REBUILDING a machine implies a complete makeover -- a need to repair or refit or refinish all parts, or most parts. You might think the ideal rebuilding file would cover every part and every procedure. Definitely not. That would be a book, and every book really should have chapters to divide the work into bite-sized chunks/subjects. Consider this file as the introduction in a rebuilding book. It has a few ideas and procedures, but the bulk of the practical tips are in individual chapters (other files on this site). No matter what type or brand of machine you are repairing or rebuilding, there are hundreds of additional useful tips on this site in files like: Atlas Chucks Atlas Parts General Atlas Repair or Fitting Chucks General Cleaning Tips Finish for Tools Lathe Comparisons Milling Machine Comparisons Rust Removal Shaper Comparisons Shaper Repair General and a really big "etc." Sometimes useful tips occur in files talking about modifications to particular brands or types of machine. And unfortunately, tips may be scattered through ANY OF THE FILES HERE if the comment was buried in a message that dealt mainly with a completely different subject. Certainly if you had the time, you would benefit by reading every file on this site, but even then it would be hard to remember what tip was where. If you download the files you need onto your own computer, you can then open several at once with a good text editor or word processor, and then search for key words related to your project. To speed the process, a good program will do the search across multiple open files at once. There are some very good totally free programs that can do this. You may decide to gather YOUR most needed stuff into one or more customized files maintained on your computer. You can take stuff from files here, or from the messages or archives of any group you follow or come across. That file (or files) can become your personal treasury of tips, ideas, sources, etc. from others -- as well as a place to write your own ideas, comments, and experiences. And if you come up with a new wrinkle on an old idea that works better, or a completely new idea or procedure, please share it by posting your experiences to the groups that provided help to you. 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: Sun, 01 Apr 2001 06:04:37 -0400 From: Stan Stocker Subject: OT:LONG JET920, Rebuilding lathes, used lathes, costs in response to WAS:Re: Re: enco lathe Ballendo; I was trying to give a straight honest answer based on my experiences with the Jet BD920N. Perhaps I got an absolute lemon unit that doesn't represent the average unit. If so, then I hope their QC has improved, after all - they crated and sold it that way. The lathe was shipped to me from the JET warehouse, it wasn't purchased at some traveling tool carnival. I don't agree with all of your statements: "The 7x10 and 9x20 import lathes are popular because, although they DO have faults; the faults are well documented, correctable (largely), and CONSISTENT. You cannot say the same thing about going out and getting an old SB. They are all over the map, condition wise... And you had better know what you are getting, or you can EASILY get "just as" burned. Finally, a GOOD SB beats a "stock" 9x20 every way to sunday!" You're right about used gear, a person has to know what to look for, and their limits when it comes to repair. Not only in available tools and knowledge, but also in perseverance and body strength. Some things just have to be picked up. If they weigh too much, you need a helper. OK if you have one, not so OK if you work alone. Not everything can be picked up with an engine crane. You can get the knowledge in many cases with a little work, but sufficient tooling can be rough. If you have to pay a machine shop several hundred dollars to do work you can't handle you need to understand this up front. I've rebuilt auto engines, farm tractors, and some other fun things, so have a bit more experience that applies than some folks. The 9x20 lathes are NOT consistent, I've spoken with folks that had very few problems, and with folks that have had problems worse than mine. The faults I have heartburn with are NOT the fit and finish sort of problems - you can't polish everything and sell it for $895 after all, or with design limitations, everything has limitations. As you have created a group for these lathes I imagine that you have a better idea about the current state of QC at the plants. The faults that bother me are the gross defects in the manufacturing and inspection process. The design limitations are indeed mostly correctable, and have recently become quite well documented from a number of sources. Most of the "fit and finish" class of improvements are indeed fairly simple -- straightforward clean it up shine it up sort of work that is a pleasant way to spend a rainy day. I can't comment on the 7x10 lathes as I've only used one once at a meeting - other than to say that I was quite impressed with the unit I saw, and think that they are quite a lot of lathe for the money! Perhaps they are more consistent than the 9x20 units. Old gear is all over the map. Beaters and perfect condition units in the 9 inch size go from $300 to $3500. Funny thing is there are some great lathes for $500, and some beaters for $2000. At least when a person buys used, they tend to be careful to look very closely or seek advise from someone who can help them avoid getting ripped off. I think the basic reasons the imports are so popular are the same reasons I bought one. A) You can get one. Today or within a week. B) They are affordable. I don't think that folks are buying them because all of their faults are known and documented, although no doubt many folks buy them knowing what they are getting into courtesy of groups such as this one, and that's fine. It's the folks that buy one trusting Jet to provide a good lathe out of the box ( as I did) that get screwed and then angry or so frustrated that they give up and find something else to do. Some get lucky and use the web to get the information. As to a good SB being better than a stock 9x20, that is probably true in most cases, but there are some other considerations. If you like carbide, older SB lathes with sleeve type headstock bearings don't like to run at over around 1000 RPM, with the Workshop series having a max delivered speed of around 700 RPM with a standard spindle. I run the Jet at 1000 and 2000 quite often when using carbide. The Jet and other imports can cut metric or standard threads without much fiddling. Converting an older SB to metric may or may not be easy, depending on the pitch you need to cut. Converting a really old SB to metric may well be impossibly without fabricating some pieces yourself. Older SB lathes will have a lantern type toolpost. You'll likely want to make a four way or mount a QC toolpost. The Jet has a semi QC gearbox, many of the used SB lathes will be manual change gear style lathes. I guess it depends on if the 9x20 is one of the good "stock" units or one of the much work required "stock" units ;-) The basic accuracy of the Jet is excellent if you ignore metric leadscrews with imperial dials. It can cut straight and face square. Doing this well and repeatably with good finish is where the interesting parts begin. You can make a 9x20 into a pretty good lathe, it just may take some doing. To me, the largest problem with these lathes is that they are likely to be a first lathe, and without help from someone who knows the tricks and can tell the difference between machine failure and user failure it can get really frustrating. Without access to another lathe, possibly a mill, and a fair bit of tool rebuilding experience it can be really tough to sort out the problems with these lathes. Remember that in 1995 there was no 9x20 group, and a lot less web support for HSMs. CAMS - the once a month "club" - didn't exist, and our few folks are scattered over PA, MD, DC, and VA. I was the only guy with a lathe I knew. A person with no experience can easily end up with a used lathe that is worse than a new import, no doubt about it. If I hadn't spent years building and rebuilding assorted optical and electromechanical gear and doing a lot of auto repair I wouldn't have known where to start. When I bought this lathe I hadn't had a shop class since 1972, and hadn't touched a metal lathe other than (rarely) some large South Bends and such since high school, and had changed jobs and states so I couldn't get a hand from the guys I knew at the old manufacturing plant. I kept thinking that problems caused by the machine were problems caused by me. It took a lot of digging in books, trying things out, and devising tests and figuring out what to measure and how to measure it to decide when it was me goofing, and when the machine wasn't quite right. I certainly learned a whole lot, both about lathes and how to focus the energy of frustration. I asked myself "What am I doing wrong?" a lot. Sometimes it was me, often it was the lathe. The thing that really ticked me off was that I had no other lathe and no mill at the time, so I paid extra for the Jet name just to avoid these problems. I have other JET gear (from Taiwan), and think that all of the Taiwan Jet stuff I have is a good value for the price. I didn't expect a South Bend, Clausing, or Logan for the price paid. I just didn't expect to find grinding grit and casting sand under the cosmoline, to have to replace half nuts and lead screw, lap gibs, relieve dovetail corners, remove grit from inside assemblies, replace the compound because they didn't mill it before grinding so tools sat .093 high, deburr gears and the entire leadscrew (both the original and the replacement) keyway, polish shafts, polish and reduce the diameter of the spindle to let the headstock bearings be adjustable, have to replace ALL of the soft junk hardware, buy a MT3 reamer to clean up the inside of the headstock spindle, and on and on. With the exception of not having to deal with bed wear problems or repainting, my lathe was on par with a beater in terms of the amount of work needed to get a usable lathe. A grit laden sliding surface with burrs is the same problem, whether due to wear or poor manufacturing is beside the point. You'll notice I didn't mention finish/cosmetic items in the above paragraphs. I expect import handwheels to be a bit rough, the paint to be something other than auto show pretty, and a bit of tweaking up and smoothing to be in order. I just don't expect the head to strip out on a socket head cap screw on first removal, to find tapping swarf in the bottom of blind holes, or grinding grit in the dovetails. I don't consider gross failure to function as advertised or having hardware strip on the first use to be a "project", I consider it defective merchandise. When the leadscrew strips off the crest of the half nut threads the first time the nuts are closed, because they didn't deburr the keyway, it is a defect, not something that wants improvement. Making the knobs smoother, the graduations more legible, the fit nicer, the gears a bit quieter are all improvements to fit and finish. Having to use sockets and a vise to press apart the change gears from the shafts that they are supposed to slide on and off of are defects. Making them do it silky smooth is an improvement. Keyways in gears that are crooked are just lousy workmanship. Heck, I broach keyways that end up in the right place in a home shop. It's rather difficult to mess it up if you use the right tools. You expect a company like Jet to use factories that can at least match a home shop guy's basic tool skills. Jet was very good about warranty parts, and had most things in stock. The problem was that so many parts needed replacement. Getting the Taig for small projects actually opened my eyes to how many of the problems with the 9x20 were tool and not user deficiencies. The Taig is so good out of the box. Now I could compare the same tool cutting the same material at the same speed on the two lathes. Something a bit more concrete! Room for improvement is fine, a machine that is unusable out of the crate other than cleaning off the cosmoline and tweaking normal user adjustments is not! My Grizzly mill was cutting metal the same day it came into the shop. I've made some minor modifications and improvements, trammed the head, and added power feed, BUT - it worked as delivered. My Jet drill press poked holes just fine right out of the box. The Taig was a delight the first time I used it, a few minor improvement simply make it better. I looked for a good used lathe for about 6 years before getting the Jet, so I know that many of the old lathes out there are beaters. I spend two days grinding the bed on my 7 foot SB13 using home made fixtures, so I also know a bit about beaters as well as creampuffs. I've said a number of times that making chips today on darn near anything beats the heck out of wishing and waiting and not doing anything. Since you asked: I'll talk about the cost of a beater farther down ;-) The total cost to restore this particular SB9 was about $80: 3 cans Aircraft stripper - $15 4 cans Primer (Rustoleum professional gray primer) - $18 4 cans Color (Rustoleum professional light machine gray) - $20 a bit of spot putty - already had it but if not it would be about $4 Brass polish - $2.50 Perhaps 10 to 15 dollars in shop "stuff" - 10 sheets or so of assorted grit sandpaper, two stripping pads, some quantity less than 9 of scotch- brite pads, newspaper and tape for masking, single edged razor blades, odds and ends (e.g. hard wool felt for oil wicks) as expected for any tear down, repaint, and restore. 2 gallon cans of mineral spirits - $3 A new drive belt - $8 at the local auto parts store, I'm using a serpentine fan belt rather than a leather belt, this has worked well on other tools. If I have to buy leather and glue or lace up a "genuine" flat belt, that's fine, it remains to be seen. Dollars still to be spent: A good live center and tailstock drill chuck on a MT2 arbor. Yes, I can use the ones I have for the Jet, but I like each tool to be complete as far as basic tooling goes. The lathe was purchased for $500, including a lot of tooling, including steady rest, follower rest, three and four jaw chucks, face plate, dog plate, several dogs, about a dozen toolholders, complete change gear set, motor, jackshaft, a somewhat worn Skoda live center, several dial indicators (Starrett and old Brown and Sharpe) on various holders, and other random stuff. The owner built bench with drawers was included - hot riveted construction, a conversation piece at the least. It was cosmetically ugly. It is mechanically excellent in almost all ways, the only exception being the bit of scoring on the spindle, which could not be detected until the teardown. I could likely have ignored it, the spindle felt fine as it was, but cleaning it up is all part of doing the job right. TIME: About 40 hours actual work, including two hours work on the spindle and front bearing as there was a bit of swarf that had crept in and scored things a bit. Part of this time was making a lap for the headstock bore. I've spent more time that this sorting out faults on the Jet 920. The experience gained on the Jet really didn't map to this job, as SB made the parts right the first time, and the previous owner had treated the lathe well. With fresh oil added, this lathe could have been used as it was. I made one new headstock clamp plate, one of the originals had a crack. The original cracked one worked, but what's an extra half hour at the mill compared to knowing there is something waiting to fail left unfixed? About an hour went into making a 12-28 tap to clean out some holes I let some paint wick into, and making a tool to remove the handwheel hardware. I could have bought the tap mail order, but making one only took about 15 minutes as it only had to chase threads, not cut new ones, so a single flute made with a triangular file was adequate for the intended use. If a real tap was available locally I would have bought one, I just didn't want to stop the project for a week waiting on delivery. This lathe was in a guys basement from the time it came out of the crate in the late 30's (1939 I believe), and still has original scraping and frosting visible on most surfaces. Some quick sanity checks on the surface plate showed no problems, so for once a rebuild was actually just a restoration. No scraping needed. I didn't need to ask for any help from others other than my neighbors time to help unload the lathe from my truck as he had my engine crane tied up in his shop. POSSIBLE DOWNSIDE ISSUES of rebuilding used lathes. You can get in to a project that isn't worth doing. If the 13 inch lathe below was a 9 incher, the salvageable parts would have been sold and the bed scrapped. A new 9x20 import does beat a severely ragged SB9! Watch out for oddball lathes! Old SB 13 and 15 inch lathes have a non standard spindle taper, and may have odd leadscrew pitches, such as 6 TPI. Some of the 13 inchers have a 1 7/8-8 spindle nose, so you're going to machine any faceplates and backing plates from raw castings if you can't find them on the used market. If you can handle this weirdness fine. If not, move on to another lathe. Big lathes have BIG HEAVY parts. Don't buy one that needs a tear down unless you can deal with this. There are things that a normal human just can't lift. Don't hurt yourself, use an engine crane, a trolley crane, a boom on a three point hitch should you have a tractor, sufficient helpers, whatever. My neighbor is refurbishing a 15 inch South Bend from the 20's. There are castings in the overhead drive that he and I can't lift together. UPSIDE STORY - The above mentioned 15 inch lathe is in mechanically excellent condition. It is a lot of heavy work, but for the $300 purchase price plus about $400 for a second chuck and repainting materials he will have a 15 inch swing 6 foot bed lathe. It isn't quick change, but all of the gears are there. Pretty sweet if you need a lathe of that size! His job will involve about 50 hours work total. STORY OF A BEATER REBUILD: I have done a true beater SB13 with a 7 foot bed. It was rusted solid, the power feed worm teeth were at least 1/5 gone to rust where the wheel in the apron was pressed down into cow bedding in the bottom of a partially collapsed barn. We skidded it out with a front end loader. What was I ever thinking?!?!?! The ways were so worn that the saddle would rock at the headstock end. It took two days just to grind the bed using a die grinder, home brew fixtures and gages, and a lot of testing and tweaking. No local shop could (or would) plane a 7 foot bed. Trucking the bed back to SB was out of the question, shipping both ways and the cost of planing the bed for a lathe with many other problems was not on the list of options. Parts had to be made. Several cast iron tooth inserts were made and silver soldered into milled slots to replace missing teeth on the back gear. The carriage had to be electrolytically derusted to get it apart. The spindle bearing surfaces were a mess, so I rigged up a makeshift toolpost grinder and redid them. Testing with Plastigage confirmed the job was in spec. It isn't what I'd call 100 percent done yet, although it is under power and doing good work when a lathe of this size is needed. Looks nice with a good paint job on it. A job like this can easily turn into hundreds of dollars more than expected (thousands if you buy replacement parts, I was quoted $350 for just the worm, so I built it up with braze and recut the teeth). You need to be able to hump 100 pound castings around, work on them, and not screw up. You need a mill that can handle large hundred pound parts. The bed alone weighs about 500 pounds, just painting it is a real upper body workout to move it around and roll it over to get to each side. The legs are about 80 pounds each. This one was a real nightmare job that I nearly gave up on several times. I'll guess that at least 200 hours have gone into this lathe, with about 30 hours to go, mostly in gearmaking and making some new leadscrews. More than once it almost became a wood lathe! Before someone jumps in and says that most or all of these parts are available from industrial suppliers, I should mention this lathe was built in 1929. No, you can't get a matching worm wheel and bore it out to press fit or silver braze onto the original hub. I've done this on other machines. I have most, perhaps all, of the US gear manufacturers catalogs. You can't get a 44 tooth worm wheel in this pitch. 45 yes, 44 no. I'll likely make a hob to match the worm and make a whole new power feed worm/clutch part. South Bend has no parts or info available. You can get 5/8-10 LH acme leadscrew though, so there is a source for the threaded portion of the cross slide lead screw! I could have shaved 30 hours work off the job by cutting the bed down, but a 7 footer is pretty rare so it was worth the work. It is at the point that the bed is within 1.5 thou total up/down variation over the entire length, in/out to centerline variation is maybe 2 tenths - hard to measure this accurately on a lathe with bronze rather than roller bearings, and spindle runout is < 1 tenth. No sudden variations, just a nice smooth needle on the indicator. I'll chase a thou when needed without hesitation, chasing a tenth can become irksome. The 1.5 thou variation up/down ends up not meaning much of anything, it you do the trig for any work larger than around a half inch, you find the change in diameter from this source is down in the noise. For a one inch diameter workpiece, you find that the cutter moving down 1.5 thou translates to a finished diameter of 1.000005 rather than 1.000000. A twentieth of a tenth isn't on the list of things I'm going to loose sleep over. Variation that moves the carriage in or out is critical though, as any error translates to double the error in the diameter, and is a constant error independent of workpiece diameter. Cost to rebuild? Don't know. At least $600 so far, and I still have to make a backing plate (1 7/8-8 spindle - you can't buy these new although this thread does show up if you put out feelers to folks that won't shaft you when it appears) and fit a nice 10 or 12 inch 4 jaw. I already had most of the large tools - engine crane, > 1 inch wrenches, large sockets, 20 ton press, and still dropped a fast $100 at Sears for some sizes I needed. Ever noticed the cost of big wrenches? Was it worth it? To me, yes. Although I underestimated the effort required on this one a bit, I learned a lot and got to try out some new techniques. I have a 1200 lb lathe with 54 inches between centers and a 13 1/4 inch swing. The lathe cost $100 to buy. For a total cost of around $1000 including a new 4 jaw chuck, I have a large lathe that can cut 2 to 112 TPI including some of the oddball 1/2 thread pitches, and has power cross feed. I have a nice Rohm 6 incher with removable/reversible jaws I lucked into for $70 that will end up mated to this lathe, right now the original Cushman 3 jaw is on the lathe with freshly ground jaws. I need to make or find a threading dial, like most things on this lathe, it is an oddball as the lead screw is 6 TPI. Would it be worth it to you? Can't say! About half of the time on this lathe was interesting mechanical and machining work, the other half was nasty, dirty, and occasionally heavy labor that I didn't enjoy much after the first 40 hours or so. Getting something rusty but cool apart the first time is kind of neat, looking over a pile of rusty things still to get through can be demoralizing. By the time you're done, you really don't want to see something else old and rusty for a while. Hopefully this will give folks considering new import and old iron some things to watch out for, thing to look for in a good way, and a sense of just what they are getting into. If buying new import, I would still buy a 13 inch import lathe before I bought a 9 inch one, they seem to have some grasp of QC for these larger lathes, and the included tooling and chucks are a better grade. I'll have to get on the 9x20 list, no doubt there are some things I can learn, and perhaps share. Stan ------- Date: Wed, 11 Apr 2001 22:45:27 -0700 From: "gbowne" Subject: Re: Re: Spindle dead center problem [HEADSTOCK SPINDLE WITH STUCK ADAPTER IN THE MORSE TAPER] This is pretty close to the way I remove stuck, stubborn, frozen collets, taper drills, etc. from spindles. Pretty good sound info. Thanks, Gregory Bowne >>Snippit<< Regarding Robert McDonald's Morse Taper sleeve problem, there is a way it can probably be extracted without destroying it and without banging on it, thereby avoiding potential damage to the bearings and spindle. Firstly a few presumptions, if these figures do not match your situation adjust accordingly. Through bore of spindle 13/16", through bore of sleeve 1/2". Make a nose cap without threads, close fit over threads, internal shoulder such that it is supported by the face of the spindle but will allow the sleeve to pass through for at least 1/4", closed face except drill through 1/2". As MT3 has a nose diameter of 0.938" a likely bore for the shoulder is 0.950" or 0.975". Make an extraction tool, max OD 0.800" (if 25/'32 spindle bore try 0.770"). The point is it should be a close fit in the through bore to keep it centered and in axial alignment. On the forward end this will be turned down to barely pass through the bore of the sleeve, Maybe 0.490". The small diameter will have to pass through the sleeve from the tail end and extend in front of the spindle by the thickness of the nose cap plus enough to run on a washer and nut. Presuming your estimate of 2 1/2" for the sleeve length is correct and the nose cap extends in front of the spindle 1/2" the 1/2" extension should be 2.50" + 0.50" + 0.75", total 3.75". The 0.800 section should be long enough to not let the extension tip down before it passes through the sleeve, lets say at least 2", longer is better. Buy a 1/2" nut and washer, then thread the extension of the extraction tool to match the nut and long enough that the entire section of the tool extending in front of the nose cap is threaded (3/4" ?). If any of the above doesn't match your situation, adjust accordingly. Slip the extraction tool in from the tail of the spindle and through the sleeve, slide the nose cap over the extension and over the spindle threads, slip on washer, and run nut on. When all free play has been taken up, just start tightening the nut with a wrench, it should pull the sleeve out of the front of the spindle. You will need access to a lathe or to someone who can make these items for you. If you have a 3-jaw or 4-jaw chuck and can use your lathe with that set-up you can use it to do the work. The threading can be done single point or with a die. Hope this is helpful. Anthony Berkeley, Calif. ------- Date: Thu, 12 Apr 2001 11:58:06 -0400 From: "Ebower" Subject: Re: Spindle dead center problem A better way to try to remove a sleeve in tact is to spray inside the spindle bore with WD-40 or simular and then use a brass bar the size of the spindle bore from the back and try to tap it out first. Cutting the sleeve with a hacksaw and then taping it with a punch will destory the sleeve. Most lathes use a reducer in the headstock to allow for use of the same size centers as the tailstock. ------- Date: Thu, 12 Apr 2001 10:59:28 -0500 From: "M K (Skip)Campbell Jr." Subject: Re: Spindle dead center problem If you have not damaged the MT3 to MT2 adapter and if you don't have a lot of MT3 arbor tooling that you want or need to use on the lathe, why not just leave the adapter in and use MT2 tooling? If you really need to remove the adapter, you could make a dog leg punch by bending the end of a 1/2" rod, about the last inch, and grinding the outboard edge to fit the edge of the adapter with a lip inside so the punch will not touch the MT3 surface of the spindle. Soak with penetrating oil. Give a few good taps. If it doesn't budge, soak again overnight and tap again, working around the edge of the adapter. Don't hit it too hard. You could damage the bearings or strip the punch or adapter edge. Soak again over night and try it again. I have had success with this method with badly rusted tube in cast iron where I did not want to hit so hard as to break it. On the 4th day, tapping with the same force as previous days, the tube came loose. I also like the idea of tack welding a disk in the adapter to provide a surface to knock it out but I'd try the offset punch first. Good luck, Skip Campbell Ft. Worth, Texas ------- Date: Fri, 22 Feb 2002 00:43:13 -0500 From: Stan Stocker Subject: Long, both on wind and math WAS:Re: Shimming the head. [LATHE TAILSTOCK NOT CENTRED] To a great extent, the effect of a given amount of vertical offset of the tailstock is determined by the diameter of the work being done. I worked this out pretty carefully several years ago while making a fixture to allow me to regrind a badly worn 7 foot South Bend bed in my shop. The answers I got surprised me, to the point that unless you can rock the saddle or bind it hard over the range of a travel, I usually give the advice NOT to regrind a bed, provided there is not a lateral (horizontal) displacement of the cutter with respect to spindle centerline. A thou in and out of the cutter gives 2 thou variation in diameter. Not a good thing. An offset tailstock front to rear (tailstock set over) will give twice the error in the finish diameter. A vertical offset generates less error than you would expect. It is a non zero error, but things have to be pretty far out of kilter before it ruins your day in most tasks. The original post stated the offset was a few hundredths. That would be quite a bit. Any chance the post should have said thousandths? If it is in fact a few hundredths, I'd suggest the tailstock or headstock are out of spec, or one or both centers are incorrectly ground. If a few thou, and not a matter of the centers being off center, ignore it or cut down the tailstock. It won't take long to do this, I'd think a few minutes at most with some 400 grit oiled down to the bed, and sliding the tailstock back and forth on the abrasive would do the job. I'd also ask the method used to determine the offset, getting a really accurate test of this requires an accurate test bar held between centers. If you hate math, here's the bottom line. If the centerline of a workpiece raises 11 thou over the length of the cut, and the target finish diameter is 1/2 inch, you'll see a half thou of taper over the length of the cut. 11 thou is quite a bit of offset. The larger the diameter of the work, the less a vertical offset contributes to any taper. If you want to see how I got here, the math follows. ASSUMPTIONS: 1) If the cutter drops x below the starting centerline, it has the same effect as the workpiece centerline raising x above the starting centerline. Simply stated, it doesn't matter if the cutter lowers 5 thou over 2 inches of cut (worn bed), or if the work is inclined between centers so that the workpiece centerline raises 5 thou (headstock or tailstock center high). 2) The workpiece is of large enough diameter, and the cutting edge sharp enough, that a few thou above or below centerline does not change the cutting angles sufficiently to result in different cutting behavior of the tool. Obviously if you have the effective cutter height change by 30 thou while cutting a 50 thou diameter this entire explanation is completely invalid, as you would go from cutting to being completely clear of the work! 3) When determining worst case taper for a given amount of cutter to centerline vertical variation, the staring point of the cut is dead on center. This simplifies things a bit, if you think through the results of starting above centerline, and ending below centerline, you will end up cutting a very shallow concave surface over the length, rather than a taper. 3a) The starting diameter is exactly the desired diameter, so that the distance from the nose of the tool to the effective centerline of the work is the adjacent side of a right triangle. 3b) The cutter drop (or rise) is the opposite side of a right triangle. 3c) The actual diameter produced is the hypotenuse of a right triangle. 3d) The juncture of the adjacent side and the hypotenuse is at the effective centerline of the work. Yes, this means I've flipped the right triangle from the conventional representation. It's upside down, and the vertical or opposite side is to the left. 4) The tailstock and headstock centers are perfectly aligned horizontally, i.e. no taper is being created by tailstock set over. 5) Flex in workpiece and tooling is not considered, the work and lathe are perfect, so only changes in effective cutter height effect the resulting diameter of the workpiece. 6) Tool wear is discounted. If you have a tool wearing fast enough to generate significant taper, you have the wrong tool, and no doubt a very poor finish on your cut! Now dust off old Mr. Pythagoras, and give this a thought. If the cutter drops one thou while cutting a one inch diameter piece of work, what is the change in diameter of the work piece? a^2 + b^2 = c^2 Let a = target radius of the work (0.5 inches, or diameter / 2) Let b = cutter vertical drop, in absolute numbers, i.e. always positive as it will always result in an increase in diameter, assuming the cutter setting in a above is dead on center at the starting point of the cut (assumption 3a). Let c = the actual radius of the cut workpiece, or actual diameter / 2. Quick check with no vertical variation in cutter height: a = .5000, b = 0 .5000 ^ 2 + 0.0000 ^ 2 = 0.2500 SQRT (0.2500) = 0.5000, therefore diameter (c) is 1.000 inch. No surprises so far. Now, lets introduce 1 thou drop: Again, a = 0.5000, b = 0.001 0.5000^2 + 0.0010^2 = c^2 0.2500 + 0.000001 = 0.250001 SQRT(0.250001) * 2 = 1.000002 diameter or if you prefer, two millionths of an inch over target. Now do it for 1/4 inch diameter: 0.1250 ^ 2 + 0.0010 ^ 2 = c^2 0.015625 + 0.000001 = 0.0156256 SQRT ( 0.015626) = 0.125004, ( times 2 for diameter) giving a diameter of 0.250008. With this rather windy set up, lets figure out how much the cutter has to drop to generate a half thou error for a 1/2 inch target D. c = 1/2 Actual D(0.5005), or 0.25025 a = 1/2 Expected D (0.5000) or 0.2500 c^2 - a^2 = b^2 0.25025 ^ 2 - 0.2500 ^ 2 = b^2 0.062625 - 0.0625 = b^2 0.000125 = b^2 0.011183 = b, or simply, the change in effective cutter height has to be about 11 thou to generate a half thou error in a target diameter of 0.500. Repeating the exercise for a one inch diameter show that the cutter height must change by just over 15.8 thou to generate a taper of half a thou. Cheers, Stan ------- Date: Thu, 21 Feb 2002 22:50:02 -0800 [taigtools] From: "Nicholas Carter and Felice Luftschein" Subject: Re: Re: Shimming the head. If the tailstock is offset to the side (offset horizontally) then it will cut a taper directly in proportion to the offset. This means that is you have a 6" long piece, and the tailstock is offset horizontally by .010 then it will cut a taper that is .010 less in diameter at one end than the other. If the tailstock is offset vertically then it will not have a corresponding taper, rather it is a pythagorean function of the diameter of the work vs the offset. If you do a graphical analysis of this you will see it has much less of an effect than horizontal offset. I should make some drawings up showing this. In other words, if in the same example, the tailstock is offset .010" higher at one end of a 6" piece (in other words the tip of the tool is .010 lower at one end than the other), that is, for examples sake, 1/2" diameter, then it will cut The square root of (.5" squared plus .010 squared), or .5000999" [WRONG -- SEE NEXT MESSAGE] See our web pages http://www.cartertools.com/nfhome.html ------- Date: Thu, 21 Feb 2002 22:55:07 -0800 From: "Nicholas Carter and Felice Luftschein" Subject: Re: Re: Shimming the head. Why do I do math at 10:52 at night? It is a function of the radius of the workpiece, not the diameter, then doubled to find the diameter. it should be 2 times (square root (.25" squared + .010 squared)) .50039984" larger diameter See our web pages http://www.cartertools.com/nfhome.html ------- Date: Sat, 23 Feb 2002 02:32:01 -0500 From: Stan Stocker Subject: Re: Long, both on wind and math WAS:Re: Shimming the head. Hi Dan; You are right, it isn't intuitive. It took me a while to figure it out and satisfy myself that I wasn't overlooking something really silly. We are so used to tail stock setover generating a constant rate of taper that it feels weird. The REALLY weird one is that if the cutter starts above centerline and ends below centerline (or vice versa), you get a concave surface on your cylinder, thinnest at the point where the cutter crosses the centerline. That took a few minutes to realize. Now I'm just trying to figure out some really cool application for such trivia :-) I had a very strong driving force making me think about this situation, but from the view of the cutter height varying as a result of a less than perfect bed rather than from a high or low tailstock. An old SB13 with a seven foot bed came my way, in very bad shape. There was severe wear ( 18 thou or better) over about 4 inches of the carriage ways by the headstock. I had to decide if the bed could be salvaged without shipping it out to be planed and ground. If not, I would have cut it down and ended up with a shorter bed 13 inch lathe, or converted it to a very heavy wood lathe, as it was such a beater that there was no way I would spend the money on shipping the bed to a shop. I couldn't find a local shop that could plane a 7 footer. The question became quickly one of how good does it really have to be, and if there was a fair chance that I could meet the requirements. The carriage would rock and bang near the headstock when your grabbed its ears, so ignoring the wear just wasn't an option. Because SB uses 3 vees, flipping the bed end for end was out also, although I sure tried to figure a way. Using a die grinder with a cup stone on some shop cobbled fixtures, I reground the carriage vees to spark out over all but an inch or so at the headstock end. Leaving a section of the original and unworn ways gave a reference surface to set grinding wheel angles with. 2 days later, I had the bed ways ground to the point that less than 1.5 thou variation vertically, and less than 2 tenths horizontally, was indicated. I ground ONLY the ways for the carriage. A few passed with Roloc disks to smooth the slightly rough surface from the grinding, and a few passes across the tops of the carriage vees to cut them down to something near the normal flat top profile finished the way reconditioning. The carriage needed some mill work to allow for the drop in its altitude, but nothing major. Naturally the gearbox and leadscrew had to be shimmed down by about 19 thou to get things back in line, a few gears needed teeth made and silver soldered in, some shafts and gears had to be made, but the old beast works. Still a restoration in process, but a working long bed lathe for about $600, most of it in tools and materials, as the lathe was only $100. I'm planning on getting a 4 jaw Bison 12 inch chuck and backing plate when money allows. Since I have a Taig (naturally), and 2 nine inch lathes, the large lathe is used for only big stuff. Nice thing here is that the work diameter is usually large, rarely a bore less than an inch, and rarely a workpiece less than 4 inches in diameter, so error from a thou or two variation in cutter height gets lost in the noise. I haven't had the need so far to fabricate long shafts with precise diameter over their entire lengths anyway, the biggest thing done so far was a telescope pier. Stan ------- Date: Sat, 15 Mar 2003 01:06:25 -0600 [atlas_craftsman] From: Jon Elson Subject: Re: Re: Slickey Stuff joekott1 wrote: >I believe the stuff you are talking about is called Turcite. I think >this is a brand name so there might be other terms for it. We have >used it to rebuild the ways on some CNC machines where I work. >--- In atlas_craftsmanx~xxyahoogroups.com, tcaudlex~xxv... wrote: >>do any of you guys know what they call the new high tech plastic >material that you can put on the ways of machine tools? I have heard >it mentioned. I want to reduce the friction on the ways of my >Mill/drill prior to installing new zero backlash lead screws. Where >can you get some information on the product? Turcite is a solid material made by Busak & Shamban, their US distributor is Interstate Plastics, at http://www.interstateplastics.com/meta/fmtur.htm I think they also have castable materials. now. But, there is also Moglice, which is cast in-place between the ways and the sliding part. Devitt Machine http://www.moglice.com/ is the distributor of this line of materials. they have about 6 different versions, from water-thin to putty that will stick to the underside of parts. They have a 20 or so page book detailing the applications, techniques, etc. I am going to do a large lathe carriage with Moglice in the next month or so. Jon ------- Date: Wed, 21 May 2003 11:09:30 -1000 (HST) From: Tom Benedict Subject: Re: Check w/Michael Morgan at URL--Re: Scraping On Wed, 21 May 2003, Art Volz wrote: > Michael Morgan is back in business: http://www.machinerepair.com . > See his books, video and tools at above URL. (NB: Michael's URL was > simply found with a Google search.) Michael Morgan is where I got my stuff from. I already had a number of books from Lindsay on scraping before I got the stuff from Michael Morgan. Even so, I'm 100% happy with it. The book didn't necessarily have that much additional information, except in the availability of tools. Most of the Lindsay books assume you're making scrapers from worn-out files. For small jobs, that might well be doable. But I'm very happy I got an honest-to-goodness scraper. It's got a longer handle than any file I've ever used, and seriously relieves the back strain. The video was well done. It contained some information none of the Lindsay books had (probably because when the Lindsay books were written, it was assumed you knew what you were doing when it came to scraping, so a lot was left unsaid.) One of the more important points in the video was pacing. I was under the impression scraping was this turtle-slow process where each cut was a deliberate action. Turns out scraping that way leads to a non-uniform surface. Getting a good rhythm going, but still keeping it slow enough that each stroke is a planned action, works much better. I wound up going about 60-80 strokes a minute. He also shows two ways to do flaking. I tried one of them, and it works quite well. I'd like to learn roll-flaking, but I'd need to get some additional blades for my scraper to grind the smaller radii on them. Bump flaking uses the same blade you use for scraping, so that's the one I tried. All in all I'm a happy customer. Tom ------- Date: Wed, 21 May 2003 14:22:25 -0500 From: "Scott S. Logan" Subject: RE: Check w/Michael Morgan at URL--Re: Scraping Art, and others: While I have no personal experience with Mr. Morgan, there have been MANY people posting to RCM that he is NOT shipping. The web site you reference, still shows a straight edge sold out and "next batch will be cast in mid July of 2002." All the pages I looked at have not been updated since at least last July. PLEASE, if you place an order, at the very least, call him first, and find out if he is actually shipping. Also remember, if you use a credit card, it is against the law for anyone to charge your credit card without shipping, except in very specific, unusual circumstances. And even then, the merchant CERTAINLY should advise you ahead of time that he will charge your card in advance of shipment. Caveat Emptor! Message from Scott Logan Support the anti-Spam amendment sslx~xxlathe.com Join at http://www.cauce.org/ ------------------------------- Date: Thu, 22 May 2003 01:03:21 -0000 From: "mikehenryil" Subject: Check w/Michael Morgan at URL--Re: Scraping The last time I checked there is no phone number listed on his web site. Email seems the only way to contact him and that is a bit iffy, at best. FWIW, everything I ordered from him was eventually received, although the straight edge took around 6-8 months to arrive and there was at least one promise that it had shipped early on in that period. I've heard that he's had a lot of family/financial problems and can certainly sympathise, but I wouldn't send any money that I couldn't afford to lose and definitely not for anything that was needed right away. Mike, near Chicago ------------------------------- Date: Fri, 30 Jan 2004 17:33:29 EST From: n8as1x~xxaol.com Subject: Re: shaper restoration question In a message dated 1/30/2004, aragratx~xxnetscape.net writes: > Well, you didn't ask me, but, if you did, I would say that scraping is > the only way that I have found to get bad rust off of machined ways and > such. Sandpaper just loads up. Rust remover - no luck. Penetrating oil > won't penetrate. First used an old file ground square on the end. Then > I found some hunks of carbide that I used. First held them with > Vise-Grips. Now I have made a holder for them. agreed ...unfortunately , have had to do this more than a few times..........but practice first on scrap , maybe using mild steel /brass bar.....then grind teeth off end of file , grind end at 90 deg w/ a slight radius on rt./lt edges to keep from digging in ...hold down w/left hand at front, & push w/ right ,at angle that works best for u ...( when scraping to REMOVE metal, hard pressed to take off more than a tenth /stroke) ....keep ur scraper stoned sharp! best wishes docn8as ------- Date: Wed, 05 Oct 2005 09:45:59 -0500 From: xlch58x~xxswbell.net Subject: Re: Parting out ??? [atlas_craftsman] gto69ra4x~xxaol.com wrote: >> I've posted about this on various groups. It drives me crazy--they're ruining the machine landscape. Guys realize they can make a few (not a lot more, unless you're selling a QC box) more bucks parting out a lathe than selling whole. So they get (usually mint, recent) good lathes and sell them in chunks. The biggest problem is that the folks buying the parts are keeping their worn-out clunkers running. The most critical wear parts of the nice parts donor (bed, saddle, etc) never find a buyer and are scrapped. So both the number of surviving machine tools and their quality is reduced. GTO(John) << There would be no market for the parts if there weren't machines that needed the parts. Why are twenty busted machines preferable to fifteen working ones? The only issues that bother me are that many of the lathes being rebuilt are not worth it and the ones being parted look pretty good, so things may be going the wrong way. The other issue is that the beds aren't worth shipping so get scrapped. Damn shame, since the Atlas beds with their flat parallel ways can be more useful than many othe lathe beds for re purposing. Finally, the one that really annoys me are the timken machines that get parted so someone can upgrade their perfectly serviceable babbit machine, and the babbit headstock get scrapped. There is nothing wrong with a babbit headstock, and given the light use these machines get in home workshops, the babbit machines have a good chance of not only outliving the owners, but outliving the timken replacement. I found a great babbit machine for my 85 year old neighbor. He briefly considered replacing the headtock with a timken model. I told him frankly that he didn't have a chance in hell of wearing out that babbitt headstock in the years he had left, and should start making chips, not a mess of a good machine. Charles ------- Date: Wed, 05 Oct 2005 11:43:07 -0500 From: Bill Aycock Subject: Re: Parting out ??? One big problem that is not mentioned is the problem with shipping. Many parts and sub-assemblies can be sent UPS, but most full lathes can only go freight. Freight is a problem for many of us. When I get a freight shipment, it usually comes to a terminal over 50 miles away (really). I live east (20+) miles from Huntsville, AL. The terminals for Hsv are all on the west side, by about 25-30 miles. All the local terminals (near me) are "dedicated", in that they only handle certain types of freight. Many lines go through here, but none stop. One source of material I needed had the only Alabama terminal served by her only freight line in Mobile, which is 450 miles from me. I have a pretty good 618 to sell. My only options are to sell it for local pick-up(Severely limiting my market), crate and get to a terminal 50 miles away (I'm 78), or Part-out. None of these is a good choice. Bill Aycock W4BSG Woodville, Alabama ------- Date: Sun, 9 Oct 2005 20:55:43 -0400 (EDT) From: Steve Subject: Re: Gap Bed Lathe? [atlas_craftsman] The book "practical ideas for metalworking operations, tooling and maintenance", which appears to be a compilation of useful tips sent in by readers of American Machinist, one machine shop built a headstock out of plate steel welded into a box and drove it off the original headstock. The objective of this excercise was that by moving the headstock down, the worn section of the bed near the headstock was now out of play. ========================================================================= REMEMBER, MUCH MORE STUFF YOU NEED TO KNOW TO REPAIR OR RESTORE OR USE A MACHINE IS LOCATED IN THE OTHER FILES HERE. ========================================================================= Date: Sun, 29 Jan 2006 06:19:51 -0600 From: "Mario L Vitale" Subject: Re: RE: Cold shops [Metal_Shapers group, but this advice applies to all machines.] Charles, I'll let others respond to your question about about "cold shops", but I want to make a recommendation regarding the shaper... the same recommendation I always make when someone says "I'm gonna completely tear it down." My recommendation is, DON'T!... at least not right away. If you are like me, and I suspect many others in this group, you have far more projects than time (even if you're retired). It sounds like getting this shaper running has not been near the top of your "to do" list, meaning your not in any hurry. If this is the case, and you "tear it completely down", here's what is likely to happen. You'll get half of it dismantled, and it will be taking up a valuable portion of real estate in shop (both on the floor and any other horizontal surface). Then you'll see a set of plans for building a simple taper attachment for your Hendy lathe, so you'll start that project. And then your neighbor comes over with a rusty, cross threaded bolt from his exhaust manifold, to see if you had a die to chase the thread, and you decide it would be easier to just turn a new bolt...you've been wanting to use those little pieces of hex stock that were in the bottom of the box that came with the Hendy. Then your lawn mower dies and you decide, "wouldn't it be cool to build my own engine for the lawnmower!?" Of course that's just before SWMBO decides the kitchen needs painting...this weekend! And just think about what happens when you decide to make the quick change tool holders and decide that the shaper would be perfect for that project. Let's see now, the base is now outside under a tarp, there is a box of parts under one of the work benches, you know where the clapper assembly is, because just last week, you knocked it off the shelf trying to get to your indexing head, that was behind it... Well, you get the picture. Seriously, it makes a whole lot more sense to just start soaking things down with a good grade of penetrating oil and regularly try coaxing it back to life ...lightly tapping, gentle application of pry bars, etc. Only dismantle what you can reassemble in the same session ...or at least in a day or two. Once you get things to move you can see what really needs to be done to make it a useable machine for your purposes ...or whether it is even worth doing. And if you decide that it's more than you want to do, it will be easier to find someone who might be interested in taking on a project. That would, hopefully, delay it's ultimate fate ... the blast furnace. Best of luck, Mario ------- Date: Wed, 9 Jan 2008 15:59:24 -0500 From: John Ruth Subject: FW: [OldTools] Cold chisels GG's: First, John L. Odom wrote: >>> I have done a lot of things with chisels and files >> that would be impossible without machine work today. Then, that Old Millrat Jim wrote: > I still have my apprentice made "other" chisels and punches. I run > across a cape chisel or a diamond now and then, and I think that the > rest of the world does not know what they are. To both of which, at the risk of "me too-ism", I want to say AMEN!!! Especially to Jim's comment, because cold chisels frequently go unsold at the Flea Market, and rarely command a price higher than $1. One correspondent on another list described the cold chisel as "The poor man's metal shaper". (A reference to the machine tool called a Metal Shaper.) Old timers could make a keyway in a shaft with a cape chisel and a 6" rule with two gauge attachments similar to the ones used to lay out stairs with a steel square. They could make a round drilled hole square with a diamond point cold chisel. Just about anything might be undertaken by chipping. The whole story is too long to relate here, but my father his friend once used a cold chisel to make the center hole and the "bolt circle" of a steel automobile wheel larger so they could get home without an expensive tow. It was a fine job - the hole was remarkably true. Dad showed me how to split a nut with a cold chisel when I was a teen. Man, I can't even count how many times that trick has come in handy. In my flea market travels, I buy any old cold chisel I can find if it is one I don't have or it is an "upgrade" for one which I do. What is a "complete set" ? They come in sizes from about 1/4" to over an inch, and in MANY shapes. I doubt I will ever have a "complete set" because I can't say that I've seen every type! [Sigh! Yet another slippery slope!] There's a roundnose type that is rare and underappreciated. The nose is a cone cut off at an angle so that the face of the bezel looks like an elipse. There are also ones that look kinda like a cape chisel, but the flat part is off to the left or the right of the shank. I cannot figure out what these were for, beyond the fact that they work right up against an obstruction. Any galoot without a few cold chisels handy is not completely equipped! Don't know what shapes are still made besides straight and cape, but there's still New Old Stock to be found at your local industrial supply house. John Ruth ------- Date: Wed, 9 Jan 2008 16:48:34 -0800 From: James Thompson Subject: Re: [OldTools] Cold chisels > On 1/9/08, MillRat James wrote: >> I still have my apprentice made "other" chisels and punches. I run >> across a cape chisel or a diamond now and then, and I think that the >> rest of the world does not know what they are. On Jan 9, 2008, at 12:15 PM, curt seeliger wrote: > Sure we do. They're cape chisels, duh. Never heard of them before, > and google makes them look like dull diamond shaped chisels so I don't > know what they're used for either, and I doubt I could recognize one > in the wild. But we sure know what they are. > So, do we need them for turning old sawblades into useful scrapers and > blades and such? cur See John Ruth's post for even more of the uses of cold chisels. Repairing machinery when it could not be removed for service often entailed using a variety of hand tools including cold chisels and punches. Just get it fixed so the factory could get going again. One of the main uses for cape chisels was cutting oil grooves into new bearing surfaces. First the bearings had to be scraped with those funny looking tools with the curved end that are often described on the Bay as wood carving tools. (I still have mine.) There is an art to sharpening those scrapers. Once the shaft would fit the bearing correctly, oil grooves were cut in the bearing to allow the shaft to float on a film of oil. Shafts must not actually come into metal to metal contact with the bearing or the bearing will be destroyed. Cutting oil grooves is an art that must be learned. Just any old groove will not work. Large gears were often supplied rough cast, and Millwrights had to match the teeth for proper contact. Most folks do not know that 3 teeth in each gear must always be in contact with each other. One tooth contact is a certain disaster because one tooth cannot carry the load alone. Fitting a 12 foot diameter bull gear for proper contact with its pinion is a real chore, and it was done with Prussian blue, chisels, scrapers, and files. I worked on one such gear setup for the new BOSP furnace at Kaiser Steel in 1958. The gears rotated the furnace so it could pour off the molten steel. My first experience with a big gear. Like John Ruth, l like cold chisels too, and I always look in the rust pile to see if there is one I don't have. I rarely use one any more, but I still like them :>) Jim Thompson, the old millrat in Riverside, CA. -------