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 more than 70 additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/ SAFETY WARNING BEWARE: DO NOT ASSUME that any subject matter or procedure or process is safe or correct or appropriate just because it was mentioned in a news/user group or was included in these files or on this site or on any other web site or was published in a magazine or book or video. Working with metals and machinery and chemicals and electrical equipment is inherently dangerous. Wear safety devices and clothing as appropriate. Remove watches, rings, and jewellery -- and secure or remove loose clothing -- before operating any machine. Read, understand and follow the latest operating procedures and safety instructions provided by the manufacturer of your machine or tool or product. If you do not have those most recent official instructions, acquire a copy through the manufacturer before operating or using their product. Where the company no longer exists, use the appropriate news or user group to locate an official copy. Be careful -- original instructions may not meet current safety standards. Updated safety information and operating instructions may also be available through a local club, a local professional in the trade, a local business, or an appropriate government agency. In every case, use your common sense before beginning or taking the next step; and do not proceed if you have any questions or doubts about any procedure, or the safety of any procedure. Follow all laws and codes, and employ certified or licenced professionals as required by those laws or codes. Hazardous tasks beyond your competence or expertise should also be contracted to professionals. Let's be really careful out there. (c) Copyright 2003 - 2008 Machining and Metalworking at Home The form of the collected work in this text file (including editing, additions, and notes) is copyrighted and this file is not to be reproduced by any means, including electronic, without written permission except for strictly personal use. ========================================================================= 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