrated into the workpiece. So, for the entire time you're drilling with only the conical point, you're wandering around the desired location as the forces on the cutting edges change, especially the chisel point that cuts only with a scraping motion. Since no drill has perfect geometry, all holes will drift to some extent until the sides of the drill can start to do some guiding, and even then, the mismatch of hole to drill diameter allows the drill to flop around a bit. As you point out, a way to get around this to some extent, is to punch deep enough and use a small enough drill to envelop the whole drill point in the punch mark, so it needs to cut only a very short distance before it is guided by the drill sides. This pilot hole can help to guide successively larger drills as you recommend, but each drill will need to start on the sharp corner of the existing hole, and will establish its location depending on which spot on the hole gets first contact and either sucks the drill toward it or pushes the drill away from it, which in turn depends on such things as rake and clearance, the sharpness of the drill and the evenness of the drill grind. A further problem, is that a large punch mark is harder to assess for location visually than a small one, so by the time you've given the part a good bashing to make a wide dimple, you've invariably lost the precision of the first prick punch mark. The third part of the problem comes when, as you correctly point out, you let the part float so the drill will auto-locate over the hole. The drill will only be in approximate location when you start, so it will approach the punch mark off location, and the drill will flex sideways as it tries to pull the workpiece under the axis of the drill. If the drill is small and the workpiece big, it will never pull the workpiece into the proper spot. Also, the drill will start to carve away on one side of the punch mark, so even when you've punched accurately, you lose much of your accuracy effort as the drill starts to do its thing. A way to mitigate this problem is to use a radial drill and don't clamp the column or the saddle, so the spindle can float instead of the workpiece floating. If the radial drill is smaller, well made and in good condition, it's not a bad way to get the holes pretty good (+/- 0.010" or so) relative to where they're supposed to be. Next, clamping the part using a dowel to locate the pilot hole (I assume in the drill chuck) is problematic in two ways: First, the drill chuck is no where near concentric...in fact, many collets aren't that great either. Second, the drilled pilot hole is neither accurate nor round, so an approximate best fit is all you can hope to achieve. Third, only a very good quality drill press has the table reasonably square to the spindle with a lapped quill in a lapped housing, so a good location with a short dowel and the quill extended, doesn't translate to a good location with the quill retracted and a drill in the chuck. Fourth, the clamping process always pulls the part out of location a bit. So, having gone through all that, I will agree with you that your technique is the proper way to squeeze best possible positional accuracy out of a hole that can only be located to scribed lines. My disagreement is only that you can realistically expect to be consistently within 0.001" of your desired location with ANY technique involving a scribed location reference and visual positioning. Cheers Marcus ------- Re: Locating scribe marks Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Mon Apr 28, 2008 6:36 am ((PDT)) Hi Marcus: No real argument here, and thanks for an excellent explanation of everything that can go wrong with drilling a hole. I don't advocate the technique as a production method, but, when I do need to drill to scribed lines, or it's just the fastest, easiest way to get the job done, I can nail it pretty damn close most every time. I do encourage the newer hands to try it, they might be surprised at how close they can come. And it is a useful skill. DC ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Sun Apr 27, 2008 5:13 pm ((PDT)) Hi guys: A drill is not a finishing tool. A reamer might be, if you can get it to hold the size, but too often, the material "welds" to the cutting edges, resulting in an oversized hole (what I call a "bloop fit"). But it too will follow the previous hole by "leaning" on the material. The answer is single point boring. This can and will create an accurate bore, capable of correction of any out of position condition if need be. Drawback? Taper and "bellmouth", but those conditions can be circumvented and/or corrected. My 50th of a $. Jerry G (Glickstein) ------- Re: Locating scribe marks Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Sun Apr 27, 2008 6:04 pm ((PDT)) Hi Jerry: Agreed. Now; how would YOU go about locating and boring two coaxial bores, one on each end of a cylinder, not concentric to the centerline of the cylinder, and needing to be accurate enough to run a shaft through the two bores with 0.001" clearance. Craig's original specs are paraphrased here: > I am having a bit of trouble getting enough accuracy in a part I am machining. The part is a 2 inch long 1.375 inch cylinder. A large cavity is milled in the center of the length of the cylinder, making it somewhat horseshoe shaped < For the purposes of this discussion, you don't get to do it all from one end...you have to set up each end in turn, but neither bore needs to be very deep; say depth of one hole diameter to get through the wall thickness on each end of this hollow cylinder. It's a great problem to illustrate the limitations of the various methods available to home shop machinists. So you don't get to use a jig borer, or a wire EDM either...only your trusty mill or lathe (or both). Give us the full meal deal...every step in loving detail down to the last gauge block setup. Let us know also, what you expect the inspection department to find when you're finished. I've given two methods...Ian Newman has given a very good third method using toolmaker's buttons. You've given us some hints about a fourth method. Now it's your turn for a full Monty!!! :<) Cheers Marcus ------- Re: Locating scribe marks Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Sun Apr 27, 2008 8:33 pm ((PDT)) Marcus: It's not clear from Craig's information if he is placing the hole off-center through the open part of the "horseshoe" or through the closed back part. It's also unknown just what sized hole he wants. Hopefully he will furnish this info since it can make a difference in method. Alan ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sun Apr 27, 2008 8:51 pm ((PDT)) Sorry, it took so long, this has been very good general information. In this particular case the part is 2 inches long 1.375 inch diameter, the 1/2" shaft is 0.225 inches off the centerline of the cylinder. They are off center through the open side of the "horseshoe". At this point, since the critical dimension is to actually keep the shafts aligned, and not as close a tolerance on the dimension off axis, I have actually cheated and used my drill press to step drill the shaft hole in the cylinder before reaming it to final size; I will machine the cavity next. The 1/2" reamer I finished with guaranteed concentricity and axial alignment of the hole. However that would not have worked if the holes were blind, and I could see that as a useful exercise. ------- Re: Locating scribe marks Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Mon Apr 28, 2008 12:10 am ((PDT)) > However that would not have worked if the holes were blind Not all blind holes are as blind as others! You might be able to silver solder plugs into the hole. I'm told that this is often done if you want a truly flat-bottomed hole... ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Mon Apr 28, 2008 2:52 am ((PDT)) Hi Marcus: Let's see..... We are looking at a cylinder 1.375" in diameter that is 2.000" long. The problem is to put two holes (diameter unknown) opposite each other to accommodate shafts to go through bearings in a gear case. Correct? I would lay out the first end by using a good V block, height gage, and make scribed intersections at the desired location of the hole. (at 90 degrees.....) Is there a relationship between the 1.375" diameter? Are the holes to be located on the centerline of the 1.375" diameter, or do they fall elsewhere within the area of the circle/diameter? How accurate does the location of the holes have to be? Set up the work on a good set of parallels on the mill table. If there is a relationship, Indicate the 1.375 diameter, move to the first hole location by linear coordinates. Center drill,or spot drill, drill, and then bore the first hole to size.....Now, without moving the work, make sure it is securely clamped, but not distorted by the clamping force. Center drill through the first bore using an extended center or spot drill. Drill, and bore the lower hole to size. The boring head setting can be retracted for the purpose of measuring the second or lower bore. Alternate. Line Boring. Do the first bore as above. Prepare a work plate. Fly cut it for flatness and parallelism. Center or spot drill, drill and bore for a plug which will be pressed into the work plate that is a snug, wringing fit to the first bore. Now, do not move the X or Y axes ( plural?). Register the work on the plug. Clamp securely without distortion. Set up/threaded holes drilled and tapped in the work plate prior to boring in for the centering plug. For the clamps....Center or spot drill, drill, and bore the second bore (on the opposite end of the work piece) to size. You can make a nice fitting plug gage to check the fit, (lathe) and if it is more than 2.000" long, get a good idea of the co axial line up by gently rotating the plug gage......In both bores....I would suggest a thin film of gage oil to prevent galling. Jerry G (Glickstein) In New York, waiting for the comments..... ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Mon Apr 28, 2008 6:26 am ((PDT)) [Jerry:] The shaft is 1/2" OD, and will be pinned into this part so the bore holes should be 1/2" for a light press fit. If I am reading this first method correctly You would do both holes from the same end using the boring head. Unfortunately the overall length is just beyond the capability of the sherline boring head which is the only one I have... ------- Re: Locating scribe marks Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Mon Apr 28, 2008 7:35 am ((PDT)) Craig, Enco's on-line catalog lists a 3/8" shank carbide boring bar that will do 1/2" holes to a depth of 2-3/16. The listed price is $34.31. Hopefully there is a cheaper place to buy one or it will be a sale item somewhere. Alan ------- NOTE TO FILE: During this latest conversation on layout and boring techniques you will soon see that some correspondents try to start a new topic and subject title. Some folks reply to the new title and others reply using the prior title. Can be confusing. If you were to search the group archives by subject title, no matter which title you search, you will get only a part of the overall conversation. In these files, you will likely find a more complete conversation no matter what the title. ------- Between centers boring bar [sherline] Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Sun Apr 27, 2008 4:58 pm ((PDT)) I seem to remember seeing some rough plans for making a boring bar that fit between centers; the piece would be clamped to the cross slide of the lathe and run along the bar. I can't find the information anymore which means it could be one of those hallucinations I am plagued with. Can anyone give me some clues on how to build something like this? That part I can't figure out is how to make it reasonable adjustable so that I can march the diameter out in small increments. Craig http://enderw88.wordpress.com ------- Re: Between centers boring bar Posted by: "Keith Green" ksggx~xxtelus.net Date: Sun Apr 27, 2008 6:03 pm ((PDT)) I've done this on a larger scale on a horizontal boring mill. Same setup on the lathe, really, just smaller. It's a little cumbersome and takes a little preparation and forethought. First you have to determine whether the location of your bore is attainable in the lathe. The height from the top of the cross-slide to the center of the spindle bore is all that you have to work with. You make a boring bar long enough for the whole workpiece to pass by any single point on that bar without said workpiece running into the headstock/chuck or the tailstock which will be holding and supporting the boring bar in it's cut. You mark that single point on the bar that the whole piece is able to pass by and drill a hole there, crosswise, through the bar. That hole should be located off-center so that, when you grind a tool to fit in there, its upper ground surface will be as close to on-center as possible. For a tool bit you can use any cylindrical piece of carbide or HSS. Busted or dull taps work great as the shanks are hardened all the way up. Same for old endmills. Drill bits are OK as long as you stick close to where the flutes begin. Tap a setscrew hole perpendicular to the tool hole through the thick side of the bar so you can hold the bit in. You lay out and rough-drill the holes in your workpiece as close as you dare to the size you require. Clamp the workpiece to the cross-slide of the lathe. Set it up so that the drilled holes are in line with the spindle-bore using one true face of the part for reference. Install your boring bar through the drilled holes and either hold it in the chuck, a collet or drive it with a dog. Tailstock in the other end. Now you have your job bolted to the cross slide with your boring bar set parallel to the centerline of the holes you need to bore. Measure the distance from the tip of your cutter to the back side of the bar. Subtracting half the diameter of the bar will give you the radius of the hole (approx.) that the tool will bore. Turn on the spindle and use the longitudinal feed to feed the workpiece over the rotating tooltip. The cumbersome part comes now, when you have to measure the bore as you have to remove the boring bar from the setup to measure accurately. This is where driving it with a dog will help you as it's easier to take out and put back in accurately. After measuring carefully, put the bar back in and use a dial indicator to adjust the stickout of the tooltip to adjust it for another cut. You can just 'un-snug' the setscrew and tap the tool gently to ease it out a bit. Not too hard or you'll damage the centers and it won't run true anymore. Depending on workpiece geometry, you may have to do this any number of times to get an accurate size through those bores. In the first few cuts you have to determine whether the positioning of the bores is correct and adjust by shimming up or down and adjusting the cross-slide in or out. On long boring bars, chatter becomes a real problem. Slowing down the spindle helps but will often leave a torn finish. Heavy-duty cutting oil applied with a small brush can help with that sometimes. Supporting the boring bar, somehow, closer to the tool tip can help, too. Steady and/or follower rests can help or you can simply apply gentle pressure on one side of the bar with a stick of suitable dimension; just enough to soak up the harmonic. Keith ------- Re: Between centers boring bar Posted by: "David Wood" dave.woodx~xxcomcast.net Date: Sun Apr 27, 2008 6:30 pm ((PDT)) Craig: Rudy K describes and illustrates the making, setting, and use of this kind of boring bar (dog-driven) in /The Shop Wisdom of Rudy Kouhoupt, /Volume 1, pages 14-17. Dave Wood ------- Measuring and boring holes [sherline] Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Mon Apr 28, 2008 11:38 am ((PDT)) This should be a very easy thing to do, but I can't seem to get repeatable results using the Sherline boring head. Here is what I am trying in order to get an accurately sized hole, there must be some technique I am getting wrong: 1. Drill a hole large enough to get the boring head in. 2. Bore the hole slightly large than the drill hole (a few thousands by eye). 3. Using a telescoping gauge, measure the diameter of the hole I just bored. This gives me the starting point with the boring head. 4. Adjust the boring head by some fixed amount using the 4-40 screw with the dial. (Pick any amount, I have tried this procedure with anywhere from 0.003 indicated to 0.02 indicated.) 5. Bore the hole again, go in and out several times to make sure any spring effects have been taken out. 6. Measure the hole again with the telescoping gauge. At step 6 the hole SHOULD be larger than the measurement in step 3 by the amount dialed in on the boring head. But I cannot repeatably get this to work. For example, I have dialed in 0.013 increase and measured a difference of 0.005 in diameter, and worse I have dialed in 0.005 and opened the hole by 0.010. This is frustrating because no amount of sneaking up on my final desired diameter seems to be repeatable. When I use the telescoping gauge I insert the gauge with the hand as parallel to the centerline of the hole as I can get it (usually 30 degrees off since I can't move the tool completely out of the way), release the pins, jiggle the pins so they are hopefully working their way out into the bore, then tighten the pins. To remove the gauge I tilt the handle so the pins don't drag on the bore then measure it with a set of calipers. Any hints on this very basic operation? I have heard rumblings about the Sherline boring head, is there a better one available? I can't tell if the rumblings were skilled people grumbling about a poor tool, or unskilled people blaming the tool for their problems. At this point I am far more likely to blame my incompetence than the tool. Craig http://enderw88.wordpress.com ------- Re: Measuring and boring holes Posted by: "n2562001" jlkiefferx~xxcharter.net Date: Mon Apr 28, 2008 1:48 pm ((PDT)) Craig: You will need to first determine if you have a boring head/bar problem or a measuring problem. You can check for a measuring problem by measuring an existing hole several times to see if you get the same reading each time. You would normally measure a telescoping gage with a micrometer for accurate readings. Calipers are not that accurate, especially inexpensive digital types. If you have a Sherline boring head problem suggestions can be made to resolve the problem. Jerry Kieffer ------- Re: Measuring and boring holes Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Mon Apr 28, 2008 1:53 pm ((PDT)) Hi Craig: You can't trust the adjusting dial to automatically give you what it says. A good trick is to place your DTI on the cutting edge and then move the radius you need. And that is still not enough to ensure accurate results. Spring cuts help a lot but there is always spring in the bar. As you bore, it is common to get a tapered hole. Smaller towards the bottom due to the resistance of the material. A few spring cuts involving only the lower portion of your bore will bring surprising results. The telescoping gage really requires a deft touch. And the handle should be as vertical as possible. Can't you move the table out of position for the measuring and then return it for the boring? Do you have a lathe? If so, you can make pin gages as you approach your finished bore. Now, I know this post will be followed by Mr. Jerry Kieffer extolling the use of the Sherline Boring Head.... :) More later, Regards, Jerry G (Glickstein) ------- Re: Measuring and boring holes Posted by: "Alan Haisley" alanhyx~xxroadrunner.com Date: Mon Apr 28, 2008 2:44 pm ((PDT)) Craig: When I have used the Sherline boring head, I have had success with the following procedure - starting from a setting and moving to a new setting. First, snug up the boring head dial. Now, with thumb pressure to hold the lower part of the head in, loosen the side bolt, but just enough so that the bottom slide can move. Keeping the thumb pressure on, adjust the dial by the desired amount. Now, still with the thumb in place, tighten down the bottom slide holding screw. While I won't guarantee this method, it seems to provide me with fairly repeatable results; and it certainly can't hurt to try it. You might also try leaving out your step 5; especially if you are advancing the cutter by the same amount on each pass. What should happen then is that the "spring" will be constant from pass to pass. From what I have read, trying to machine out the spring can introduce more variables than it takes out. Try to use the same rotation and feed speeds for each pass. Changing either will change the way the tool cuts. Alan ------- Re: Measuring and boring holes Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Mon Apr 28, 2008 7:01 pm ((PDT)) Hi Craig: One of the most common causes of the erratic results you're describing is poor tool tip geometry. You need to inspect the tool tip very carefully before using it, to be sure it's sharp and has the correct side relief especially in small diameter holes. It also needs to be positioned so it doesn't rub on the sides of the hole. Solid carbide boring bars are my favourite tool for a boring head...I grind my own, but you can get them from Micro 100. Cheers Marcus ------- Re: Measuring and boring holes Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Mon Apr 28, 2008 8:57 pm ((PDT)) I'll check the tool alignment, thanks! Craig http://enderw88.wordpress.com ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Mon Apr 28, 2008 1:53 pm ((PDT)) Hi Craig: How did you determine the overall length is beyond the capability of the Sherline Boring head? To my knowledge, the length of the boring bar determines the capability, within practical limits. I had two Sherline Boring Heads. Didn't like them at all because there is no positive way to drive the moveable part in both directions. Only one because the screw bears on a pin. I made my own boring head. If you go to the Photo Section, and look in the Miscellaneous Album there are three pictures of my Boring Head that were posted by Mr. John Guenther, on October 2, 2004. Regards, Jerry G (Glickstein) ------- Re: Locating scribe marks Posted by: "Craig Earls" enderw88x~xxgmail.com Date: Mon Apr 28, 2008 3:14 pm ((PDT)) The length of the Sherline boring bars is just a tad over 1.5 inches. I looked at the photos of your boring head. How did you etch the marks on the screw? Did you use a dovetail end mill to cut the ways or is there another way? Craig http://enderw88.wordpress.com ------- Re: Locating scribe marks Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Tue Apr 29, 2008 1:27 am ((PDT)) Hi Craig: The screw was cannibalized from a Criterion Boring head, and I built the rest. I just had to engrave in an index mark. The dovetail slide on both parts were milled on the Sherline, and fitted together. I have a second Criterion Boring Head that I machined the O taper and drilled and tapped the shank for the Sherline Headstock. Could be mounted on the lathe with a part clamped to the cross slide. A poor man's Boring mill. Regards, Jerry G (Glickstein) P.S. If you would like dimensions to build your own, just sound off! ------- Need advice on Boring/Reaming on Lathe [sherline] Posted by: "mhjiii" mhjiiix~xxyahoo.com Date: Fri Oct 17, 2008 5:39 pm ((PDT)) I am new to machining and would appreciate some advice. I am making a simple engine from barstock. I need to drill the cylinder in an aluminum block off center and then bore or ream to size. The diameter needed is 0.500", so I will drill to 31/64ths offset in a four jaw chuck. Question 1: Should I ream the final hole or bore it? Question 2: What reaming or boring tool should I purchase for the Sherline lathe to complete the job? I have a boring head and tool for the Sherline mill, but it does not look like the tool is long enough to complete the cylinder. Thanks for your help. ------- Re: Need advice on Boring/Reaming on Lathe Posted by: "DA Dossin" danatlx~xxyahoo.com Date: Fri Oct 17, 2008 8:01 pm ((PDT)) Reaming will follow the existing hole so if the drilled hole is crooked, reaming will retain its "crookedness". Boring will 'straighten' out the hole. Leaned this in the US Navy and heard it from other folks too. Dan ------- Re: Need advice on Boring/Reaming on Lathe Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Fri Oct 17, 2008 8:48 pm ((PDT)) That is true, Dan, and to address the length of the boring bar, "mhjiii" ( name?) should line bore the cylinder... In the mill. In the lathe, bore and then make a mandrel to complete the bore length... (bore from opposite side while cylinder is mounted on the mandrel.) Slight mismatch/step in bore can be corrected by lapping or honing. Jerry G ------- Re: Need advice on Boring/Reaming on Lathe Posted by: "alenz2002" alenzx~xxbellsouth.net Date: Sun Oct 19, 2008 10:36 pm ((PDT)) Hi Maw-jai(?). You might consider boring, reaming and then lapping to final size. For the boring, you needn't buy anything from Sherline. Just grind your own tool from a broken 3/8 drill or equivalent stock. Just square it off on the grinder with a bit of end relief and don't bother with the fancy contours that are in the `store bought' boring tools. Just mount it in the tool holder at a slight angle so that there is a bit of clearance on the left side (so that it doesn't rub the bore) but not so much an angle that it might rub on the right hand side at full depth. Of course it will need to be mounted at the proper height but that shouldn't be a major problem. HTH Al ------- Re: Need advice on Boring/Reaming on Lathe Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Tue Oct 21, 2008 7:00 am ((PDT)) On Sun, Oct 19, 2008, alenz2002 wrote: > Of course it will need to be mounted at the > proper height but that shouldn't be a major problem. One of my very first projects on my sherline was a holder for the boring bars. I started with a 1/2"x1/2"x3" piece of poor-quality hardware store aluminum stock. Filed a bit off of one side until it would just fit in the sherline toolpost. Squared it up end on in the toolpost and center- drilled, then drilled for the shank of my boring bar using the headstock to hold the drillbits (this ensures that the center height is correct. Cross-drill (again using the drill in the headstock method) and tap two holes into the side of it to take grub-screws and you are ready to bore holes. The holes are not actually centered in the 1/2"x1/2" stock, but they line up with the centerline of the headstock nicely, as long as the filed surface of the block faces up. ------- NOTE TO FILE: The following discussion took place on the Yahoo group for Myford 7 lathes (meaning 7 inch diameter swing). Most comments about boring and reaming are applicable or adaptable to the home-sized lathes we use and love. ------- Boring vs Reaming [MyMyford] Posted by: "andyevans_2000" andyevans_2000x~xxyahoo.ie Date: Tue Oct 28, 2008 10:24 am ((PDT)) Can anyone explain the benefits of one over the over? I have to machine a 5/8" bore 3" deep in steel. I have drilled a hole 1/2" in diameter and need to remove the rest to leave a smooth, parallel bore. I don't own any reamers. Regards Andy ------- Re: Boring vs Reaming Posted by: "Cliff Coggin" clifford.cogginx~xxvirgin.net Date: Tue Oct 28, 2008 10:57 am ((PDT)) As I understand it, boring will make your initial hole parallel and concentric but not smooth or accurately sized. For the latter you then need to ream it. Cliff Coggin ------- Re: Boring vs Reaming Posted by: "Tim Ostley" Tim.Ostleyx~xxgooglemail.com Date: Tue Oct 28, 2008 12:27 pm ((PDT)) Dear Andy: An interesting question! Reamers are designed to take a few thou out to leave a hole accurately sized and with a reasonably good finish. Boring is a technique for using a single point tool to make a hole, the accuracy and finish of which is defined by the skill of the operator, the specific technique used and how well the lathe is set up. Assuming we are talking a bout boring in the lathe, you have two basic techniques. Firstly you can hold the work conventionally in the chuck and use a boring tool (look at any tool web site or catalogue to see the shape of this) placed in the normal tool holder. The accuracy of the bore will have two components, the actual diameter of the hole and how tapered it is. The diameter is down to the person on the end of the cross slide - if you wind too much the hole will be over size! The amount of taper is down to the set up of the lathe. If you turn an ordinary piece of steel, about 3 inches long very carefully and then measure it's diameter in two places, two inches apart and divide the difference in diameter by two, you will get a figure for the amount of taper per inch which will apply whether you are boring a hole or turning down a bar. If the amount of taper (there will always be some even if your measuring tools don't detect it) is acceptable for the job you are doing then great, otherwise you need to generate the hole a different way. The second technique is to hold the job being bored on the cross/top slide and move the job rather than the tool. The tool can be a 'between centres' boring bar or a boring head held in the headstock spindle. Both of these will generate a bore that is parallel since the tool is longitudinally stationary and so any twist or offset due to the lathe is constant. Between centres boring bars are difficult to adjust to bore a specific diameter, wheras a boring head is easy but is not cheap. In summary, the worst way of generating an accurate hole is using a twist drill. This can be made more accurate by using a reamer (or D bit) but there is a technique to using a reamer to stop it bell-mouthing the hole. Boring tends to be used for larger holes and can give you an accurate hole with a good finish but once again needs the right approach and tooling. Hope this helps. Tim ------- Re: Boring vs Reaming Posted by: "tr0up" a.troupx~xxemail.com Date: Tue Oct 28, 2008 2:48 pm ((PDT)) Excellent posts above. Just a few more points: 1) Reamers are expensive and conventional reamers are not very versatile (you need one for each nominal size, and even then you will probably have to make the hole first, then turn the other part to fit, as the hole size is fixed). Adjustable reamers are worth considering - you may pick one up second hand for a reasonable price. With these, you can sneak up to a size, taking out minimal quantities each pass. 2) If you stay with conventional reamers: Using hand reamers in a lathe is problematic, and certainly not viable in blind holes; you need a machine reamer, aka chucking reamer. DO NOT ever stop (or, worse, reverse) rotation with the reamer in the hole. 3) Using hand reamers by hand takes real skill if an oval or bellmouthed hole is to be avoided. Using a chucking reamer in a lathe: first check your tailstock barrel is truly concentric and parallel with the spindle A 16mm hole is getting quite large, either way, for reaming in a home workshop situation. 3) Reamers are at their best when you have lots of holes to produce all to the same size - I find them fairly scary for one-offs, as it can take a bit of trial and error to get them cutting well (amount of stock to be removed, speeds, feeds, cutting fluid) and if you screw up (which is quite easy to do) they can make a mess of your hole. Working on your boring skills is likely to be more productive, because they are much akin (and applicable) to turning skills. Without knowing more about what you need to achieve, I'd tend to suggest swinging the work in a chuck and using a boring tool clamped to the cross slide. Easiest way to make a boring tool is probably to drill a cross hole in square MS for a small round HSS toolbit, and either silver solder it in place (at the end opposite the cutting tip) or tap a hole in the end of the square to nip it up. Make sure when you sharpen the tip that it will clear the arc of the work, not for the finished diameter but for the starting one (ie 1/2" in your example). An easy way to check this is to offer up a washer whose ID is the size in question. ------- Re: Boring vs Reaming Posted by: "andyevans_2000" andyevans_2000x~xxyahoo.ie Date: Tue Oct 28, 2008 3:55 pm ((PDT)) Thanks all for the advice - I appreciate it. I have just been practicing boring with the work in the chuck and a boring tool clamped in the clog- heel toolpost. Results were mixed, there was a lot of squealing (from the work during boring and from me - I slipped when sharpening the tool and it went straight through my nail and finger!). Also had a problem with the tool slipping in the toolpost. I have a 4 way toolpost but the boring tool I have cannot be raised to centre height in it. I will keep on practicing before tackling the next stage of the travelling die-holder I am making. Regards Andy ------- Re: Boring vs Reaming Posted by: "tr0up" a.troupx~xxemail.com Date: Tue Oct 28, 2008 10:28 pm ((PDT)) Clog Heel - Nice coinage ! or if it's not original, I haven't heard that one ... but if the clog fits .... ! The CH toolpost is much maligned (and to my thinking, misundertood). It grips reasonably well, provided: 1) All mating surfaces (top and bottom of tool and packers, toe clamp surface of CH) are FLAT. You may need to draw file the latter items, and lick the former on a grinder. They need not, however, be strictly parallel. 2) It is correctly adjusted for height. As a youth I would crouch down and try to eyeball this, but I have since got more cunning: if you get it close for height, then snug the hex nut down by hand, you'll find you can wiggle the tool shank about its long axis. Check which side is the loosely clamped side, and which the clearance side. Now adjust the knurled Stilleto Heel Jack (think stylish Dutch Missen) until you judge there to be the same amount of twisting slack, but clamped on the other side. The optimum adjustment will be halfway between the two. 3) There are various tricks for increasing the coefficient of friction at each interface: chalk is one, paper another (I find the latter a bit fiddly in this particular instance). In the rare situation where I get slippage, I just swipe each face with a stick of chalk. (NOT soapstone, as used in lieu of chalk for marking out welding jobs.) If I still get slippage with a boring bar, it usually indicates I've got the angles wrong. 4) If you get squeal, and it's not you, it means the shank of the boring tool is vibrating in a resonant way. Assuming the tool angles are suitable and the cutting zone razor sharp: Try changing (usually reducing) speed, make sure you have the minimum possible overhang and that the shank is as big as feasible, and on large jobs it can be worth wrapping the shank with something heavy like solder. On very big boring bars, it's often a case of hanging a few bags of shot on the shank, but I've not seen that done in a Myford ! If the workpiece is thin-walled, it can help also to wrap something tightly around the OD. I've had good results from 5mm nylon cord. You'll need to use electrician's tape to finish off, so nothing can come loose. I've recently got my 'big' lathe going, (a recently acquired slant bed Willson) and tried a test bore in steel, about 100mm inside diameter. I cheated and used a tipped boring bar of decent proportions. I started at about 250 rpm, which is about four times the speed I'd use in the Myford for boring a hole this big. I bored an inch deep and the finish looked good, no drama, so I changed up one speed and bored a little further... each time I sped up the finish got better -- and this remained the trend until I was on top speed, at nearly 1000 rpm! The finish was really good, and the cut was quiet. Luckily there's an auto trip on the longitudinal feed, otherwise it would be scary heading towards the chuck at what would be a screwcutting traverse rate on the Myford. However the Myford is still the most prized and pampered machine in the shop. ------- Re: Boring vs Reaming Posted by: "DA. Forsyth" notLeftBehindx~xxiwr.ru.ac.za Date: Wed Oct 29, 2008 2:18 am ((PDT)) > 1000 rpm ! The finish was really good, and the cut was quiet. On 29 Oct 2008 at 9:11, alan4227 murmured decisively: > That's amazing!. My rusty maths says that 1000rpm is about 1000ft/min > cutting speed - in steel. Does this mean we should forget about the > recommendations in Sparey, Wright, etc. to turn steel at 80 - > 100ft/min? Or do they only apply to light lathes like Myfords? it applies to the tipped tool,mostly. > I presume you could not have used that sort of speed with an HSS tool. I have taken 0.1 inch cuts, sometimes more, in steel, at 600rpm, on my ML7, with HSS. But with very slow feed rate. Depends a lot on tool geometry. > > However the Myford is still the most prized and pampered machine in > > the shop .... I should hope so! Otherwise you might have to resign from this group. David http://iwr.ru.ac.za/~iwdf/ [and in a later message David wrote:] For some extra accuracy you can apply a little trigonometry. (You do need sharp HSS tools for this, since the cut is shallow.) You can set the topslide to 5.6 degrees (the mathematically inclined can refine that figure for us, I don't feel like bending my brain right now) which gives 1 thou infeed for every 10 thou fed on the topslide; or 1/10 thou for every thou fed. I have my topslide set to about this angle all the time, and use the fine infeed quite often. It works well for getting that last skim off to get the bearing to fit etc. Just watch out for the rough burr edge which may prevent a fit when in fact the size is right; deburr before test fitting. ------- Re: Boring vs Reaming Posted by: "tr0up" a.troupx~xxemail.com Date: Wed Oct 29, 2008 4:01 am ((PDT)) Sparey et al were on the button, for HSS in a Myford... A rigid lathe (both the spindle and the bed/carriage system) is an essential pre-requisite for getting modern carbide tooling up into the zone where it performs as designed, and for some reason the difference is particularly marked for boring tools. (I have long been aware of this as I've put in a few hours on heavy industrial lathes, but I've always been rather circumspect using other peoples' gear.) One of the benefits of very high surface speeds is that the heat is localised to the chip. This means you don't need coolant (in fact, it's a bad idea because of thermal shock). With CBN inserts (hardest tip material short of poly-crystalline diamond) on a sufficiently rigid machine, even hardened tool steel can be turned at 500 surface ft minute, with a finish comparable to grinding. If you slow down too much with hard material, you get into problems with tip breakdown, because the heat of the chip doesn't propagate far enough upstream to ensure the material is annealed back to 'turnable' hardness before it gets to the cutting tip. Getting back to the topic, I think perhaps a boring tool exaggerates the advantages of carbide in a rigid setting because its proportions make it such a 'resonator'. Consequently, it amplifies any perturbations arising from the slightest vibration in the underpinnings, which a less springy tool would not be bothered by ... not sure if I'd take a bullet for this theory, or swear a deposition to that effect, but I'd certainly utter it in a pub. What is certain is that a Myford (except maybe the 254) relies on very sharp tooling. By this I mean that when you look along the front cutting edge, the top and front faces need to run as near as possible to the edge before they start to 'wash away'), and the same with the side (leading) edge. It also requires small tip radii (when you look down on the tool, at the junction between front face and side face. A carbide tool with a greater tip radius than 0.5mm needs to be used with discretion rather than valour, on a smaller Myford. Carbide tools are inherently brittle, and do not take kindly to such 'pointy-nosed' geometry (which in the case of sharpness, requires the application of a diamond hone or wheel. Nor do they enjoy being deployed on a resilient machine, so a Myford will not usually give of its very best with carbide tooling. However for turning hardened (or severe work-hardening) or some types of abrasive materials, parting, and other specialised applications, carbide definitely serves a purpose on a Myford 7. ------- NOTE TO FILE: If you are interested in achieving an interference fit, read a conversation about interference fits in my file "Turning Tips for Metal" starting with the message: Sizing a part to be heated [sherline] Posted by: "charlesdewen" charlesdewenx~xxyahoo.com Date: Thu Feb 19, 2009 4:04 pm ((PST)) If you go too far when lapping or reaming or boring a part for an interference fit and the fit is loose, the following idea may save the part. See my file "Lapping and Reaming" for the message: Re: Problem with an interference fit [sherline] Posted by: "charlesdewen" charlesdewenx~xxyahoo.com Date: Wed Feb 25, 2009 8:11 pm ((PST)) ------- [Boring How-To Tip] Learning trick [posted in sherline group] Posted by: "Charles Fox" cafox513x~xxverizon.net Date: Wed Jun 24, 2009 9:55 am ((PDT)) Having trouble figuring out exactly what a boring bar is doing? Try it out on Lucite. I just did that, because I wanted something out of Lucite, then noticed you can follow the path of the tiny point through the material. Very instructive. ------- boring technique (lathe) [taigtools] Posted by: "Ken Cline" clinex~xxfrii.com Date: Tue Sep 1, 2009 9:31 am ((PDT)) I've been using my lathe now for a while without any instruction and would like some advice on boring. I start with a 3/8" twist drill (the maximum size of my tailstock drill chuck), but then I'm not sure of the best technique. The Taig boring bar (from set #1095) seems to be too large for expanding the hole directly, so I sweep across the face (of what will become the hole) working my way into the part until I have a hole big enough to cut with axial movements of the boring bar. I keep thinking there's got to be a better way. Any recommendations? Is this simply a matter of needing different boring bars, or will different techniques work? In case it matters, I've been working with a variety of materials from ABS and delrin to 6061 Al and 1018 steel. The steel was particularly perplexing - I wanted a hole only slightly larger than 3/8, but made do with the drilled hole on the assumption that I needed either a smaller boring bar or larger drill bit. Thanks! ------- Re: boring technique (lathe) Posted by: "Nicholas Carter and Felice Luftschein" felicex~xxcasco.net Date: Tue Sep 1, 2009 9:50 am ((PDT)) It's really easy to grind a boring bar - just start with a blank 1/4" toolbit (or the other end of any of the toolbits that you have) Copy the Taig boring bar but reduce the shank and head size, and radial clearance. See our homepage at www.cartertools.com/nfhome.html ------- Re: boring technique (lathe) Posted by: "deanofid" deanofidx~xxyahoo.com Date: Tue Sep 1, 2009 9:59 am ((PDT)) Ken, the Taig boring tool is too big start the cut in a 3/8" hole, as it seems you've found out. When I need to bore with a starting diameter as small as 3/8", I use a smaller boring tool. I make mine out of 1/4" HSS tool bits, ground to a similar shape as the Taig tool, but scaled down to a size that will cut the bore without dragging on the inside of the hole. You can also get larger drill bits that have a cut-down shank to fit into your drill chuck, and start with a larger hole to begin with. Dean ------- Re: boring technique (lathe) Posted by: "Ken Cline" clinex~xxfrii.com Date: Tue Sep 1, 2009 10:49 am ((PDT)) Thanks guys! Knowing I need a smaller boring bar helps a bunch. Due to the amount of relief needed along the tool shaft, it seems best to start with new blanks. At least for those tools ground for deep boring. I'll also look for a reduced shank bit for roughing large holes. 1/2" seems perfectly reasonable for a 500RPM Taig lathe, but I have no idea how big I can go. Can you reliably drill on the lathe with larger bits? ------- Re: boring technique (lathe) Posted by: "deanofid" deanofidx~xxyahoo.com Date: Tue Sep 1, 2009 2:19 pm ((PDT)) Yeah, I think you would do best to start with a fresh 1/4" HSS square bit to make a new boring bar, Ken. I have quite a few of them that I ground from basic tool bits. I start by grinding away a half round section between the ends of the tool bit. Leave one square end long enough to mount in the tool post, and on the other end leave about 1/4" of it square, to start with. When you get your half round section down to size you can grind the smaller square end to your cutting profile. You can make them as small as you want, but as you make the shaft part smaller the possibility of chatter and tool breakage goes up. I don't know how large a hole you could expect to drill on the lathe. I can't recall drilling larger than 1/2", but that doesn't mean you can't go larger. You'll have to try it. You'll know when you get too big. The bit will chatter and howl until you can't stand it any longer. Most hardware stores have reduced shank drill bits that you can buy as singles or sets. Dean ------- Re: boring technique (lathe) Posted by: "Don Rogers" Donx~xxCampbell-Gemstones.com Date: Wed Sep 2, 2009 12:44 pm ((PDT)) The home made boring bars from HSS bits is good advice. I've got them down to the size that will fit a 1/8" hole. Just remember, the smaller the size, the shorter the depth you can bore. Probably around a 4 to 1 ratio on the really small ones. Very light cuts are in order also. Watch the heel clearance, tool height is really critical on the smaller boring bars. I like to set my small boring bars up about 5 degrees off parallel with the ways. Just watch the back of the shank as you are getting into the hole. On the drilling, I've drilled up to 1" holes on the lathe using a ½" drill chuck and Deming drills. As posted, the noise and vibration gets to be quite bad. Start with a small drill and step your way up, reducing speed every now and then. The Deming drills, at least the ones I have, have an aggressive rake and especially on the plastics, it is best to grind the cutting edge to about 85 degrees so it doesn't snag the plastic and try to pull through. Also, drilling with a 1" drill will probably give you a sorta round hole up to about 1 1/8" diameter, especially at the entry point. It would be a good idea to drill small, leaving a lot of boring stock and then bore out to finished size rather than drilling for just a cleanup bore. Also leave some material on the face so you can clean up any chatter marks from the large drill. Drilling this size is really pushing the limits of the Taig. Make sure the belt is very tight to prevent burning the belt in the event of a drill lockup. The other recommendation when drilling something this big is to use the four jaw chuck; the three jaw scroll just doesn't have enough strength to hold stock that big with the load the big drill will inflict, especially if it snags. Don ------- Re: boring technique (lathe) Posted by: "Jeff Demand" jdemandx~xxgmavt.net Date: Wed Sep 2, 2009 1:16 pm ((PDT)) Taps can be reground with minimal labour to make boring bars. Maybe grind a few teeth off but usually not much more. Granted it will not work as a tap anymore. jeffD ------- Re: boring technique (lathe) Posted by: "Shad" shendersonx~xxthegeekgroup.org Date: Wed Sep 2, 2009 1:32 pm ((PDT)) Now that is something I hadn't thought about! I've ground old broken drill bits down to use as boring bars. I've ground 'em from 1/4" tool blanks, and I've even used one of my single- flute endmills for a tiny boring bar once when I was in a pinch. But I never thought to use a broken tap. Usually when I get a broken tap, I chuck it up in a drill and grind the broken end flat to make a bottoming tap out of it. Shad H. ------- Re: boring technique (lathe) Posted by: "Jeff Demand" jdemandx~xxgmavt.net Date: Wed Sep 2, 2009 1:53 pm ((PDT)) Shad, I had forgotten about the end mill trick, some grinding might still be needed unless the pilot hole is large enough for you to angle the bit. The tap trick will also work for internal threading, nice 60° angle. Sometimes it works but most of us have plenty of broken tools :-) jeffD ------- Re: boring technique (lathe) Posted by: "rx~xxshred2.net" Date: Wed Sep 2, 2009 1:45 pm ((PDT)) FWIW I've used small end mills as boring bars in a pinch as well -- set the working flute as you would a normal boring bar. ------- Boring Bar in Tailstock [MyMyford] Posted by: "Rodney Wilson" rodney.j.wilsonx~xxbtinternet.com Date: Fri Oct 9, 2009 1:38 am ((PDT)) When you use a boring head, in the tailstock, for whatever reason how do you: 1 ensure it is horizontal 2 ensure it stays that way 3 cope with radial backlash Help appreciated Rod ------- Re: Boring Bar in Tailstock Posted by: "Ken Strauss" ken.straussx~xxsympatico.ca Date: Fri Oct 9, 2009 7:59 am ((PDT)) Depending on what you are doing being accurately horizontal may not matter. Most boring heads have at least two holes for the cutting tool so you could insert dowel pins in each and level the head using a machinist's level resting on the pins. I haven't done so but some suggest cutting a small notch in the face of the TS ram and inserting a suitably positioned taper pin into the boring head's MT shank. A normal dog tightly clamped to the boring head's body would be another option. I've simply firmly seated the MT shank prior to use and have not had a problem. If by "radial backlash" you are thinking of rotation of the TS ram, why not just use the lock? ------- Boring head bit [myfordlathes] Posted by: "andyevans_2000" andyevans_2000x~xxyahoo.ie andyevans_2000 Date: Tue Feb 2, 2010 3:32 pm ((PST)) Hello all - not a myford question but I am sure someone can help. I am trying to grind a 1/8th inch round hss blank to form a boring bit to insert into a 1/4 inch bar for my boring head. The hole in the bar is at 90 degrees. My question is what angles do I need to grind on the bit to get the best results? Would I be better making a new bar with the bit hole at 45 degrees? Andy ------- Re: Boring head bit Posted by: "Alan Moore" a.j.moorex~xxbtinternet.com alan4227 Date: Wed Feb 3, 2010 5:23 pm ((PST)) Hi Andy, My first thought would be that if the hole is at 90 degrees you could grind the bit to the same angles you would for a left hand turning tool, boring from right to left being the same as turning from left to right. You are likely to have to increase the front clearance, though, to prevent the bottom of the bit rubbing on the workpiece. As for a new bar with a 45 degree hole, the only advantage of this is being able to bore down blind ended holes. If this is not a requiremment you could carry on with the bar you have. Regards, Alan ------- Re: Boring head bit Posted by: "andyevans_2000" andyevans_2000x~xxyahoo.ie andyevans_2000 Date: Thu Feb 4, 2010 4:47 am ((PST)) Thanks Alan -- will try that tonight. For some reason I always have problems visualizing the 3D angles needed when grinding tools. Andy ------- Re: Boring head bit Posted by: "MikeD" durnfjmx~xxaol.com durnfjm Date: Thu Feb 4, 2010 5:36 am ((PST)) With most lathe and boring tools, the *actual* angle is usually far less critical than getting the edge really sharp. Depending on what material you are boring, you may find that a round nose tool with just a little top rake (or no top rake for brass or bronze) and plenty of front clearance so that the tool clears the bore -- works just fine. When you have got the shape right on the grinder, stone the cutting edge with an Arkansas stone or diamond hone, and make sure it is properly keen. You'll have to work out what speeds and feeds give you best results by trial and error, but I am inclined to start a bit faster than the text- books say, and take fine, shallow cuts. MikeD ------- Re: Tiny boring bar [sherline] Posted by: "Stephen B Brown" n8hfix~xxbellsouth.net Date: Wed Apr 7, 2010 7:00 pm ((PDT)) > Tiny boring bar Just started work on an Elmer's 23 Tiny. Need to drill and bore the cylinder, but my boring bar for the lathe is waaaaaaay too big to fit in a 3/16" cylinder bore. Guess that means I've got to take a blank hss bit and the grinder and make my own boring bar. Anyone know the url to a picture of such a small boring bar, so I can see what I'm trying to accomplish? Anyone got any tips for boring small cylinders like this? < I made a D-bit out of some drill rod for this. Drilled undersize (and underdepth) with a twist drill, then used the D-bit to ream to size and square the bottom of the hole. Do the cylinder first, then turn the piston to fit, you don't have to get exactly on the drawing dimension, just as long as they fit each other. Stephen Brown ------- Re: good boring bar [sherline] Posted by: "Ian Newman" ian_newx~xxyahoo.com Date: Sat Jun 4, 2011 1:58 pm ((PDT)) Hi. There is no big secret to the profiles for boring bars, but the exact shape depends on what you are trying to do. There are three distinct types of boring bar profile and the three tools are designed to do different jobs -- you will not get the best results if you use the wrong tool in the wrong application. To identify the type of boring tool it is best to look at the tool tip from above and look at the cutting edge formed across the end of the tool. The cutting edge may go from the tool tip and slope away from the headstock (positive lead), it may slope from the tip towards the headstock (negative lead), or it may be at almost 90 degs to the lathe axis (zero lead) -- see the picture here: http://www.criterionmachineworks.com/Graphics/leads.gif Positive lead tools are designed for facing -- i.e. to cut from the centre of the bottom of a hole towards the outside of the bore. They are used to produce flat bottomed blind holes or shoulders (in bearing housings, etc.). You should never use a positive lead tool to cut down the length of a bore. Boring tools are (by nature of the work they do) relatively thin for their length, so they tend to be flexible. If you cut the side of a bore with a positive lead tool the tip tends to dig in and the tool bends away from the axis of the bore which produces a bore that is narrower at the entrance and wider inside. To cut the side of a bore the best tool shape has negative lead. This can only be used if the tool can pass right through the bore as the front end of the tool is in front of the cutting tip. The slope of the cutting edge flexes the tool towards the axis of the bore producing a hole that is narrower inside than at the entrance -- repeating the final cut several times at the same setting will correct for this "spring". The zero lead tool is a compromise -- it is not the best profile but it lets you bore the side of a blind hole, or bore to a shoulder. These tools are normally 91 degrees to the axis rather than the theoretical 90 degrees suggested by the name "zero lead". Personally, I have never found the need for a 91 degree zero lead tool, but there is a picture of one here: http://www.greenwood-tools.co.uk/ishop/728/shopscr22.html A picture of a couple of my positive lead tools is here -- the top tool is ground from a standard 6mm HSS blank: http://i219.photobucket.com/albums/cc210/ian-new/boring%20bar/plan2.jpg And here is a pic of one of my boring bars with negative lead: http://i219.photobucket.com/albums/cc210/ian-new/boring%20bar/plan.jpg Ian [in a later message Ian wrote:] Drilling and reaming is not an alternative to boring: A twist drill always produces a hole that is bigger in diameter than it is supposed to be, in the wrong place, not circular and following a curved path (of course that trick is to make sure that the errors just listed are smaller than the required tolerance). Reaming a drilled hole will remove the lobes created by the use of a twist drill and so makes the hole round, it will also improve the dimensional accuracy. A reamer, however, will follow the path of the hole and so it will not correct the axial truth of the hole and it will not orrect any error caused by the drill starting slightly off of its proper location. Boring allows for accurate hole positioning (especially if the work is set up using toolmakers buttons) and creates holes that follows a straight path. ------- Setting Bore Radius [sherline] Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Tue Dec 20, 2011 7:51 am ((PST)) Hello Group, I think I recall that a short while ago someone was asking about setting up the boring head. Happen to be doing this yesterday so posted some photos. See 3 shots begining with: http://groups.yahoo.com/group/sherline/photos/album/937902184/pic /1730553101/view boring the casting for a PM Research #5 engine. When using the boring head, always take a first cut, measure the result, and adjust incermentally, since there's always going to be a good deal of tool spring. Plan ahead to make each increment close to the same, especially the last 2, so that the spring is fairly constant. Note also the fairly elaborate fixturing to ensure the casting is held firmly and properly datumed. Was easily able to achieve the 0.750 +.002 -.000 specified. Best, David Clark in Southern Maryland, USA ------- Re: Setting Bore Radius Posted by: "shipmodelmaker1931" shipmodelmaker1931x~xxyahoo.com Date: Tue Dec 20, 2011 8:01 am ((PST)) Hi Dave: What do you do to control taper and bellmouth that usually occur when boring in spite of spring cuts? Also, what do you use to measure the bore diameter? Regards, Jerry G (Glickstein) ------- Re: Setting Bore Radius Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Tue Dec 20, 2011 12:22 pm ((PST)) Hello Jerry and All, Jerry of course knows the answers to these questions and is prompting me to elaborate for the newer hands. OK. In this instance, no additonal controls were needed. Staying within a .002" zone of tolerance in a bore only about 1/4" deep was no sweat on a Sherline. Measurement to the required accuracy was easily accomplished with a telescoping gauge and micrometer. (I would NOT rely on calipers to that tolerance.) Matters were also facilitated by the fact that PM Research castings are very high quality grey cast iron, and machine beautifully -- very consistant. It would have been more difficult in a tough material: some stainless alloys, or brass, for example. In such cases, or for a longer bore, or tighter tolerance, the next step is reaming, and the next, lapping. Mill and/or boring head for location -- ream and/or lap for form and size. The next step in measuring is a bore micrometer. The ultimate step is a jig grinding machine. Another error of form to watch out for when using such a small boring head on a light machine like a Sherline is due to harmonic movements in the tooling or setup. A boring tool, or an insufficiently rigid setup, may flex rythmically and cut a cylinder that is lobed. This may not be detectable by measuring diameters only -- sweep the entire inside of the cylinder with an indicator to check form. When I get to boring the steam piston cylinder, I will certainly lap it for the closest possible fit with the piston. Thank you Jerry, best to all, David Clark in Southern Maryland, USA ------- Re: Setting Bore Radius Posted by: "shipmodelmaker1931" shipmodelmaker1931x~xxyahoo.com Date: Tue Dec 20, 2011 12:32 pm ((PST)) Well, Dave, you have covered it all! Thank you, and have many Healthy, Happy Holidays, Regards, Jerry G (Glickstein) ------- Re: Setting Bore Radius Posted by: "Ian Newman" ian_newx~xxyahoo.com Date: Tue Dec 20, 2011 1:33 pm ((PST)) Hi, A useful bore comparator is quite straightforward to make - see the pics in the album "Bore Gauge" for one that I made. The design is not mine, it is based on some notes I made of an article in Model Engineer Magazine (date and issue unknown). Pics 1 and 2 show the range of the gauge 1/4 to 2 inches - the arms can reach a depth of about 1.5 inches down the bore. Pics 3 to 6 show the component parts and the assembly of the gauge. Pics 7 and 8 show how I profiled the ends of the moving arm. First file the probe tip to shape, then use a mic to measure 10 thou increments of probe travel, milling the DTI arm at each 10 thou step. Pic 9 shows an alternative tool which is much easier to make and just as accurate. Ian ------- Re: Setting Bore Radius Posted by: "ED MAISEY" holmes_ca_2000x~xxyahoo.com Date: Tue Dec 20, 2011 3:14 pm ((PST)) David, A question, are you using the dial indicator for increasing a cut? and is that for the final cut?, just curious, Edmund ------- Re: Setting Bore Radius Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Tue Dec 20, 2011 3:36 pm ((PST)) Hi Ed, Yes. I make a series of cuts to get within around .030 of the final size. Then use the indicator to verify the adjustment as I increase the radius of the boring head by 0.010. Run the bore in and back out. Check to verify that the hole size is actually increasing by the amount set. Repeat 'til the final cut achieves the desired size. The point is consistancy. Keep every variable: speed, feed, depth of cut, as uniform as possible as you incrementally approach the goal, with each pass checking the adjustment of the boring head with the indicator, and the resulting hole diameter with the telescoping gauge and micrometer. DC ------- Re: Setting Bore Radius Posted by: "ED MAISEY" holmes_ca_2000x~xxyahoo.com Date: Tue Dec 20, 2011 4:21 pm ((PST)) David, thank you and I like your idea very much, excellent, being in the profession I have always used the boring tool by backing off and resetting in a smooth turn when increasing a cut especially for the last few thou together with repeatable cuts at the same setting, but that was always with quality tooling, it's a bit different when using tooling that is doubtful regarding the quality of workmanship from some countries, so I will be using your method in future. Edmund ------- Taig boring head [taigtools] Posted by: "Jake Horky" jacob.horkyx~xxgmail.com Date: Sat Mar 3, 2012 8:26 pm ((PST)) Can anyone comment on the boring head options for the Taig mill? I know of the Taig offering, the Little Machine Shop head w/ adapters, and the Sherline. I like the LMS option because it has the graduated dial, but it ends up being twice the price as Taig's after you add the ER-16 adapter and some boring bars. Is the extra cost worth it? Can anyone compare the two? I need to make a couple 5/8" diameter holes for press fit bearings, and I figure I should invest in a boring head over a reamer and pilot drill. I've been wanting to make one but something came up and I have to get some accurate holes made asap. Thanks in advance! ------- Re: Taig boring head Posted by: "Dean" deanofidx~xxyahoo.com Date: Sat Mar 3, 2012 10:19 pm ((PST)) Jake, if you need these holes asap, you will probably do better by getting a -.001" reamer. I realize you'd like a boring head. I'm not trying to talk you out of that. Just for the job at hand, a reamer will get it done at one pop, no messing around. For a boring head, I'd recommend one that keeps the tool as close to the spindle as possible. I haven't used the one from Taig. It seems a little light and a little long. Nick did a short write-up about it on his webpages, and I notice he got some chatter in all the cuts he showed. I don't believe that chatter was caused by the Taig milling machine. It's plenty rigid to prevent that. I would put it down to the boring head design. Maybe he will comment more about it here. I have one that I made from prints by Stephen Campbell. It mounts directly to the Taig mill spindle and is quite short. It's also made from steel. I've done 2" diameter holes with it in steel plate and had no chatter. It's simply a good design, and you can find prints for it on my website, along with a build article I did a few years back. http://www.deansphotographica.com/machining/projects/mill/bor ing/boring.html If you don't wish to make one, try to find one that is compact in length that will fit in a 3/8" ER collet. Dean ------- Re: Taig boring head Posted by: "jakehorky" jacob.horkyx~xxgmail.com Date: Sun Mar 4, 2012 6:00 am ((PST)) Thanks Dean - using a reamer to get them done makes the most sense. The part I didn't mention is that I don't think I have a means to make the pilot hole to begin with. My little 9" drill press can't take a bit that big, let alone drill it straight and without awful chatter. I've struggled trying to drill a 12.5mm hole for a 1/2" ream in the past. I suppose I could mill the hole via CNC instead. If this is acceptable then I think I'll try it. It sounds like the LMS head would have have advantage of being shorter and stiffer, since it's steel and screws directly on the ER-16 threads. BTW, I've read your boring head build nearly a dozen times and really appreciate the time you spend to document your excellent work... I should have built it a while ago when I didn't need it! Thanks! ------- Re: Taig boring head Posted by: "Chris Shafer" shafercrx~xxyahoo.com Date: Sun Mar 4, 2012 4:08 am ((PST)) Jake; On a hole that small personally I would go with an adjustable reamer. Remember the dials on boring heads are just a guide you still have to verify. With the adjustable reamer it is possible to sneak up in very small increments. Chris ------- Re: Taig boring head Posted by: "jakehorky" jacob.horkyx~xxgmail.com Date: Sun Mar 4, 2012 6:07 am ((PST)) Good suggestion, I've used a 1/2" adjustable reamer in the past. In this case I'd like to try a chucking reamer, but now I wonder if my drill press is even tall enough, so I'd probably have to get a tapered/ adjustable reamer and do it by hand. However, as I wrote in another reply, I don't have a good way to drill the pilot hole to begin with, unless CNC milling it with a 3/8" endmill is good enough. Thanks! ------- Re: Taig boring head Posted by: "alighazizadeh" alighazizadehx~xxaol.com Date: Sun Mar 4, 2012 7:13 am ((PST)) Hi, This is link to a small 35mm boring head on a 10mm shank which fits the taig er 16 head, the company is in the UK but I am guessing that the LMS offering is similar. The only draw back is that it only takes 8mm shank tooling and I can not find any with braised carbide tip in the Uk. http://www.rdgtools.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fw ww%2erdgtools%2eco%2euk%2facatalog%2fBORING_HEADS__NEW__1%2ehtml&WD=sm all%20head%20boring&PN=10mm_SECTION%2ehtml%23a2331#a2331 Regards, A.G ------- Re: Taig boring head Posted by: "taigx~xxste-marie.org" Date: Sun Mar 4, 2012 10:27 am ((PST)) I've not had the best luck with the Taig head. I was boring an interrupted cut for a two-piece lathe dog and the shank cracked. I sent it back to Taig at Nick's suggestion so they could improve the product. Taig very graciously replaced it--I hadn't asked them to, what with the interrupted cut and all. I think a concentric adapter without a shaft that screws directly on the spindle and into the head would be a better design. I believe A2Z sells one with a 7/8" thread that will screw into the back of standard small boring heads. ------- end mill/boring tool [atlas_craftsman] Posted by: "Doc" n8as1x~xxaol.com docn8as Date: Mon Oct 15, 2012 7:39 pm ((PDT)) FWIW ... end mills, chipped or broken make VERY ridgid boring tools, more so than boring bars & bits ... 2 flute ones require less grinding ... square off the end & rotate the good flute to a 9 oclock position ... the flute is a built in boring edge w back rake & a tad of side rake... you may want to bevel the end away some & may need to gain clearance by grinding the back of the flute starting low to retain the edges for future sharpening...in which all you need to do is rotate the endmill slightly. best wishes doc ------- NOTE TO FILE: I normally place a conversation into only one file here, the one I think most suitable for the particular topic. But the following discussion involved threading, and making an Atlas backplate [or any other brand's for that matter], and doing it with a boring bar. So it ended up in all three files. ------- Boring bar deflection [atlas_craftsman] Posted by: "geoffrey_in_siam_atlas_12in_3991" lovex~xxcvbt-web.org Date: Fri Mar 1, 2013 9:04 am ((PST)) We're making a backing plate for a 4-jaw chuck that I bought. I have to bore and thread 1.5" 8tpi threads. In making trial cuts on a test piece I've come across some puzzling things: Boring, we dialed in .150 on the cross feed and get .003" Threading, we dialed in on the compound rest .067" and got less than .010" Our boring bar is about 1/2" in diameter and 6" long. We mounted a linear dial indicator on the carriage and put the tip on the boring bar about 2" from the tool post. It seems that the boring bar is deflecting. When we set it up for real then we can grip it shorter. As we cut threads we think that the deflection will become greater. So, how can we measure to know when we have sufficient depth of thread? We don't have a male bolt handy. ------- Re: Boring bar deflection Posted by: jmartin957x~xxaol.com Date: Fri Mar 1, 2013 12:43 pm ((PST)) Use the largest bar that will fit the bore, and choke up on it so that you can cut just as far as you have to. No further. It should be sharp, and cutting. Not rubbing. Set it at center height or a bit above. Even if you do everything right, you'll still have to take a couple of "spring cuts", without changing the cutting depth, to take out the slop and windup in the system. Silly question, but you are taking out the backlash in both cross and compound feed screws in the cutting direction - outward - right? John Martin ------- Re: Boring bar deflection Posted by: "Doc" n8as1x~xxaol.com docn8as Date: Fri Mar 1, 2013 12:45 pm ((PST)) if you are using the lathe that the chuck is intended for, you must EITHER make a copy of the spindle thread to check your thrdng progress, OR mount the back plate on a face plate ..then you can remove the face plate w/ back plate attached to check progress & then replace w/ out needing to pick up the thread...you are threading to fit, and NONE of the current depth of thrd specs will be correct ...you need to cut a V thrd, not some other stndrd.....you thrd to FIT on these spindles & on most home shop items ..if you doubt that, i will GLADLY sell you a 1-1/2 & 8 new tap for $20 + shpg. if you are inexperienced in boring /thrdng, PRACTICE on scrap first ... all boring bars flex ...just a question of how much, (doc, extension, diameter, grind etc) ....use a sharp pointed HIGH speed bit ....carbide cannot be made as sharp & requires more FORCE to cut, hence more flex... books show a rounded point ..forget it ...you want a sharp point w/ back rake & PLENTY side rake .for a real smooth finish; either angle the bit as flat as opossible w/ out chatter OR grind a 1/32 flat & take cuts under 5 thou (real smooth not needed to thread on)..these are light machines (plenty flex w/ using turning tools also) & until you really know where you are, 20 thou doc is plenty ...too fast a feed, & the bar will spring away ......stone your grind, makes a big difference....i use at least a 3/4 bar w/ bit on the end for 1-1/2 thrd.....i assume you are using a 1/2 bar w/ a small tool bit at the end???? you can still make it work, just lite cuts. fifty years ago w/ a 6x18 i bought the catalogue boring tools & cud not figure out for a LONG time why i cud not bore ...turns out the tools were not HARDENED ...experience wud catch that right away ...but as a beginner, it drove me nuts. oh yeah, dont forget to compensate for the back lash on your compound / x feed ....if you have not dialed it out, you can put on 20 thou or so & not move the bit !!!!!!! & just for the record i have cut more than a dozen back/face plates, finally on the last one i made a dummy spindle. best wishes doc ------- Re: Boring bar deflection Posted by: "cliff" kenx~xxucsp.com Date: Fri Mar 1, 2013 1:20 pm ((PST)) Make a male bolt first. You can check it as you make it by using a chuck or other 1.5 x 8 threaded part as go/no go. Then use the bolt as the go/no go for the back plate. The male part is much easier to make (external threads), and I doubt you will have great joy making the internal threads without having a go/no go test method. ------- new article: Boring Bar Thoughts [atlas_craftsman] Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Tue Jun 4, 2013 12:51 pm ((PDT)) I've been using my lathe a lot over the last month. All of the calculator work needed to figure depth of cut in order to achieve the desired ID or OD got to be tedious. So I started to develop a program to do it for me. This program was first written for an HP-35s calculator but I quickly ran out of memory. Then I bought a used TI-83 Plus for $40 and re-coded the program for it. The program grew and grew until it became obvious that I needed to better understand exactly how a boring bar behaves. My thoughts on boring bars are presented in this article along with my shop experience with the program in boring a 1.000" hole. If you are interested, go to http://rick.sparber.org/bbt.pdf A companion article detailing the program will be out soon. I will also publish a file which can be uploaded into a TI-83 Plus so you don't have to manually type it in. Your comments and questions are welcome. All of us are smarter than any one of us. For the full index of my articles, see rick.sparber.org. Rick ------- Re: new article: Boring Bar Thoughts Posted by: "Scott Henion" shenionx~xxshdesigns.org Date: Tue Jun 4, 2013 1:21 pm ((PDT)) A good description of the flex of boring bars and the effect. Rather than calculate desired DOC, I do rough cuts until I get within 1 rough cut size. Then i do a few passes (usually 2 both directions) without advancing the cutter. Measure the diameter and then i know how far to go. Advance the cutter just under the distance and do passes until no material is removed. Then if needed, advance the cutter the distance left and do 2 passes. The key is doing some "spring passes" and then measuring to find how far to go. No messy calculations. I have gotten the feel of some of my boring bars. I can get real close in a few passes. Sometimes rather than do some spring passes I'll back off the cutter, advance until it just touches then dial in the finish cut. Scott G. Henion Craftsman 12x36 lathe: http://shdesigns.org/Craftsman12x36 ------- Re: new article: Boring Bar Thoughts Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Tue Jun 4, 2013 4:02 pm ((PDT)) Scott, It does seem that a lot of people make extra passes until all of the spring is gone from the boring bar. It works but can be a lot of extra time if you are boring a deep hole. One thing that has bitten me is when I need to take off just a few thou after making, say a 20 thou cut. The "spring pass" easily cuts deeper than what I wanted and I go past my goal. I'm all for avoiding "messy calculations" which is why I put them all into a program. You just input your measurements and the program tells you the next dial setting. The minimum number of passes are required. Rick ------- Re: new article: Boring Bar Thoughts Posted by: "Doc" n8as1x~xxaol.com docn8as Date: Tue Jun 4, 2013 6:20 pm ((PDT)) > The "spring pass" easily cuts deeper than what I wanted and I go > past my goal. AMEN !!!! i was a slo learner, been there too many times...... but now if i am anywhere NEAR MY FINAL SIZE, I BACK OFF THE CUT & REMOVE THE SPRING, taking a fresh cut ...& if the bit is not adequately stoned, there can be the same buildup (doesn't cut, so add some more & when it finally cuts, it is too much d.o.c.). the great surprise was when i got the Reed 14 in, & monarch A 14 in, 1700# & 2000# ...that the spring, although less, was STILL THERE.... best wishes doc ------- Re: new article: Boring Bar Thoughts Posted by: "Rick Sparber" rgsparberx~xxaol.com ate: Wed Jun 5, 2013 9:25 am ((PDT)) Doc, Good to hear from you. All boring bars have spring. Even if you support the bar at both ends, it will still deflect at the cutter. Now, if the bar is 5” in diameter and, say, 2” long, it will be hard to measure the spring. But it will still be there. Rick ------- Re: new article: Boring Bar Thoughts Posted by: "Curt Wuollet" wideopen1x~xxcharter.net Date: Wed Jun 5, 2013 8:07 pm ((PDT)) I heartily second that, I've been working for the past month with a fairly serious Leblond Regal 15x36 and all the same problems are there. just in less amounts. When you you have to make sliding or light press fits for ball bearings and the like, it still takes great care and technique to "hit your fits". Especially with carbide insert tooling that produces horrible surface finishes with light cuts working in steel. Regards cww ------- Re: new article: Boring Bar Thoughts Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Wed Jun 5, 2013 8:20 pm ((PDT)) Cww, Since the uncertainty is due to the boring bar and not the lathe, a more solid lathe should not help. I beta tested the program with a friend and have a minor improvement to make. But he liked the program enough that he plans to buy a TI-83 Plus tonight on eBay. I will load it with the program and then get a lot more beta testing from him. A second guy in Tucson also plans to test out the program. With my friend, on the first try he got within 0.0005” of his goal. Oddly, on the second try it was off by 0.0025” which is horrible. No change in the program so I don’t know what was going on there. Could be a software bug but it more likely something changed in his technique or machine. Rick ------- Re: new article: Boring Bar Thoughts Posted by: "Curt Wuollet" wideopen1x~xxcharter.net Date: Wed Jun 5, 2013 8:52 pm ((PDT)) Perhaps then, the uncertainty is not entirely due to the boring bar. I've found many contributors, spring being perhaps the largest. But everything has to be tight and right to really dial in the process. It does help that the Leblond carriage weighs more than my entire craftsman lathe. But any well reasoned method is helpful and appreciated. Regards cww ------- [atlas_craftsman] new article: Lathe Assitant Program for a TI-83 Plus Pocket Calculat Posted by: "Rick Sparber" rgsparberx~xxaol.com rgsparber Date: Tue Jun 4, 2013 5:22 pm ((PDT)) The related article that presents the program can be found at: http://rick.sparber.org/LAT.pdf Rick ------- Latest project: Boring bar holder [atlas_craftsman] Posted by: ksierensx~xxmsn.com Date: Thu Jan 2, 2014 9:36 am ((PST)) Just finished another project and thought I would share. I made a boring bar holder for my Craftsman 101.21200 (618) lathe, so now I can use 1/2", 5/8" or 3/4" boring bars. I uploaded them to the photos folder, "Kurt's Toys", but here are some links to the pictures also: http://i168.photobucket.com/albums/u169/ksierens/Shop/boringbarholder.png http://i168.photobucket.com/albums/u169/ksierens/Shop/boringbarholder1.png ------- Re: Latest project: Boring bar holder Posted by: "Starlight Tool Services Ltd" starlight_toolsx~xxtelus.net Date: Thu Jan 2, 2014 9:43 am ((PST)) Kurt. Nicely done, well made and very functional. Walter ------- Re: Latest project: Boring bar holder Posted by: wa5cabx~xxcs.com Date: Thu Jan 2, 2014 10:08 am ((PST)) Kurt, Nice job. Should be quite useful. But one minor point you would need to know if you ever need to ask the Group a question about your lathe. Sears 101.21200 does not cross to Atlas 618. It crosses to either Atlas 3950 (Zamak headstock) or Atlas 10100 (cast iron headstock). Atlas 618 crosses to Sears 101.21400. The 3950 and 10100 are also known as the Atlas 6" Mk2. Robert D. ------- Re: Latest project: Boring bar holder Posted by: ksierensx~xxmsn.com Date: Thu Jan 2, 2014 10:48 am ((PST)) Yes, I know it is not the same as the older "618" lathes, mine is a 101.21200 with the cast iron head. Thanks ------- Re: Latest project: Boring bar holder Posted by: zoyagenax~xxyahoo.com gennady_123 Date: Thu Jan 2, 2014 11:25 am ((PST)) Kurt, very nice job. Is there provision for height adjustment or is it made for your particular boring bars? Gennady ------- Re: Latest project: Boring bar holder Posted by: ksierensx~xxmsn.com Date: Thu Jan 2, 2014 11:34 am ((PST)) Gennady, No there is no height adjustment, I just mounted my boring head on the lathes spindle and bored it along the center line, though you can rotate the bar to adjust the height of the tool tip. ------- Re: Latest project: Boring bar holder Posted by: "Richard Hughson" richughsonx~xxgmail.com Date: Thu Jan 2, 2014 4:33 pm ((PST)) Very nice job, sir. Where do you buy a 3/4" boring bar? I'd like to have one myself. Rick H ------- Re: Latest project: Boring bar holder Posted by: ksierensx~xxmsn.com Date: Thu Jan 2, 2014 5:09 pm ((PST)) KBC tools, very reasonable, but they are local for me. ------- Drilling Tailstock "wobble" [TAIGTOOLS] Posted by: edfredfred1x~xxfrontier.com karlh_1 Date: Fri Jun 27, 2014 7:15 pm ((PDT)) There is a noticeable wobble in my tailstock when I attempt to axial drill. The movement comes from the lever activated shaft and can be almost eliminated by tightening the shaft screw; but then I can't advance the chuck to drill the hole. (These are small holes, less than 1/4 inch, so a boring bar is pretty well out of the question.) I measured 14 thou variation about an inch beyond the chuck, but this was down to about .0003 when I tightened down the screw. (No name cheapo dial indicator marked to .001.) I got about the same results with my "Keith Brooks/ Dean Williams" extended dead center, with even less variation if I tightened down the nut and the screw. I could not find any variation measuring the diameter of the shaft of the dead center/ram from Taig. My idea is to put in 2 more screws - in line with the factory screw and along the axis of the spindle - close fit above the gap and threaded below the gap. This would allow me to adjust the gap/hole in the tail stock, not unlike the gib adjustments on the cross slide or saddle. Snug the new outer screws up as much as I can while still allowing the ram to slide, then using the center screw (the factory screw) to lock it down when I need to. Has anyone else tried this, or does anyone have any other ideas? Thanks! ------- Re: Drilling Tailstock "wobble" Posted by: "Gerrit Visser" gerrit-mlx~xxpsgv.ca gerrit308 Date: Fri Jun 27, 2014 8:22 pm ((PDT)) First I would check the horizontal and vertical alignment of the TS to HS. Put a centre in each and line them up. Horizontal you can adjust on the TS. Vertical will need shimming under the HS (if TS is high) or vice versa. I had a vertical offset, and it snapped the tip off a very small centre dirill!!! And holes of course were tapered. Gerrit ------- Re: Drilling Tailstock "wobble" Posted by: "David Robertson" david-machinesx~xxdavidrob.com Date: Fri Jun 27, 2014 8:28 pm ((PDT)) Perhaps not the suggestion you were wanting, but Miro 100 makes boring bars for holes less than .05 inches in diameter. There are probably other manufacturers also. Just Google Micro boring bars. They are not cheap. David ------- Re: Drilling Tailstock "wobble" Posted by: "pe3hmp" pe3hmpx~xxhotmail.com Date: Fri Jun 27, 2014 10:52 pm ((PDT)) https://www.mitsubishicarbide.com/mmc/en/product/pdf/b/b042g.pdf Mark ------- Re: Drilling Tailstock "wobble" Posted by: "Ed Fred" edfredfred1x~xxfrontier.com karlh_1 Date: Sat Jun 28, 2014 9:42 am ((PDT)) I am glad for the information and for Marks link, but I am more interested in a bacon cheeseburger solution, not a filet mignon solution. I'm afraid the micro boring bars will have to go on my (way too big) wish list. kh ------- Re: Drilling Tailstock "wobble" Posted by: "Will Schmit" anchornmx~xxyahoo.com Date: Sat Jun 28, 2014 10:25 am ((PDT)) Ed, I use carbide end mills as boring bars. I typically buy 1/8" shank carbide tooling from Bits and Bits, ranging down to .005" tapered end mills. The flat ended 1/8" bits can be indexed to have one flute facing the user -- I use a CNC table to navigate the hole to be bored. I suppose it could be done with any size flat end bit -- this is just an example. ------- Re: Drilling Tailstock "wobble" Posted by: "Larry" yrralguthriex~xxgmail.com Date: Sat Jun 28, 2014 2:57 pm ((PDT)) Bacon-Cheeseburger solution: If you cannot tighten the tail stock clamp enough so that the center will just slide with less than visible movement something is wrong with the clamp. I would take it apart and make sure that it is clean, put back together, tighten until it is resistant to movement and then if the play is still there I would contact Taigtools. Adding screws for more clamping area won't work since you still don't know where center is. They should fix it for free. My opinion ljg ------- Re: Drilling Tailstock "wobble" Posted by: "Don Rogers" Donx~xxCampbell-Gemstones.com campgems Date: Sat Jun 28, 2014 7:57 pm ((PDT)) I have a tailstock that I screwed up using it as a steady rest when turning a length of ½ x10 acme thread rod. You learn a lot from your mistakes. I have since replaced the tail stock, but here was my plan for savaging my old one. I was going to use the same method I use to make boring bar tool post. I make a blank post and mount it on the cross slide, then with a drill mounted in the spindle, drill and then ream to fit the bar. This gives you a dead on center height to the spindle. My plan was this. Find a suitable thickness of aluminum to take up the gap in the lock groove in the tail stock. Lock it tight and then using a boring bar in the head stock and the tail stock ahead of the cross slide and adjusted to just move on the ways, re-bore the tailstock to a size you can press fit a bronze bushing in. Then re-bore the bushing to the ½" size of the Taig ram. Add a couple pointed set screws in the tail stock to bushing just deep enough to prevent the bushing from turning, then use a hack saw to cut through the slit in the tail stock to split the bushing. You now have a bronze to steel bearing surface that you can lock or loosen for lateral movement as needed. The aluminum to steel mate was not a great idea, especially if you did something stupid like I did. This should give you a good slip fit for drilling, but a dead on fit for between centers work. Don ------- Re: Drilling Tailstock "wobble" Posted by: "Paul J. Ste. Marie" taigx~xxste-marie.org Date: Sun Jun 29, 2014 12:02 am ((PDT)) On 6/28/2014, 'Don Rogers' Donx~xxCampbell-Gemstones.com wrote: > then use a hack saw to cut through the slit in the > tail stock to split the bushing. Hmm, after going to all of that trouble I'd make a split-dowel clamp instead of hacking up all that precision work.\\ ------- Using a boring tool [TAIGTOOLS] Posted by: yougotme2x~xxhotmail.com yougotme2_00 Date: Mon Jun 29, 2015 9:42 am ((PDT)) Group: I need to bore a 1.5" hole in 3/8 mild steel. I have a boring device for doing this but don't know how to use it. I have a 7/8" hole that needs to increase to 1.5". Do I bore a 1" hole and increase it by say 1/8 until I get to 1.5" or do it all at one time? Any thoughts will be appreciated. Thanks in advance. Dan ------- Re: Using a boring tool Posted by: "Rupert" rwenig2x~xxxplornet.com rwenig2 Date: Mon Jun 29, 2015 11:16 am ((PDT)) Dan, If your lathe will handle a larger bit, the fastest way is to drill to about 1.375 and then bore to size using the boring bar. Or, simply bore from the 7/8" hole. Either way will work but finish with the boring bar to get an accurate hole. Rupert ------- Re: Using a boring tool Posted by: "chuck" chuckelsx~xxverizon.net chuckels431 Date: Mon Jun 29, 2015 1:44 pm ((PDT)) Dan, we need to know what machine you are using? is it a mill or lathe? What size and power? Normally if using a Bridgeport type mill I drill the largest hole possible than use a boring head to cut maybe .020-.040 at a time to final size. Pretty much the same on a lathe with the largest boring bar that will fit for the greatest stiffness. I'm no expert but it works for me. Chuck ------- Re: Using a boring tool Posted by: yougotme2x~xxhotmail.com yougotme2_00 Date: Mon Jun 29, 2015 3:47 pm ((PDT)) Chuck, I have a mill/drill 2 hp. and a taig lathe. The boring bar is for the mill. 7/8 drill is the largest I have. I think that boring small increments at a time sounds right rather than going for 1.5" in one pass. Does this sound right? Dan ------- Re: Using a boring tool Posted by: "chuck" chuckelsx~xxverizon.net chuckels431 Date: Mon Jun 29, 2015 5:46 pm ((PDT)) Dan, I seriously doubt you could bore from 7/8 to 1.5" in one shot. Accuracy and finish dictates you use small increments. There are lots of feed and speed charts on the web to help you pick what will give you what you need. Chuck ------- Re: Using a boring tool Posted by: Donx~xxCampbell-Gemstones.com campgems Date: Mon Jun 29, 2015 5:55 pm ((PDT)) Dan: First does your boring devise look like this? http://www.use-enco.com/CGI/INPDFF?PMPAGE=483&PARTPG=INLMK3&PMI TEM=222-1100 If so, you have the right stuff. When you mount the boring bar in the head, use the shortest bar you can. That keeps things a stiff as possible and eliminates chatter. Also make sure there is a positive angle of attack to the bore and you have good heel clearance. Also after adjusting the swing, lock the ways on the head, or you will beat it to death in short time. Also as suggested very light cuts. The sequence would go something like this: With the head retracted fully, mount the bar in the furthest hole that will allow you to cut air. Align the bar to the bore for tool rake and heel clearance. Adjust the offset and take a light clean up cut. Once that is OK, offset more, locking each time and continue enlarging the hole to the point you can move the bar to another mount further from the center, Retract the slide, remount and align the bar and have another go at it. Another approach, and as you have the drill/mill, is to lay out the hole, Center punch the center and set up you mill so the center punch is x0, y0. Then from the center punch scribe a second circle about 3/16' inside the desired bore. Starting at a point on the circle, scratch off 1/4" radius arcs around the circle. Drill each of these ticks with a 1/8" drill. When you make the round of the inner circle, you should be able to knock the center out of the plate. You are left with a ragged hole now, but one you can bore out to size in a few minutes with fewer chips. Just approach the first few boring cuts lightly, The sharp edges of the hole will want to snag the boring bar. The only down side to this method is that your stock has to be centered for boring before the drilling takes place, else you will loose center. Don ------- Re: Using a boring tool Posted by: "Forrest A" atkinonx~xxhotmail.com atkin_on Date: Tue Jun 30, 2015 7:06 am ((PDT)) You need a pretty heafty machine and boring head and or bar to take 1/8" (0.125) cuts in mild steel. ------- Re: Using a boring tool Posted by: yougotme2x~xxhotmail.com yougotme2_00 Date: Tue Jun 30, 2015 5:01 pm ((PDT)) Yes, the boring tool looks like the picture in the link. I think I'll have a go at boring the hole. I might try it first on a wood 2x4. Dan Thanks again for all the help!!!! ------- Re: Using a boring tool Posted by: "Paul J. Ste. Marie" taigx~xxste-marie.org pstemari Date: Tue Jun 30, 2015 6:42 pm ((PDT)) I'd be amazed if you got a boring head to work on a piece of wood. The tool angles on standard boring bars are all wrong. ------- Re: Using a boring tool Posted by: Donx~xxCampbell-Gemstones.com campgems Date: Tue Jun 30, 2015 8:12 pm ((PDT)) Cutting wood or foam is a good idea for testing your setup and feeds. Just remember that the boring bar and head will flex some under load. Very light cuts near the finish line, and repeat the cut at least once before making the next adjustment in size is needed so you are adjusting the cut to the actual finish size, not the deflected boring bar size from an aggressive cut. Don ------- ------------------------------------------------------------------ This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------