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Lathe - Cross-Slide

 
 

 

 
 
T-slotted Cross Slide (Feb 16, 2001) T-slot cross slide? (Dec 27, 2002)
10K cross slide assy. (Apr 14, 2001) 9" Cross Slide Slop Diagnosis Help (Mar 28, 2003)
Cross Slide Repair (May 5, 2001) New Cross-Slide Threaded Rod (Apr 22, 2003)
Screw size for Top Slide (Oct 3, 2001) Play in SBL9B cross slide (May 23, 2003)
Crosslide sleeve (Nov 17, 2001) Set screw above dove tail in crosslide (Jun 20, 2003)
Worn cross slide on saddle of Heavy 10 (Dec 2, 2001) Rocking crosslides (Jun 27, 2003)
Cross slide nut? (Jan 8, 2002) Difference between crosslide feed screws (Jul 3, 2003)
Refurbishing a worn cross slide (Jan 25, 2002) Tee slot cross slide table (Jul 5, 2003)
Cross slide nut (Jan 22, 2002) Mounting holes in cross slide (Sep 13, 2003)
Heavy 10 Cross Slide Thread Pitch (Jan 28, 2002) Crosslide nut and screw 1/2 -10 LH acme (Nov 4, 2003)
Replacing  Cross/Top Slide Handle Nuts (Jan 30, 2002) Crosslide wanders (Jan 23, 2004)
Hole In Cross Slide (Jan 31, 2002) My heavy 10 cross slide? (Apr 5, 2004)
Unknown hole on SB9 cross slide (Apr 28, 2002) What are these holes for? (cross-slide) (Jun 5, 2004)
T-slot crosslides (Jun 16, 2002) Finished T-slot cross slide (Jun 8, 2004)
Light 10 crosslide screw (Jul 1, 2002) MLA cross slide and faceplate (Dec 21, 2004)
Heavy 10 cross slide (Aug 3, 2002) Crosslide screw/nut repair (Dec 24, 2004)
Ball handle threads on cross slide (Oct 4, 2002) Slotted crosslide or production saddle? (Jan 27, 2005)
SB 9 Cross Slide 7/16 X 10 Acme Nut Misery (Nov 6, 2002) 16" SB cross slide screw (Mar 8, 2005)
 
T-slotted Cross Slide
Has any of you have purchased a t-slotted cross slide from Metal Lathe Accessories? The place has a lot of kits that have been cast by them and just need finished up by the buyer. Does anyone know of the quality, and just how much finishing is required? I've really been considering this, as I feel this would be a nice addition to the South Bend 9". Frank (217)
I've been considering one also. My problem is that I have no mill, so I'd have to get one machined somehow. It would be a great accessory, though, for those of use who have no milling machine. I've been thinking about making just a cross slide plate with a bunch of taped holes, and If I made it out of aluminum, I could probably make it on my own. More of a boring jig, since it would probably not be set up to slide freely on the dovetails. Just adjust it and clamp it down. Paul R. (218)
I am in the process of machining a couple of the kits from metal lathe accessories. so far I am very happy with the kits and supplied reference materials. the guy's name is Andy Lofquist. he is not online to my knowledge. He seems to be a really stand up guy and very knowledgeable. I am a novice machinist, so I asked him a lot of questions before I ordered. I ordered drawings first, and then the cross slide, a milling base and the transfer block. ups destroyed the package and 'lost' the cross slide so I have not seen it yet. Andy has been very good about getting me a replacement for it. It should be here soon, I'll post to the list how it turned out. There is a guy who machines the cross slides, he is listed in the website and in the literature. he quoted me a price of like $179 for the slide machined and shipped with the new gib and screws. I wanted to machine mine myself. Honestly, its not a bad deal considering that the tooling will cost you nearly $100 alone (dovetail cutter, t-slot and countersink). you really need it to make most of the other things. I am paranoid and want to fit mine to my machine so i plan on making it. Andy seemed to be low on stock after the cabin fever show, but he says that new castings are on their way. he doesn't actually cast them himself, he has a foundry cast the parts for him. In addition to the kits I already got, I want to get the milling base and maybe the faceplate. The two castings I did get were pretty good. actually, they are the only castings and virgin cast iron I have worked with, so I don't have much to compare to. They are clean, they were a lot cleaner than I expected. no foundry dirt or sprues or excess flash. They machine like cast iron, really nice with sharp tools. they seem to be cast of a good cast alloy material. So far, I have only milled the transfer block. i am fortunate to know someone with a Bridgeport with all the right tooling and attachments. I spent 6 hours making it, of which 4 I think was jigging and clamping and changing tools. A dro was an extra bonus. It saved me from counting turns etc and with a bit of prep work, little to no layout. the drawings and instructions that come with the kit are very good. remember they are drawings and are not meant to be to scale. Drawing dimensions are 3 3/8" x 3 3/8" x 8". my finished block was 3 1/2 x 3 5/8 x 8. i left it big so I could refinish it again, and to a regular (1/8" increment) size. the slots were flashed over, so I ended up cleaned them up with an endmilling operation at the end. The 2 sides that are solid are meant to be drilled to suit: I drilled and tapped 3 rows of holes at 1 5/8" centers to match the slot and hole layout on the cross slide. I think it will work out pretty good. the milling base is essentially the front half of the cross slide. The center hole accepts the dovetail'd spud on the compound. I have only surfaced it so far. i intend to use it on the rear of the slide with a future milling attachment or my toolpost. Since it will need the same operations to finish as the slide I am waiting to machine them both. i would recommend the milling base as a fixture to use with the cross slide that way you can mount your compound and/or toolpost to the rear of the slide so you can do thinks like turn left hand threads in forward gear. While the 5/16 stud size is standard, i had some trouble finding decent t-slot nuts and clamps. I ended up going with a name brand kit for everything. in the end it ended up costing a bit more than cheap imports, but they are worth the price. I think that you need to think about the other things you will need to work with the cross slide like t-slot nuts and studs to utilize it well. dennis (219)
I have the T-slotted Cross Slide and have been very satisfied with it. It is a good project but you'll first need the transferor block to machine it. this can be a Catch-22 situation since you also need the T-slotted Cross Slide to machine transfer block. unless of course you have a milling machine available to you. be aware that the T-slotted Cross Slide is prone to band slightly when you tighten down on it. this makes it difficult to move you will have loosened the gibs to use it otherwise it is very useful. my suggestion if you do not have a milling machine available to you is to have it made for you this is what I did.. or if you have plans to buy a milling machine later you might want to wait a put your money there instead. I find milling machine is much more useful to me although I still use the T-slotted Cross Slide occasionally. Rick (221)
Andy Lofquist does have a website, and it's quite good. Check out http://statecollegecentral.com/metallathe/  for all of his stuff. I met him at Cabin Fever this year and he seems like a very nice guy. The consensus on the Usenet metalworking group is that his castings are superb. Sure liked everything I saw. Now all I need is about $1,000! Charles (249)
10K cross slide assy.
My lathe was apparently damaged at some point in time, and repaired by some well meaning individual who either didn't know how or didn't have the resources to do it properly. Perhaps they weren't so well meaning after all. It is a 10K model A without the taper attachment, and according to the parts list there appear to be some missing pieces in the area of the crossfeed bushing. There are supposed to be (2) three-piece thrust bearings, there are only 1 and 1/3. Also absent is the Oilite bearing that should go between the rear thrust bearing and the feed bushing. And it would appear from the parts list that what is known as the C.F. (crossfeed) sleeve is supposed to be pinned to the crossfeed screw itself. Is this correct? How is the sleeve supposed to locate along the axis of the screw? There is no pin, and no hole for it in the screw. Is there supposed to be a way to adjust the play or load on the thrust bearings, or is it fixed by pinning the sleeve to the screw? I speculate that the machine somehow tipped over on its face, or something heavy feel on it, and the outer end of this assembly was damaged. I submit a bent crossfeed ball crank and apron handwheel, and a broken and weld-repaired compound as evidence of this. Whoever attempted to fix the machine did so without buying any new parts, and just did the best they could with what was leftover. I've got it put together so it's "useable", but it's not right. I'm having trouble maintaining repeatability on diameters. (519)
Contact Meridian Machinery www.mermac.com  or call 631-777-1317. He has used parts and a very vast knowledge. The owner Dave Ficken is a very patient man and has helped me with my search for parts. Jim (520)
Here are some instructions that will help with your cross feed bushing and bearing fitting problems. These are actually for the "Heavy Ten" lathe but the process is the same for the nine inch and 10K lathes with large dials (1 3/4"). The Sleeve is supposed to be pinned. The oilite bearing was used on later models. Earlier models didn't have them (they relied on the bushing only). My parts breakdown only lists one oilite (bronze) sleeve bearing and it is to be located at the ball crank end of the bushing. If you need one, you can make one from a standard oil-impregnated bronze bearing, 5/16 ID x 7/16 OD x 1 1/2"Long and reboring the ID out to 3/8". The thrust bearings can be bought from any good bearing supply house. I used INA (a manufacture) Bearing No: FT 010. Webb (521)
Cross Slide Repair
The lathe is back together! Check the project description at http://pages.cthome.net/errol.groff/south_bend_cross_slide_screw_repair.htm  Errol (594)
Errol, I will eventually be making a replacement cross lead screw and nut for my 9". It is very helpful to see another's ideas. Question: What factors may you opt for a commercial rod and nut instead of machining your own? Paul R. (595)
Paul: You ask a good question. What is it that makes us choose to do it ourselves or to have is done. Our usual motto at school is "What do we have more of, time or money?" Most always the answer is time But is this case I really needed to get the machine back in operation so I decided to go this route. Now that I have prototyped it out I will assign one or two of my students to follow up with the parts for the next two most needy lathes. Keep in mind that most of the work on this one was done during school April vacation when I didn't have the responsibility of minding students. It is difficult to do machining when you have to keep an eye on 12 or 13 kids. Without getting way off on a tangent about kids today not a lot of them have the "stick to it" attitude that is necessary to develop a project like this. If a student has to remake a part they will probably throw up their hands and walk away from a task. Pretty much the only "club" an instructor has these days is a grade and way too many kids don't care about their grades. I realize that I am painting with a broad brush and I DO have some students that I can rely on to do their very best on what ever I assign them but there are too many projects and not enough of the good kids to do them in a timely fashion. (596)
Errol Makes a lot of sense. Now if you were going to make one from scratch, what kind of steel would you use, and any particular kind of brass? I'm obviously asking with the intent of making my own replacement parts. There's an article I have in HSM or MW (can't remember which) that addresses some of this, but I don't know if it mentioned type of steel/brass. Paul R. (597)
Paul, I did exactly this project on my 10k. Having had NO experience cutting threads it took me much longer than it would today. But it was a blast!! I used 12L14 for the screw. That went so well I ended up redoing the tail stock screw and the compound too. :) I bought the cross slide nut from Southbend, about 55.00. That looked to be a bit more than I was prepared to take on at the time. My lathe has the power cross slide. I didn't make the "power drive end". (btw South Bend wanted 645.00 to make this part). I did make the threaded portion. The over all length about 1 inches longer than the original. Cut off the old one just shy of the old threads, leaving the stub as long as possible. Bored a hole in one end of the new screw to match the stub length and diameter. Then silver soldered the two together. What a difference!! The tail stock quill threads were a bit worn. I wasn't feeling up to making a new quill yet (no taper attachment) so made a new feed screw that fits the quill threads as they are. Works great. Did the same for the compound screw. Ray (598)
Screw size for Top Slide
My 40's era SBL 9 has 12-28 setscrews for the Gib. I have not found a source for these and was thinking of maybe drilling the holes and retapping 1/4-28. There is not a lot of metal there but it seems like such a small change. The question for those with more recent lathes, is South Bend still using the 12-28 screws or did they go to something else? (1700)
I'd resist the temptation to do that unless necessary. Are they that rare? Tried specialist fastener suppliers? Want me to look?(1701)
I would hate to see you do what you suggest because you can't find 12-28 set screws. Here is a place that has 2200 of them in stock http://www.iinc.com/barber/inventss.html Yasmiin (1702)
You might check with Fastenal http://www.fastenal.com , we have a local store here in Waco, TX and they seem to have a lot of specialty items. Lew (1707)
No, Yasmin sent me a link to a stainless set screw supplier that has lots of sizes. I am a little surprised that the big houses like McMaster-Carr and MSC don't have these sizes - even if they aren't used that much anymore. Bill (1721)
This may have been done to keep them in place. That just adds to the motivation to single point them. Make your blank the same diam as the existing screws, if you have any to measure. The tricky part is cutting the slot, one of those little hacksaws that looks like a cheese cutter helps. I think I made mine with a die but I started with a blank the size of the other screws. This screw is not a fastener, its a translation screw, and can be expected to be odd. RC (1722)
As far as cutting the screw slot, they do make some files for this. I guess you could use a thin hacksaw. Use your finger (thumb) nail as an initial guide. Just let the saw blade or file rub against your finger nail. It won't bite. The files I am talking about have the cutting teeth on the edge only. As I remember they come in two widths. I think .062 and .032 approx. Brownells should sell these. Don't put a lot of pressure on them as they will break. Let the file do its work. Tom (1723)
Why not buy a slotting saw (cheap!) and do it properly? What's a "translation screw"? (1726)
Crosslide sleeve
Does the sleeve in which the cross slide screw runs on the 9" SB lathe unscrew from the saddle casting the way it does on the larger lathes? The 13" lathe has hex flats on the sleeve where it enters the casting to make the method of disassembly very obvious, but the little one does not. My clever stepper motor mount (clamps around the end of this sleeve just behind the micrometer collar) blocks the slide from retracting the final, badly needed 2 inches. Since I'm making a new screw assembly anyway, I am tempted to try to replace the sleeve with a longer one, so that I can obtain the full designed range of travel even with the stepper mounted. Failing that perhaps I'll try to redesign it with just a hose clamp band instead of the current bored block of aluminum with a tightening screw across a slot. Chris (2189)
The bushing (what you call a sleeve) is RH threaded into the saddle. Sometime you will encounter these with a small hole (drilled in the periphery at 6 o'clock radially) for a pin wrench to act upon. One way to unscrew the bushing, if you have removed the saddle from the lathe, is to strip out the ball crank handle, dial, and screw and then grip the bushing in a vise that has its jaws well padded (with lead or leather). Then the saddle can be unscrewed from the bushing without marring the bushing. Webb (2190)
I think I may have found a way to make a new clamping motor mount that does not completely encircle the boss leaving the top clear, which would avoid having to make a longer bushing. But if I do need to take it out, I'll just make up some copper pads for the 3-jaw and tighten it down on the bushing, then use it as a wrench to unscrew. Or I might use my old motor mount as the wrench. Chris (2191)
Chris, If you are going to use the chuck mounted to a threaded spindle, you will with all probability just unthread the chuck. Plus the clamping pressure needed might spring the jaws enough to impair the accuracy of your chuck. I understand that you are trying to get a good grip on the bushing to unthread it. If you had a collet big enough, well maybe. But the lathe is a precision instrument and should be treated with respect and care. Damage or your accuracy may suffer if you don't. I don't intend to chastise; but I do think using a well padded vise is the way to go. Or drill a shallow hole in the bottom of the bushing and use a pin wrench. Webb (2192)
Chuck would not be on the lathe, rather the part I'm trying to unscrew from the carriage is. But I don't think I'll need to take it off now. Chris (2193)
Worn cross slide on saddle of Heavy 10
I have been using and restoring a Heavy 10 (vintage 1941). The cross slide of the saddle is worn in the middle, such that: If I tighten the gib so that it is snug in the middle, it is too tight to travel to either end of the range; conversely, if I loosen it enough so that it can travel across the entire range, it is very loose in the middle. Because I have a Bridgeport mill, I am planning on remachining the dovetail ways of the saddle in the following manner: 1) Let the saddle rest on a pair of cylindrical rods of the mill, indicated carefully for height and parallelism; 2) Using a 60-degree dovetail cutter, take off just enough of the casting to expose fresh metal from the cross slide. 3) Add a shim to the crosslide gib as needed. My question is, does anyone have experience and advice for me in doing this? Also, I have heard of putting in Teflon or "Rulon" strips to the gibs, for better sliding action. I don't know anything about doing this. Jon (2306)
Don't take this wrong as I mean well. Don't take the mill to your cross slide as you will ruin it. It needs to be either reground or re-scraped. Look for someone that can do that for you. The mill isn't accurate enough to do a cross slide on a lathe and you would be doing a great disservice to the person that buys the lathe. Yasmiin (2307)
Cross slide nut?
9"/10K cross slide. How does the cross slide nut get attached to the slide. I have a slotted set screw and the slot is gobbered. I am afraid to wrench too hard. Is it left hand or right hand? non-taper style nut (flat topped). (2601)
I am assuming that you have a 9" or 10K lathe with a non-taper type cross slide. The "set screw" in the center of the cross slide nut retains the nut in the cross slide casting. the casting has to be removed from the saddle before you can remove the nut. After the casting with the nut is removed from the saddle, loosen the "set screw" and twist the nut back and forth while pulling the nut out. The "set screw" has a conical point and as the screw is tightened down, the wedging action of the conical point bears against another part (called a "pin" by SBL) and pushes it out perpendicular to the set screw and this forces the pin out against the inside of the hole bored in the cross slide casting; locking the nut in place. Webb (2630)
It's the set screw that's gobbered up pretty good, and I am afraid that the slot will shear out causing me to resort to e-z-outs. Is the set screw right hand or left hand thread? I am thinking I only have one shot to get it out. dp (2631)
The set screw is right hand threaded. I don't know the thread size off the top of my head. But remember it is a standard fine thread. Webb (2633)
I think I did it good. plenty of liquid wrench and the slot of the screw is shot. I think its ez-out time. the screw is right hand? could someone try to remove theirs? while you are at it, measure the threading too? I would appreciate it. dennis (2753)
Dennis, I have had mine apart. Actually I made new bronze crosslide nuts for both my lathes. They are right hand threads. I think it was 1/4 x 18 or at least some standard thread. I borrowed a tap from work to make the threads. Glen (2754)
The LEADSCREW nut is 18TPI? Mine is 3/8-10 acme if memory serves. Sorry I tuned into the middle for this thread, what am I missing? (2755)
He's referring to the retaining set-screw in the top of the cross-feed nut. Paul R. (2757)
I think it was 1/4 On a cross or compound slide I think a thread is used that makes the dials come out even to 1/1000 or a good even fraction. I have seen 25 tpi (same as a micrometer) or 20 tpi (the cross slide on my old 6 inch Atlas. My new HF minimill has 16 tpi and the strangest dials ever seen to get that odd .065 inch included. I would rather have metric as a hand held calculator can convert that if they could not make a reasonable thread on the slides. The Smithy that took up room in my shop for a short time had dials that were marked as approximate .049/ division. What good is an approximate division value? John (2788)
I was talking about the set screw for the cross slide nut not the thread for the nut itself. Glen (2795)
Refurbishing a worn cross slide
I have an old Heavy 10 (made in 1941), that had a very badly worn cross slide. The saddle casting was worn so much in the middle that it was impossible to properly adjust the gib. If I tightened it so that it would be snug in the middle if its travel range, then it would be too tight to travel to the extremes. The dovetail ways had been worn to an hourglass shape, and the flats had been badly scored and scooped in the middle. Some of you with older lathes may have experienced this problem. I have heard from a machinist that this is a very common problem. I have remachined, sanded, and scraped the cross slide ways, and took photos of the process to share with this group. The photos are attached: 1. I set up the saddle casting on a Bridgeport vertical mill. The vee ways of the saddle rest on a pair of 3/4" rods. The rod on the right hand side sits on a piece of aluminum with a vee machined out of it. This is supposed to keep the saddle aligned properly so that the remachined surfaces will be perpendicular to the vee ways. The rod on the left hand side rests on a flat piece of aluminum, milled to the height that will make the saddle level. The saddle is clamped down with two pieces of wood. To avoid flexing of the saddle casting, I didn't want to exert undue pressure. 2. The saddle is checked for alignment with a dial indicator. Both the dovetail ways and the flats are indicated in. 3. I machined the surfaces with a HSS dovetail cutter, at a speed of 150 rpm and a table feed rate of about 1inch per minute. (2796)
After machining the saddle casting, I did a similar process to the compound rest base, and checked for squareness back on the lathe bed. Attachment: (image/jpeg) 4.checking squareness on lathe.JPG (2797)
(continued from last message) sorry about that. The picture captions got left out from the previous post: 4. A 6-inch parallel is held in the 4-jaw chuck, and a dial indicator is used to check for squareness with respect to the spindle (the chuck must be rotated by a half turn to verify that the parallel bar is in correctly). 5. This is a home made scraping tool that uses a TPGH-322 carbide insert. This is good for making light finishing cuts on the flats of the ways, and also for scraping under the dovetail ways. 6. The relief angle of the TPGH insert allows the carbide to scrape while its face is perpendicular to the machined surfaces. I found it necessary to use one hand to press the shaft of the tool against the dovetail surface, so that it would bite into the cast iron. **************************************************************************** Here are the captions for the last set of photos, which are attached to this post: 7. After sanding off the machining marks and a few iterations of scraping, I flaked the flat surfaces of the saddle, using the "bump" method. This is supposed to make it look as though the saddle was refurbished by an experienced professional, rather than a novice like me... 8. The compound rest base was remachined and sanded in a comparable manner to the saddle. Only one side of the dovetail was remachined, since the gib protects the other side from wear. For setup in the mill, the gib was held in place by magnets, and the gib surface was indicated in. The photo also shows a brass shim I made to compensate for material removed by wear and machining. The trough (surface in the photo where the gib rests) also had to be milled to compensate for removed material. 9. Checking for final alignment, with saddle reinstalled on apron, complete with taper attachment and cross feed screw. I stopped scraping once the indicator showed less than +/- 0.0005" variation over the cross slide travel range. I am satisfied with how this project has turned out. The lathe works much better than before. Jon (2800)
Cross slide nut
How many people are interested in 'new' cross slide nuts? I am going to talk to a friend who works at a company that makes thread mills to see if I can swap him some time on the CNC tools. (they make the coolest thread mills. they have a widget to show how good there tools are: they have a nut that works on both left handed AND and right handed threads. I do not lie, I have witnessed it.) I would like to collaborate with others in the group to get some sort of 'improved' design over the stock nut. it would be nice if we can figure out a way to make them simply backlash adjustable. I was thinking ala Bridgeport style, but that might be too complicated. Otherwise, I am thinking plain simple basic nuts and bosses. I am thinking or running a bunch of 'rough' machined parts: 1" square stock that will be cross drilled and acme tapped. The boss turned oversize. final turning of the diameter and drilling and tapping the setscrew hole and 'pin' hole is up to the user. Costs: cheap. Depends mostly on material selection. the CNC time would be free (may lunch and a twelve pack) and packaging and postage. Any one interested? collaborators? we could even make compound nuts too. Dennis (2863)
I bet everyone, but WHICH one are you going to make. I have a heavy 10. I also need a GOOD cross slide screw for a taper attachment. (2864)
I'd sure like to know how to make it backlash-adjustable. Can you explain how the nut on a Bridgeport works? (2866)
Marty: what are the specs on the nut you need? I have never taken a part a heavy 10. lets make a list of what we want and see how many different parts we come up with. Then I can go in educated like and not waste a lot of time in the shop. What about making them adjustable? we threw it around a while ago. The Bridgeport x-y nuts are a bit complex, they are barrels with a slot cut 3/4 through in the middle. Adjuster screws on the housing flex the nut to take up the backlash. If we can come up with a simple modification to the nuts, I think we could make something serviceable. dennis (2867)
Dennis, That's a wonderful idea. Count me in. If we could just produce, like you say, a piece of rectangular brass/bronze bar stock with an offset ACME threaded hole and leave the finishing up to the individual, that would be great. If there's enough "meat" left, that would give us options for designing the backlash compensation mechanism. I've got a few designs we can kick around. What size does the compound use? I'm sure my lathe needs a replacement compound-feed nut too. A replacement cross-slide lead screw is something the lathe-owner can machine with minimal tooling, but the nut has been (at least for me) a "tough nut to crack". Let's do it. I'll buy some beer ;-) What can we do to get started on this? Who knows of a good source for the stock, and what material should it be? I'll put together some of the nut designs I've seen and we can critique them. Paul R.(2868)
It seems I must chime in and correct some misunderstood things about cross slide feed nuts and the screws that work with them. First the taper and standard cross slides do not use the same nut. The nut for the taper slide is flat on top without the locating boss the standard one has. The feed screws from SB come as an assembly with all related parts such as handle, dial, mounting bush and feed nut along with the screw. If you look at the catalog page you will see that when you order it, it is an assembly number and all the parts marked * come with it as well as the feed nut. Next when using the taper attachment you remove the screw that connects the feed nut to the cross slide and all of your diameter adjustments are made with the compound feed as the cross feed is disconnected. Finally thread milling on this thread will be very difficult if not impossible because of the thread size and pitch involved. I have a quote out for a tap right now and they all have told me that with this thread a tandem tap is not possible as it would be to weak and break. Measure it out like I did and note that there is not sufficient room for a 10 pitch acme thread cutting tool to pass through the core of the thread. If you can not thread cut an internal thread you can not mill it either which means using a tap. Acme 3/8-10 taps are available but because of the coarse pitch and small diameter a combination tap is not possible. It will require two taps, a roughing one and a finishing one. I am trying to get a quote on them right now and will let all know the price when I know. I am also including two small articles on backlash adjustment from ME in the 60s by Geometer so that this process can be better understood by all. JWE (2869)
James, Thanks for the articles from ME. What you said about the details for cross feed screws and nuts may be true for SB's 9-inch lathes, but I don't think it is the same for their Heavy 10's. The parts list for the Heavy 10 is different. See attachments. My suggestion for doing taper turning with a short screw was to unscrew part #16 in the diagram (C.F. BUSHING), because it is easier to do that than unscrew the cross feed nut. (The C.F. nut is labeled as part number 55 in the sketch, but listed as #50 in the table. It looks like SB made a couple of typo errors for that page). With the longer screw, normal taper turning is done by disconnecting the rear hex nut, item #16 in the sketch. These are my observations of the two old Heavy 10 lathes that I have. On one of them, it appears that a previous owner switched out a short screw for the original long 2-piece taper attachment screw. Jon (2871)
Jon The 9", 10K and 10L are all similar while the heavy 10 is a completely different breed of cat. I hope all realize that fact and do not try to mix and match parts between them. It is like when I got my bed turret in the late 70s, someone had put a spacer plate on the bottom of it to use on a 12 or 13 inch machine. The dealer had it sitting around for years and when I expressed interest in it the joy on face at some one wanting to buy it made him very generous in the way he priced it. The same as for the follower rest I got last month on Ebay, I knew from the pictures it was for a 9" or 10K but because it was not listed that way I got it for about 1/3rd what they normally go for. What any of us say can only apply to the machine we have experience with and all comments and suggestions need to be referred to the catalog parts list for the machine in question or the newbie with out experience will be very quickly confused. JWE (2872)
I believe that the Heavy 10 is the same thing as the 10L. The 10K is sometimes called a Light 10. The original post about cross feed dials and taper attachment was for a 10L. That is why I replied with info for a Heavy 10. (2873)
I have followed the postings about the differences between the light 10, 10K and Heavy 10/10L machines. I have found that the easiest way to keep them straight is that the Light 10/10k machines are simply 10" versions of the time honored 9" machine. Southbend started making them back in the late 60s or early 70's, as I remember. The 10k has the spindle size of the 9", so is limited to using the 3C collets, where as the Heavy 10 has the larger spindle that take the 5C collets. I have found that some small parts do interchange, as I had a 9" when I first purchased the Heavy 10. I have been tempted to bid some 10" parts on e-bay for my Heavy 10 and always need to clarify with the seller just what he is selling, (which many times is not the case). Hope that this helps. Keith (2874)
Jon What I have seen and worked with myself have been 9" and 10K 3MT spindle 1-1/2-8 thread uses 3C collets 10L 4MT and I think 1-7/8-8 spindle uses 4C collets Heavy 10 5 MT spindle 2-1/4-8 or D1 spindle uses 5C collets The 9" and 10K share almost all parts and are very hard to tell apart. The 10L is a in between machine that shares some features of the 10K with a larger spindle. The heavy 10 is more similar to the larger machines in size and design. JWE (2875)
The 10K or Light 10 can use either the 3C collets with the taper sleeve adapter or the 6K collets (direct fit no taper sleeve needed). The 3C have about a 1/2 max capacity and the 6K have a 5/8 max. capacity. The 10K spindle has a large ID chamfer and a (drive) pin that permits the use of the 6K collets. SB 9's use the 3C collets only with the use of a sleeve adapter. Tom (2876)
James et all: this is exactly the process I was hoping to go with the group. I think this Endeavour is best described as a group project. there are many members out there who have more knowledge than I do. I just have an idea and maybe the access to the tools that would make the Endeavour reasonable and economical. we we can work together then we all benefit. i hope that we can discuss what has to be considered and collectively find the solutions. I think that we are on the right track. in fact it sounds like there are going to be 4 solutions: 9"/10K taper cross slide and non-tapered slide, and then the same for the 10L. as far as threadmilling, I have confirmed that they can in fact treadmill the 3/8-10 LH acme. Its not going to be the usual treadmill however, and it might take a bit of work to fine tune, but that's for me and my friend to work out. I am willing to take the time and effort to try it. at this point, what we need to collectively do is identify the size and pitch of the threading of the different ones we want to make and then 'design' the nuts. I am happy to draw and detail the nuts on CAD. If anyone out there has a head start then great, we can use that too. I am not looking to mass produce a bunch of finished parts, but make the nut in a sort of kit form for list members finish and to better their machines. I look forward to the groups replies. dennis (2877)
My new MSC catalog [which is at work, and I'm at home as I write this] has some Acme taps that look like 2 taps joined end-to-end...the front part makes a 60-degree thread form it looks like, and the back part makes that into an Acme, each tooth is a little closer to an Acme and a little less like a V than the last. Is this what they call a 'tandem tap'? (2878)
Well, here's my idea: make the nut in 2 pieces, joined in the middle by a thread larger than 7/16-10 Acme but very fine, I dunno exactly what, like say 9/16-32? Sort of like the threads in the middle of those little stainless canisters like my Grandpa had his nitro pills in, it unscrewed right in the middle. You unscrew the two halves of the nut apart to take up endplay; each half only wears on one face of the thread. Hmm, big enough joining thread may not fit under the cross slide. How about make it in two pieces with the top stud on the one piece and both pieces having little ears sticking out to the sides, one's ears threaded for about a 10-32 capscrew and the others having clearance holes for same; you screw the capscrews in to draw the two halves of the nut together to take up endplay. Again each half only wears on one face of the thread but it isn't worn out until the threads are completely, totally gone. What do you guys think? (2880)
Brian It sounds like yours is either a later machine or a different model. If it is .430 that would be 7/16 and thus larger than mine and different than the other two 9" machines I have worked with. The two PDF I sent earlier today from work showed several different methods for doing adjustable nuts for taking up slack. What will probably work is some combination of what is shown in the two of them. I will really need to take my machine more apart and see how much room is there to work with. As far as fitting things up the feed screw is the least part of the problem. The nut is going to be the most work and effort to get right. Every tap maker tells me that 3/8-10 in a Acme tap is not doable unless we go to the low profile form. 7/16-10 will probably be achievable. The question is if those with 3/8 feed screws would want to go to 7/16 or even to 1/2 inch. In that case a 10 tpi Acme tap will be fairly easy to get made at a more reasonable price. From the price breaks for the 10x1.0 mm taps I got before for the 7x group the best break came at 50 taps. So to get a good price we will need to decide on what size to go with and if there will be enough that want one to get the price down. The same will hold true for the chap that can thread mill nuts he will need a common size to get his setup and material cost down to a reasonable level. If we do this the question now is what size do we want to do the thread in? JWE (2883)
Brian, This is a tandem tap. The 60 deg front part is to rough out the bulk of the material and the rear acme form then shaves the final acme form. I purchased one from www.Tapsdirect.com prior to christmas for my half nut rebuild. The cost was about $105... the best price I could find. I did pick up a thread about an acme plug tap for $35 from MSC. However, I was told that the tandem produces a much better finish. From using the tandem I also would say the plug will tap much harder. Ed (2884)
Dunno WHAT I have here. SBL tells me it's an "R" from the S/N but nothing on it matches my old book reprint [book #17-L] for an "R". I think this is a "Workshop" lathe which is in book 19-C which I don't have. It is a horizontal drive "C" with the motor drum switch mounted where the QC box would go, manual change gears, a single-neck idler banjo, non-detented [bolt-lock] tumbler and 6:1 compound gears with a 118T screw gear. SBL sent me the original card for the lathe 3 s/n's ahead of mine, and that one was shipped to Brazil in '37. The large-dial replacement carriage I snagged fits; it is marked "S102" and "J130" under the cross slide, and the underside of the cross slide is marked "J130". This is the one with the homemade dial bushing, crosspinned small CF bushing and trashed leadscrew with ball thrust bearings. The original carriage is marked "52" under the cross slide and has small dials. The CF screw for the large-dial one is 10TPI, .439 OD over the unworn part of the thread. I haven't disassembled the original small-dial carriage to measure, but the leadscrew looks the same OD to my eye. Remember mine is a pre-fire lathe; I'm told that is somehow significant. None of these numbers match either of my books. Maybe someone on the list can shed some light. I suspect my large-dial carriage may actually be a 10L or 10K carriage. I dunno. They're both no-taper-attachment. (2886)
James et all: as far as costs for the setup and making the proper thread mill and making of the parts, there is no issue there. as he and I will be making them after hours on a weekend. i.e.: no overhead if you understand my meaning. The only real costs at this point will be the materials cost. i am willing to float a length of sae bronze or brass. I am going to go scavenging too to see if anything can be had. my friend was going to check to see what masters were inventory. they have 2500-3000 thread masters in stock. he thinks that they might even have one already made! the process is really neat. They custom make their own diamond grinding wheels for the carbide and grind the profiles on the inserts and solid tools. The master grinding wheels are all kept in this huge room that reminds me of a old data storage center or film archive. I shouldn't say much more, I don't know what is trade secret. What we need to do next is 2 part. 1. determine the geometries of the basic stock nuts that we need to make. Which means that for each type of slide and machine size, someone has to make a drawing of the part. I suggest that we make sketches of the stock assemblies and the go from there with modifications. I think it also be prudent that we note any markings on the nuts that we are measuring and maybe the cross slide unit code numbers that are stamped on the casting. 2. come up with the clearances and geometries that we have to work around as constraints to design an adjustable nut. I have attached a sketch of the nut that I have which came off of my 10K as an example. I will measure the side and bottom clearance later. I used cad since I have use of it. you don't have to use it. hand sketches that can be scanned are fine. you can also fax them to me if you need. I will be happy to redraw them in cad. SOMEONE PLEASE CHECK MY WORK! i have not yet removed the cross slide screw, and I am measuring a REALLY worn out nut. so worn in fact that the threads look like they have serrations. the side of my nut appears to have the letters "N 11" stamped on the side. I will remove it later this week. you are correct in your assumption that we need to figure out how much clearance we have to work with to make adjustable nuts fit. i would also suggest that we consider how they will be adjusted. It might be wise to use some sort of hex head screw that would be adjustable from the rear of the cross slide with a long Allen wrench. so to those following the thread, some one with a 9"/10K please verify my sketch. Someone else who has their machine apart please sketch and post the other nut styles. please include any part number marking so we can classify the nuts. We will need: 9"/10K taper cross slide nut heavy 10 std. cross slide nut heavy 10 taper cross slide nut someone was after a compound nut (marty?) how about a sketch of that? any other sizes of lathes out there? c'mon guys there are like 400 or so of us here. someone else must need/want a new nut or two. I look forward to your responses. Dennis (2887)
A workshop C has no worm and worm wheel or clutch in the apron, power feed is via closing the halfnuts, manual change gears. My Workshop C has the single arm banjo, it is S/N 61150. It also has the 118 tooth screw gear and locking bolt style tumbler. There is some question whether this lathe is from 1936 or 1939. I haven't called SB to see what they say, I just never think of it during daylight! Perhaps all or some of your parts were swapped between several lathes or onto a new bed if the S/N doesn't match up with the rest of the parts. Stan (2888)
Denis: I think that you have a great idea here, and I am very interested.( read "very" with large flashing bright letters!!) If you used a large enough profile stock and offset the thread as you indicated I suspect that you would only need two sizes to accommodate 9/10k or 10L lathes. I am going out to my shop a little later in the morning and will try to confirm the dimensions off my very worn non-taper 9"A model. I was wondering if it might be appropriate to also locate a supplier of LH acme precision threaded rod, and have the nuts sized to fit. There have been several recent articles on repairing feed screws using stock rod. I know that my lathe needs both screw and nut, so it might be worthwhile to at least make the info available. FWIW, I recently made a 1/2x 10 RH acme tap to replace the down feed nut on my Atlas shaper. I used the dimensions from "Machinery's Handbook". The tap is a little ugly but it made a serviceable ( much better than what I had) nut. It wasn't too hard, but I don't work to the tolerances that most of the members might want. Pete (2890)
Got called away from my computer; dunno if my previous post posted or not. Your lathe sounds just like mine, which is s/n 75045 and was made in 1937...so yours was probably made in '36. The large-dial carriage I bought separately later. There is another parts book, #19-C, I need to acquire I guess. (2892)
Denis: I measured my 9" A model c-feed nut, and found a couple of minor differences on the dimensions 1) length of nut is 1.165" 2) max width of body is .710" 3) length of stem is .860" This might be accounted for because it looks like the nut was machined from a bronze casting. If the new nut was made based on a block of material 1"x1 1/2'x1 1/4" the end user could machine to the dimensions of what they have. Pete (2894)
I am interested in how you made your acme tap. How did you relieve it and what metal used and hardning method. I have some other machines requiring nuts and don't want to spend a fortune in new taps. I bought a cross slide assembly (SB 13") that was in great shape but the nut was shot. Decided to go whole hog and purchased from MSC a length of LH acme thread ( other site threads imply precision threads hard to find and probably pricy). I made a whole new front end including the gear section and pined on the MSC thread. Also ordered a LH tap and used it for finish cut of a block of bronze after I lathe rough cut the start. I used the old nut and the new nut on a piece of new acme screw fixtured in my BP mill and indicated the sides in order to OD turn with a boring tool the stem OD to the correct centerline. It fitted nicely the first go and outside of the cost of the pricy tap was a good deal and is now working nicely in my late model SB 13 with a 7' bed. This worked fine for me because the slides were not worn too much. I expect if the slides were redone a correction in the centerline of thread to round top might have to be made. Probably something a person buying an original SB nut might run into. Walt (2895)
There was a short article several years ago in either the Home Shop Machinist or Projects in metal that showed a tricky way to make an adjustable cross slide nut. As I recall it made one part of the two part nut threaded on the outside one or two more threads per inch than the lead screw. This part was screwed into a mating receptacle on the cross slide frame. This exterior threaded part was turned in or out a little to adjust the back lash. I will try to thumb through my stack of past issues and find it. Someone else may remember the article and have quicker access to it. Dallas (2907)
I think that the self-compensating leadscrew nut that you are thinking of is like the one found at this link. http://www.kerkmotion.com/Pages/axial%20take%20up.html Take a look at their other anti-backlash solutions. There are some good products here. I have not yet attempted to make these out of brass or bronze yet, but it seems like a great idea. Keith (2965)
I found the article in Projects in Metal April 1998 titled "An adjustable cross slide nut" that I remembered seeng. It describes a method of making a cross slide nut that can be adjusted to zero backlash. The scheme is to bore 1/2 of the existing acme thread out larger, and thread this larger bore to 9tpi LH vee thread. A short sleeve is then made threaded both on the outside and inside. The outside is threaded to 9tpi LH vee to mate with the nut body. The inside is threaded 10tpi LH to run on the lead screw. The sleeve is castleated on a thin flange on one end of the sleeve. This allows the sleeve portion to adjusted to zero backlash and locked in place using the slots in the flange. As wear occurs another notch can be taken up on the adjustable sleeve. Dallas (3050)
I wanted to update all those interested in the cross slide nut adventures....i am having success in making the parts. it will be a couple of weeks or more to go. 1. I have decided to start by making plain simple, similar to factory nuts. 2. we successfully thread-milled test holes of both 3/8" and 7/16"-10 LH acme. I checked the 7/16 against the screw that I have removed from my machine. as my nut was so worn, it is like night and day. my screw is worn in spots, so I do have a bit of play, how much i won't know until I finish making the nuts. it is acceptable. 3. the process of making the nuts: a. we are turning down round stock, 932 bronze (replacement to SAE 660). b. chucking the bar stock in a CNC lathe with a bar feeder. c. turning the boss to a shoulder and then dressing the big end of the nut. Final od on the boss I am leaving at 0.688, which is 1 thou over. reasoning: I don't trust the measurements of my cross slide nut hole as exact. I think people can easily fit the nut to their cross slide with a bit of emery papering from here. d. then we are center drilling and chamfering the pilot hole for the set screw. the set screw in my nut is not 1/4-28 as we thought by 5/16-24. i am making all to 5/16-24. next we cut off the part and caught it in the thing i can remember the name of. Its a chuck that spins at the same rpm as the stock chuck and grips the part before it is fully cut off. e. move over to a old hurco mill and then cross drilling the pin hole and an index hole to jig the nut for thread milling. i ended up deburring the part at this stage. f. the moving to a machining center, we are chuck the nuts in a CNC 5-C collet indexer and spot facing a couple of flats for the pilot hole for the acme thread. g. threadmilling the acme thread. h. optional: roughing out the profile of the nut taperer body. Since the piece is chucked and in the mill, I can rough it out. users can finish from here. 4. hangups: we did not have a the proper/ a good collet to chuck in the indexer on the machining center, so the blank wasn't held tight in the collet. End result was that the pilot hole and threading was not exactly 90 to the boss. By turning the boss to a given collet dimension, we could produce exact results. I am ordering a few collets this week to try and get a better grip on things. I am getting a few emergency collets too so I can make the right one if stock ones don't hold right. comments: I am amazed at how nicely the bronze is finishing. Lots of coolant, SHARP carbides, and precise feed rates. leaves me a bit to be desired on my manual lathe work. Repeatability always amazed me. programming the tools took less time than I thought. Realistically, it took 30 minutes to write the code, and another 10 to tweak the program with tool offsets. Need to bump the tool a quarter thou? no problem. Just push a few buttons... viola! cylce time: after we got things going, it takes 3 minutes to turn the blank and cut it off. about 5 minutes to clamp, drill and remove the blank. It took almost 4 minutes to bore and thread. I spent more time walking from machine to machine. Only regret aside from not having the proper collet is that in the lathe, the gripping chuck when it catches the cut blank mars the finish a bit. It leaves a scuff mark. it is certainly a cosmetic flaw. I don't think that anyone will complain that the mirror finish on the boss is a necessary feature. next steps: once I get the collets I will be able to finish. I will send out 5 nuts to 'beta-testers' for review and comment. if the nuts pass inspection, then I will send them out to those interested. Cost: materials and other consumables is just under $6/nut. I am replacing the end mills and drills and taps that I am using at the shop. for now the treadmill is free. I figure that at the end, another $4-$5 for a box and shipping will bring the total up to the $10 range. I am not charging for my time. future projects: compound nut: I have not yet taken apart my compound to get at the nut. I haven't figured out how to. I will do it, but in the meantime, can someone, ANYONE PLEASE confirm that it is 3/8-10 LH acme? that should be a simpler part to make. Backlash adjustable nut: I think I have figured out a simple mechanism to adjust backlash. It involves a bit more machining work. I will draw it up and post it to the list for review and comment before entertaining that endeavor. Undersize nuts: since I do have a worn screw, I am going to try to make a nut or two under spec to see how it works to take up play. Not sure if this will work, what I really need is a treadmill with a profile that is not symmetric so I get fatter valleys and thinner valleys to compensate for the worn screw. For now, progress. Slow but sure. I will try to take pictures of what I have and post them to the list. dennis (3155)
Excellent news Dennis. Your efforts are appreciated and on behalf of those of us many thanks. Keep us posted on your progress. Hope you still have me down for one! (As I mentioned in a previous email. Its ok for me at least to do the final work, the threading is the tough part). Marty (3160)
What I meant to say is that to properly make a nut that will compensate for a worn screw thread is the threads on the nut need to be 'tighter:' wider threads and the valleys a bit narrower. to do that I think that it needs a custom grind on the cutter. undersize nuts: since I do have a worn screw, I am going to try to make a nut or two under spec to see how it works to take up play. not sure if this will work, what I really need is a treadmill with a profile that is not symmetric so I get fatter valleys and thinner valleys to compensate for the worn screw. (3161)
A few people have emailed me to ask what the status is on the nuts. the status is i am at the mercy of paying work to get more machine time. the machines have been tied up on a couple of large runs and we did not want to tear down and re-set up the fixtures. those jobs should be finished up this week and hopefully i will be able to get in on Sunday. thanks for you patience dennis (3528)
IIRC, a while ago someone on this list was working on making some replacement cross slide "nuts". Is this true? Who do I contact about this? I had my crosslide apart recently and the wear on the nut was amazing. I can hardly believe the thing works. Jeridiah (4283)
Dennis Pantazis is who you need to talk to. I was lucky enough to get the very first nut from him about three weeks ago. I didn't get it installed until last night. I was busy (My son is now two weeks old! ... And the concrete for my workshop was poured this morning). My old 1928 9" Jr. lathe is a bit different than the 9" Workshop lathes, and I had to mill the nut down to match the original height, drill and tap the retaining hole deeper, but it fits wonderfully. When I bought the lathe there was about .085" (almost a full turn) of slop in the crosslide. I replaced some of the worn washers on the screw assembly and took out .035" of play, leaving me "only" half a turn of slop. After installing the new nut, the play is under .003"! It feels like a new machine. -Mike (4299)
Yes, I am the guy with the cross slide nuts. I have made the first batch, sent them out to the beta testers. I have gotten positive feedback from a few people, haven't heard anything from others, and i am still waiting for some to send me $$$. if those who have dibs and have not sent me monies, then I will put them on to the open market next week. in my case I went from about 0.090" of backlash (yes, almost a full turn) to about about 0.007 mostly due to screw worn at the worst place. I have been meaning to take some pictures to post, but have not had the time. Maybe over the weekend. Future batches to come, just don't know when. dennis (4308)
Dennis, What model did you make the nuts for? I have a 10k with taper attachment. How did you cut the threads? My nut is LH 7/16 x 10 and the cheapest I can find a tap is $179. If I make the nut can you tap it? Jay (4313)
May I suggest you contact Tracy Tools of Dartmouth, South Devon, UK phone No her in the UK is 01803 833134 fax 834588 I have in the past bough left hand taps from them for lead screws for about say 16 dollars US at our shows here and that even if post a packing cost more cant come near your price. Phil (4315)
Here's the report on my 1941 9" model A cross-slide nut replacement. After finally completing the machining of my 5" and 6" replacement chuck back-plates, and squeezing in a few minutes this morning, I have a wonderful new cross-slide nut installed on my SB. I had to remove about a thousandth off the boss diameter, a couple of thou' off the top and ream the cross-pin hole to 0.250 to fit my old dowel. I still have about .007" play in the thread (MUCH BETTER), and plenty more in the bushing, but what do you expect of a 60+ year old lead screw. When I get around to fixing the bushing, I think I can live with the old girl. Many thanks to Dennis on a fantastic job! Any thoughts on doing a compound nut? Paul R. (4317)
I put a picture of the cross slide nuts in the photos section. the two on left is finished regular style nut. As you can see, its finished nut. Finished nut includes new 5/16-16 set-scew. 'puck' on the right is for taper style nut (as I still don't have a taper style nut to go from), or a blank for those who want to roll their own. Both types have the 7/16-10LH acme thread milled. dennis (4323)
I have a Southbend Fourteen with a taper attachment and I was wondering if you can make some cross slide nuts that would fit my lathe. The manual lists the part as a Cross Feed Nut, 5/8 - 8 Acme L.H and the Compound Rest Nut, English Thread, 1/2 - 10, Acme R.H. Please let me know if it possible for you to fabricate these nuts, if not, I will give it a go on my own and would appreciate any help. Ray (4338)
Would you like some money for a nut for a South Bend 9" lathe? I can also trade you a beta set of brass jaws that fit steady rests for the 9", 10K and 10L lathe. South Bend wanted $35 per jaw, I'll trade you 3 for 1 nut. Ted (4433)
Heavy 10 Cross Slide Thread Pitch
Off hand does anyone know for certain what the lead and size is of the crosslide screw for the Heavy 10? (Later model double tumbler). Marty (2966)
On mine, (old, 1940's model Heavy 10, single tumbler) the diameter is 7/16" and the pitch is 10 tpi left handed. You can be sure the pitch is 10 tpi when the dial has 200 graduations of .001" (indirect reading), or 100 graduations of .001"(direct reading). If the dial has 250 or 125 graduations, then its pitch is probably 8 tpi. In general, you can correlate the pitch with the dial markings in this way [i.e., 1 inch/(8 revolutions) = 0.125" per revolution]. On the parts list from South Bend, they do not distinguish between newer vs. older models for the cross feed nut, so I believe yours should be the same as mine. Jon(2980)
Replacing Cross/Top Slide Handle Nuts
So now that we know how to get the bushing out, how do we get it to stay in? There doesn't appear to be a setscrew or anything for locking it in, and I'm a little hesitant to loctite it for fear the loctite will get in between the bushing and the leadscrew...when I back out the leadscrew the bushing backs off. (2996)
On both of my SBs it is threaded in, you just install it tight. If the threads are weak for some reason, you could use low strength loctite, but I haven't had to do this on either of mine. You can always wrap the bushing in brass shimstock and grab the shimstock with medium channel locks to get a better grip, although a few gentle taps on a closely fitted pin dropped in the provided spanner hole is probably adequate - its worked for me so far. I wish they had provided flats on this part for the 9 inch lathes, as they did on the 13, next time I have it apart I may just mill flats to make tear down easier. Either that or make the proper spanner. Stan (2997)
Hole In Cross Slide

Is the hole you are referring to the one in the cross slide right above the bushing for the cross feed? That hole in the cross slide (mentioned in the posts about the pictures of Rick Kruger's lathe) is for the Threading Stop. If you look in your How To Run A Lathe by South Bend Lathe, you will see a picture of the threading stop and how it is used. Webb (3013)

The hole I'm referring to, is drilled from the top of the carriage; marked [on oiling.jpg here on the server] as 'feed screws type oil C oil daily'. I'm guessing you're referring to the one drilled horizontally into the end of the movable part of the cross slide?(3014)
Brian, Yes, you are correct. That is what I was referring to. I think I was mislead by the difference in terminology that people use to refer to different parts of a lathe. To me, the Carriage is the total assembly consisting of the compound, cross slide, saddle and apron. The Cross Slide is the moveable casting which mates to the dovetail of the saddle. And the Saddle is the casting that slides along the bed. So, when you said "I notice the little oil hole in the top of your cross slide at the front..." I though of it in my terminology and misunderstood what you were indicating. To me, what you are referring to would be the little hole in the top of the saddle. I apologize for my misunderstanding. Webb (3020)
No apology necessary, just trying to keep the terms straight. it seems that what SBL calls a part, many people have a different name for...for example, SBL calls the casting a saddle, but many others use the term to refer to a swaybacked form of bed wear. Lathes are truly a subject where one pic is worth 10K words. (3021)
Unknown hole on SB9 cross slide
Rick Kruger wrote: It is for the feed / screwcutting interlock pin. With the half nut clamp handle taken out, the pin slides across the big hole and out through the side of the apron, through the hole you mention. This is the pin referred to during the reassembly of the apron: http://steammachine.com/hercus/page5.html Can anybody tell me what the horizontal 3/16" blind threaded hole in the end of the cross slide is for? Cheers Charlie (4144)
Cross slide blind hole: Which end? The near/dial end? If so, is that not the threading stop hole? I don't have one, never use one, but am gonna make one, now that I understand its operation. Takes one thinking step out of the single point threading process. Rick K. (4145)
Not Exactly, Rick. And on my list too. It gets kind of dicey for me when I have to back the cross-feed out more than one turn. Sometimes I loose track and have to go back and verify. You tend to loose you rhythm then. Paul R. (4147)
Rick Kruger wrote: Yes, its at the dial end, I thought it was for an oil nipple but probing with a scriber showed it didn't connect with the oil hole drilled down from the top. Charlie (4153)
T-slot crosslides
I was looking at T-slot Crosslides at http://www.sc-c.com/metallathe/index.html and was kind of wondering if it would be possible to make the Atlas type work on a SB, has anyone given this any thought? Matt (4627)
Matt, Thanks for the WEB site I haven't been there since I got my 9A and I had forgotten about it. Maybe I am missing something. If you go back to the site the very first item on their list of products is a T-slot crosslide for South Bend 9 and 10K. I don't know what you have so I apologize if this is not new information to you. Jim (4641)
No problem, I go and drool there quite often. I know they have a special Crosslide that uses the SB compound, but I was thinking it would be handy to have one that had T-slots all the way across, not to say that the SB t-slotted crosslide wouldn't be nice to have also. Matt (4643)
Matt, Your question about using the other cross-slide got me thinking that one of those would be more useful to me than the one expressly for the 9" SB. I'd rather have a boring table than some place to mount an inverted cutoff tool. Looking at the dimensions, it looks like it would work great. Good call! The other thing I was thinking of was just making a fixed one (no leadscrew nut) out of aluminum for the occasional line-boring operation. Paul R. (4644)
I have a t-slot cross slide that I am interested to part with. I bought it finished machined from MLA about 18 months ago. At this time I am most interested in trading for some tooling for my SB 9A I am looking for a steady rest and a follow rest for my lathe, or what have you. I have placed a couple of pics in an album called t-slot cross slide ( the only ones I have right now) The first one shows the MLA cross slide next to its replacement, which is designed to fit a taper attachment. The second pic shows the new cross slide mounted on the lathe, before I finished all the machine work. I will post some more information on this project if there is any interest, when it is complete. Pete (4666)
G'day All, There was a recent thread on T-slot cross slides. I found this one available at the UK Lathe site: http://www.lathes.co.uk/salespic/boxfordtslide/ Bill (4781)
Funny you should mention that bill, cause I just tried to fit that exact cross slide on my heavy 10" lathe. Wouldn't fit, darn. I had a flyer about 5 years ago that had one of those for sale as a rough casting. I have considered machining one for myself, way down on the long list. Joe V. (4786)
I have just posted a picture of the T-slot cross slide that I have made for my SB 9A. ( in the photo section under t-slot cross slide) It is designed to accommodate the original SB taper attachment. Please excuse the paint job, I plan to refinish my lathe in the near future and I didn't want to waste the time on it now. ( now if I can only figure out what the correct color is?) Pete (4789)
Beautiful Job Pete, where did you get the iron? I would love to make one of those for my 10". Do you have any drawings? Did you use a tapered Gib or set screw type straight gib? Joe V. (4791)
Light 10 crosslide screw
I have been slowly cleaning the absolutely filthy 10K accidentally acquired at auction (went to get Hardinge HLV-H, only came home with SB light 10 :^)). Disassembling, parts wash, touch up fitting, reassembly, re-alignment. Last night got to run it for the first time, though taper attachment is still in the parts wash sink. It was obvious at auction the crosslide screw had a good bit of wear. Disassembly showed the screw and nut may last a few more years, but they are sloppy (to say the least) and fading fast. While the lathe is back together, I would like to make a new set. I _know_ it was irresponsible, but was in such a hurry to try lathe out, I did not mic it while apart. Also, could not get 3 ball handle off, and so could not check dimensions and shoulders beyond screw area. I did get the handle off the compound, so understand how it works, but the crosslide handle was a bit more stubborn, and I decided to wait until I could rebuild that component. So the question is: Is there a site or archive to download prints or dimensions for a SB 10K, model A gearbox, crosslide screw. Don't know if it matters, but this one has the taper attachment style slide. Also, does anyone know what material it was made of, and what would be a better material? smt (4873)
There is a difference in the nut for the taper models. What you might think about is sleeving in a new section of ACME thread to repair your crosslide lead screw. I can't remember the cost off hand. I think a complete crosslide lead screw will sell for about $65 to $100 depending on condition. I think Plaza sells reconditioned ones for about $100 and the nut for about $35. He also sells a section of acme thread for I think $30. You might check the prices at McMaster-Carr etc. for lead screw material. Tom (4874)
I actually just read about how I guy bought nuts and threaded rod and did this exact repair and it worked great according to him! http://pages.cthome.net/errol.groff/south_bend_cross_slide_screw_repair.htm Tom (4875)
Thanks for the information. Since the rest of the screw (all but the threads) seems unworn, your suggestions to sleeve on only that section sounds brilliant. I use Acme rod from MSC for other applications, had forgotten they also have the precision stuff, almost dirt cheap, for leadscrew apps. Looks like a 3ft section of alloy steel acme 1/2-10 LH is 21.30, and the bronze nut is 19.09. Best thing is the work (turn down section of acme to insert into interference fit bore in remaining section of old cross slide screw) can all be done in the split bed lathe with the SB apart. This really makes the job look simple. Stephen (4900)
Heavy 10 cross slide
The cross slide on my well used heavy 10 has a lot of slop. I have tried the gib but it only stops the movement at the extreme out position. Is my problem in the cross slide nut or is there a way to take this out? (5566)
Not clear on your problem. If you can grab the cross slide and shove it forward or yank it back a "substantial" amount, it is probably the nut and screw. Check also that the collar on the micrometer stem that acts as a thrust washer is adjusted to remove slop at the screw stem. Check also that the screw that retains the leadscrew nut is snug. Especially if you have a taper attachment and take the screw in and out periodically. As far as mitigation therapy, the screw and nut can be pretty far gone before you "have" to do anything about it. Just always take your backlash out going the proper direction, which is proper procedure anyway. If you are saying you can shake the cross slide sideways, unless the gibs are so tight you can't practically move it, then you will have to rescrape the dovetail ways. smt (5568)
The type of slop you are talking about is not clear but sounds like you definitely need to shim the gib if you can bottom it out. A long .010" shim between the gib and cross slide (not against the wear surface obviously) will allow you to snug the gib which should fix most side to side slop. A piece of discarded feeler gage is good for this. Try to match the length of the shim to the length of the gib. Also completely remove the gib and cross slide and thoroughly clean the ways since there is likely much swarf in there causing problems. The wear will probably be uneven so you have to compromise the gib tightness to get your full range of travel. Backlash caused by worn nut and screw is not really serious unless the screw is moving, or screw is severely worn which could cause lead error. Joe V. (5573)
My message was not clear and I apologize. Let me try to describe the problem. When I grab my cross slide I can make it move back and forth about 1/4 inch. I tried cranking it forward and it holds but if I push it it will move forward and the reverse is true when I crank it back. I 'm not positive what backlash is but I have an idea. This is like the gib is not holding. I have a taper attachment and there appears to be a few thousandths play between the end of the feed screw and the end of the taper attachment sleeve but not enough to cause this much movement. If it is the gib is there a fix that doesn't mean making another gib? Strom (5578)
I'm still not sure in what direction the play is. If you can move the cross slide toward or away from the headstock by any detectable amount (by just pushing and pulling on it or on the compound), you have a gib issue. The gibs just assure that the cross slide moves exactly perpendicular to the turning axis, with little or no play. If the play is crosswise to the turning axis, that is in the direction the cross slide is supposed to move, I don't see how it can be the gibs. It could be the nut, either due to wear or it's mounting. It could be the bearing where the cross feed lead screw is anchored to the cross feed. If things are moving 1/4" I expect you can look at things move with the sheet metal chip guard out of the way and see where the play is. If you can see what moves perhaps I can look at the same place on my heavy 10 and tell you what is supposed to sit still and what is supposed to move. Frank (5581)
It's not the gibs. It's the leadscrew/nut combination. As mentioned previously, check that your collar is adjusted to remove any play where the stem comes through the casting for the mic dial and handle. Also check that the screw that holds the leadscrew nut in place is tight. After that, all the slop is from a worn leadscrew and nut assembly. Mine (light 10) is not quite as bad as you describe. But I rebuild machinery from time to time, including precision re-scraping, so it bothered me enough to consider making new parts. (easy to do, we all have lathes, don't we?) I got several pieces of good advice from this list, including a link from Tom Jelly that describes a pretty easy straight forward fix using prefab generic precision lead screw/nut assemblies from the MSC Industrial catalog. Do a search of message #4875, and click on the link Tom included for me. I found the parts for my 10K (actually enough for several lead screws, though only one nut) for under $50; and I have little doubt they are probably better quality than SB stock. In the event, I have been living with the slop. It is not a problem, if you have the gib adequately (_NOT_ overly) tight, and always use good practice in which way you end the leadscrew motion for the work. Make all fine adjustments using the compound. I do intend to rebuild the nut and screw as per the article "eventually", but can't afford the down time right now. The design of SB or most simple lathe nuts will not permit you to ever eliminate all slop, this is the reason for good practice in the direction you make you final move when setting the cross slide. Always to take up the slack. A brand new assembly and well adjusted collar may get you to within a few thousandths total backlash, but it will still be there, and will bite you at sometime if your habits are not good. smt (5582)
Strom This sounds exactly the same as the problem I had with my Heavy 10 which was due to some dingbat removing one of the thrust bearings from the leadscrew mount in the taper turning attachment. Assuming that your lathe is like mine, with the telescopic leadscrew, the cross slide feedscrew is actually fixed in the taper attachment not to the graduated collar handwheel assembly as is normal on most small lathes. The feedscrew has a plain extension at the rear which passes through the hollow rod onto which the upper binding lever clamps the taper turning unit when taper turning. There is a thrust bearing at each end of this rod with a nut and washer on the back end of the feedscrew to lock everything up tight. I presume things should be shimmed for nominal zero play. The handle spindle just turns the feedscrew via sliding collar or splines (I've not looked) so when taper turning the feedscrew can slide up and down on the handle spindle. I solved my problem by making a solid spacer bearing exactly the right thickness (near enough 1/4") from Glacier dry bearing material which will do until I get the right part. The basic movements are fairly stiff so it takes a good shove to actually move the feedscrew in its mount so as to reveal the play due to a missing bearing. On mine you could do an accurate job of turning dural with normal feeds and cuts or a light feed, light cut job on mild steel just relying on the stiffness to hold things in place. It wasn't until everything went whahooie shape on a screw cutting job that I discovered the problem. Clive (5626)
Ball handle threads on cross slide
I removed the cross slide ball crank on my 10K as the handle was broken and I wanted to measure it to make or purchase a replacement. The parts list shows the handle as removable from the ball crank but I couldn't get it off on the machine. Anyway, the ball crank was stuck so I used a puller on it...I knew it was a bit Neanderthal but I was only going to use very little force on the puller. Anyway, I deformed the threads on the lead screw end that the ball handle nut threads onto. I have a couple questions: It appears that the threads are #12-24 is that correct? I'm worried my measuring may be off because the threads are deformed. The only small male thread I found in my "shop" was a #10-24 and that was a very loose fit in the ball handle nut. So I'm assuming the thread is a #12-24. I'm thinking of making a split thread forming die by splitting a piece of mild steel then drilling and tapping it on the split. I'll then assemble the split die from the rear portion of the damaged threads and thread it on from the undamaged rear side of the threads. My goal is not to cut new threads, but since they deformed that easy, to "form" them back to serviceable...does this sound good? (6566)
Been there, done that (doh!!) I recently had the experience if repairing the threads on my cross slide screw. ( please don't ask why!) I didn't have any 12/24 stuff so I cutoff the thread, drilled the end of the screw for 10/32 about 3/8 deep and loctited a 3/4 long set screw in. I them made a new retaining nut with the new thread. Worked good! As to your suggestion about the "repair" of the thread by backing off a split nut, I have done this successfully many times when the thread is slightly damaged. If you can obtain a high quality nut ( as opposed to a cheapo hardware store one), split it with a fine saw, gently smooth the cut line with a fine file and place both pieces on the good threads. Hold the split nut in either a 6 point socket or with vise grips, gently applied, and turn off the thread. you may have to do this several times. Pete (6567)
I'll keep your set screw method in mind in case I mangle the thing more trying to fix it! (6571)
SB 9 Cross Slide 7/16 X 10 Acme Nut Misery
I have a SB 9" Model 409AN Serial # 73878 and the cross slide has too much front to back backlash the gibs are fine with no left to right play. I took the compound apart and the screw looks good, the nut looks like cast iron, its not the color of bronze has a good 50 thousands slop. I have looked in @ 8 catalogs and the web for a 7/16 x 10 Acme tap, and can't find one. Does any body have a doable solution? (7006)
There's some files here on the group site pertaining to this...also check out http://pages.cthome.net/errol.groff/ and scroll down to "South Bend Cross Slide Repair". Errol had the same problem and an unwillingness to pay SBL [now LeBlond] prices for new parts. On the same topic, has anyone ever tried Loctite Form-A-Thread? I know the stuff was tough enough to hold the swingarm pivot in my old Harley's frame for a couple years of hard riding...but I don't know how it would stand up to the abrasion of constant movement. Could a tap be fabricated from a short length of acme rod? Could an Acme tooth cutter be ground from a tool blank, then used to fab a tap? (7007)
The adjusting nut on the compound my "mew" model A is missing and the threads are damaged. I emailed South Bend and other than offering to sell me the nut for $6 they weren't too helpful. Because the item is still marketed they refused to give out the specifications for the thread. From a quick measurement the thread looks to be 24 tpi. I think it is 60 degree but didn't look at it really close. The ID seems to fall between a #10 and a #12 screw thread. I haven't found any standard that matches this measurement. If SB would have been more helpful I would purchase the nut but I still have to repair the thread. I can probably repair the thread with a file. I'll look into the Form-A-Thread as I might be able to make a #12 nut work. Sound reasonable or should I just bite my tongue and order the part? John (7011)
There's a now-obsolete standard, not even in current machinery's Handbooks, under the old thread system, for 3/16-24...it's within a couple thousandths of a 12-24, and it's the old American [pre-UNC/UNF] 60-degree threadform. I have a couple taps for this thread if you need one. You aren't talking about the leadscrew then...what part ARE you talking about? The thread in the TOP of the leadscrew nut? or...? Yeah, I got the gearbox. Nice one too. I have another in not as nice shape, pretty worn but still transmits power, I'll let got for $125. Lurch (7015)
Lurch It is the nut that holds the handle on the feedscrew. It also adjusts the endplay. I think it is a little bigger than 3/16 (0.1875). A very quick measurement on the OD gave m 0.215". Could it be 7/32 (0.219") I didn't attempt to do a three wire measurement (not sure I know how). I need everything that you got from Mr. Ed. Leadscrew, outboard end leadscrew bearing, gear bracket mine even has the 42" bed!. I'm chasing a gearbox and leadscrew on ebay right now, unfortunately they are seperate items so I have to be careful about winning one and not the other, so I can't bid to high. I think the bids close in 4-5 days so I can let you know about your gearbox next week. I've never ran a lathe bigger than a Unimat DB200, so what could I expect from your worn gearbox? John (7017)
Email me offlist and we'll work something out as far as you 'hauling away that old greasy junk' and paying for the privilege of hauling it away chuckle need my parts washer for something other than storage and the little lady off my a$$... I have an extra compound or two as well...was going to use one for to build a milling attachment, but the other we can deal on. Per Machinery's Handbook the major diameter of a 12-24 is .2078-.2150. The minor diameter is .1710-.1810. There is also a 1/4-24 thread w/MINOR diameter of .205-.215, which although it sounds unusual, at least one tap for that bastard thread is in every decent Harley mechanic's toolbox. (7019)
I am at a slight loss here, I did not know that there was an adjustment screw? Clint (7024)
John, The nut doesn't adjust the endplay, you need to machine the bushing or the end of the feedscrew to adjust the end play. There was a note from SB on how to do it in the files section a while ago. I haven't looked to see if it's still there. I have an extra "A" leadscrew for a 42" lathe and right end support bracket if you or anyone else need it. Glen (7025)
Glen Does that mean that the nut is just tightened up tight? I'll go look for the instructions now. John (7026)
Are you talking about the slotted nut that holds the crank knob on the end of the leadscrew? (7027)
Clint I've been talking about the nut that retains the handle on the compound screw. I assumed that this could be used to adjust backlash. According to Glen R's post this is not the case and I will have to machine the end of the screw itself. I haven't found the SB instructions Glen mentioned so if someone could point me in the right direction, I'd be forever grateful. John
(7028)
Yes (7029)
[total backlash]=[play in leadscrew fit to leadscrew nut] + [endplay in leadscrew-to-bushing]. Slop in the screw-to-nut fit is just plain wear. Endplay slop in the leadscrew itself can be shimmed out. As to causes of the latter I would look at thrust bearing wear first. (7030)
This is what happens when I start to compose a message from work and get interrupted and someone else asks the question and it gets answered before I finish and hit 'send'. No wise-apple-ness intended. (7031)
I found the document I was talking about. It was actually related to end play in cross slide lead screws, but should be applicable to compounds as well. Check the attachment in this list posting: http://groups.yahoo.com/group/southbendlathe/message/1824 Shims would probably work, too. The slotted screw on the crank should be tight or else it keeps working itself loose. Glen (7032)
Last week I posted for source for 7/16 X 10 Acme treaded rod and tap. They were just not to be found. My Cross Slide had about 3/32" forward and back slop (not from ball crank). I had read about cutting off old thread and press fitting a piece of 3/8 X 10 Acme rod and modify a stock precision nut to fit. I inspected the old Acme rod and nut and found that the rod looked really good and the nut was worn. I thought if I could get a new nut, it would probably reduce the slop to usable condition. No nuts to be found - a few maybe promises but no nuts. I called LeBlond and a new nut was $40 + $7 for screw, they came in kit form only, the threaded rod was over $700. I ordered a nut, it came, it was a forged bronze piece with no 2 slides parallel, but the threaded hole and the mounting hole were in line and at right angles. I had to reduce by .060 the top surface to be inline with the cross slide. All works fine and I have no slop in any direction -- good as new (1937). LeBlond has a lot of parts, they are very high, again I say very high priced but they have them. I saw a picture of my nut in diagram, they said it wouldn't fit that mine should have a vertical post but it didn't, I took my chances and only had to take off .060 off the top. They also have a $10 order fee which has nothing to do with shipping. I guess they are a last resort parts source. (7163)
I think I posted that Plaza sells ACME Rod and the nuts. The nuts cost about $35. I think a foot section of ACME rod cost about the same. Still, I think others have ordered ACME Rod material and some nuts from McMaster-Carr. The ones from Plaza are a direct replacement. Still, 40 + shipping isn't too bad. Also, someone posted to check in the SB board files. I looked in there last week. There is a link or an article on this repair. Tom (7164)
T-slot cross slide?
Anyone on this list ever done the Metal Lathe [in Pennsylvania] casting for a t-slot cross slide? I have a lathe, with faceplate, 3-jaw and 4-jaw, and I am awaiting delivery on my Atlas horizontal mill...will I need a vertical mill to machine this casting without undue stress [to me, not the casting]? I'm thinking if I have a horizontal mill I can do the top and bottom, and with an angle plate and some parallels the sides and dovetails...I may have access to a vertical mill locally, but prefer to be self-sufficient if I can. On a related note, I saw a [supposedly OEM] "original SB milling table" on eBay for WAY too much money--looked to me like just a piece of surface-ground 1" flat stock about maybe 8" x 10" with a grid of tapped holes maybe 5/16-18 on about 1" centers, and a spigot on the bottom like on the bottom of the compound. First I ever heard of such a thing...and I wonder how well it would work? Anyone have any experience with this? Did SBL ever make such a thing? Lurch (8311)
I have done 2, one from MLA casting, and another from one I had poured myself (with a mod to fit a taper attachment) you will definitely need a mill, or a shaper with at least a 12" stroke. you may be able to do it on the Atlas with an angle plate. The MLA castings comes with the t-slots cast in so you could get away with not machining those. To my knowledge SB never made one, but it is standard on the Boxford lathes made in England and is interchangeable with the SB. They can be had used from G and M Tools www.gandmtools.co.uk for about 100ukp ( last time I checked) The cross slide can also be gotten from MLA, finished. I have one of those, that I am thinking of selling in the near future. I used it for about a year before I built my own. Pete (8312)
Also see t-slot cross slide in the photo section (8313)
Lurch, I finished my MLA SB9 T-slot crosslide last fall. A very interesting project. I started with a "well seasoned" preground casting from an estate sale. Vertical mill and more surface grinding finished it up. I did re-cut the T-slots. The dovetails were done with a dovetail cutter. The drawing is not always a perfect match to the casting, so beware. Andy has good stuff. RichD(8314)
Lurch, I did the MLA milling attachment. I did all of the machining on my lathe except the dovetails. The MLA instructions say to unscrew the bushing from the cross slide to get the extra 1/2 inch of travel needed to finish the cut in one go. I didn't feel too comfortable with that, so I did it on the Bridgeport at work. I still have the rough casting for the T-slot cross slide. When you start on yours we can compare notes. I also have a cobalt dovetail cutter and T-slot cutter. The dovetail cutter may need a little sharpening. Can anybody offer advice on this? Glen (8315)
Lurch, thanks for reminding me. I have an MLA-5 milling attachment kit if anyone is interested. It sells for $109.25 plus shipping from Metal lathe Accessories. http://www.statecollegecentral.com/metallathe/MLA-5.html  I'll sell it for $80 plus shipping. The castings are brand-new with no machining done to them. My cat knocked a half-empty glass of water onto the drawings, so the paper is a little wavy, but perfectly legible. I also have the S-5879A angle plate kit which sells for $23.75. I'll take $15 plus shipping for that if anyone is interested. http://www.statecollegecentral.com/metallathe/S-5879A.html  I'll sell both kits for $90 + shipping. Otherwise, I'll put them up on Ebay. Contact me off-list if interested. c (8318)
9" Cross Slide Slop Diagnosis Help
I have a war production 9" Model A with with .031 fore and aft slop in the cross slide. Fore and aft = grabbing the cross slide and rocking it back and forth. There is a gap at the cross slide dial of .023 If a .023 feeler gauge is put in this gap and the fore and aft slop is remeasured it it .008. I seem to remember replacing the cross slide nut several years ago. I have loaded pictures to this site below. There are 4-5 pictures under "Machine Tools". Doc (9945)
From your description it appears that the slop in in the hand crank/dial/screw assembly rather than the feed nut. I have an assembly drawing an it may be possible to remove this slot by tightening the slotted screw holding the crank However this seems to be pinned to the knob. I don't know how the pin is removed. Somebody who has done this may be able to tell you how. removing this would allow you to turn the screw 1/2 turn at a time to lower the slop. Not a total removable however. There do not appear to be shims for "fine: adjustment. My lathe has considerable more slop but its definitely in the feed nut.(9950)
Doc; There are several ways to deal with this. Please see the attached JPG before deciding on the best fix, once you understand the fitting of a new screw you can make a decision based on your particular machine. Simplest: Can you press the graduated collar against the bushing for the leadscrew and tighten it? Cheesy, but a way that works on some lathes depending on the location of the wear. Almost as simple: If option 1 doesn't work, turn a brass or bronze washer 0.023 thick to go between the graduated collar and the leadscrew bushing. If option 1 does work, stick the washer between the handcrank and the graduated collar. Still cheesy, but not as bad a kludge as option 1. The official South Bend recommended correction: Attached as a JPG. I thought this was in the files section of our group, but didn't see it there. NOTE: figure out just where the wear is before following this spec. You might only need to do steps 1 to 3, just step 4, or the whole deal. Step 5 is for new screws that don't have a pin slot, or cases where steps 1 through 4 took enough off enough metal to have made the pin slot too shallow. You can do this on the lathe being repaired, but it's a pain in the rear as you have to set the compound exactly perpendicular to the spindle axis and use the compound to face. You'll have to lock the cross slide at a workable position via the gibs as the screw, bushing, and collar are mounted in the chuck. Pad the chuck jaws with brass shimstock to avoid dinging the leadscrew threads. The remaining 8 thou isn't something I'd go through the flips and twists needed to get down to the 3 to 5 thou you set a new lathe up for. Stan (9955)
I'm still sort of processing but am I correct in my reading that the .023 is the problem, while the .008 is a tolerable amount of wear for an originally acceptable .005 measure ? Also I'm not sure I was completely clear: I replaced the cross feed nut but NOT the leadscrew. I have yet to figure out how the cross feed leadscrew and handle assembly disassembles. Doc (9959)
Yes, the .008" play is due to the fit between the feedscrew and nut. BTW, you may find that it's less than .008" at the far end of the screw. Disassembly of CF screw: The slotted nut at the crank end of the screw is RH thread. Make a notched driver. Remove the crank and dial. There are a few small parts to avoid dropping on the floor: a small pin which keys the crank to the shaft, and the pin and shoe to lock the dial. Nothing spring-loaded though. The screw support bushing is also RH thread. Most have a hole on the underside for a pin spanner. The group has commented that some bushings do not have the hole. Most people have been able to unscrew the bushing by clamping it using wood or leather pads to protect the bushing from the vise jaws or big vise-grips. (9972)
Doc; Short answer - Yup! Some ways to get the handcrank off are at the bottom of this post. Long answer: In almost all leadscrew setups, there is some free play required between the nut and the screw to allow smooth motion while not being so tight as to cause premature wear to the nut or screw. This is the minimal backlash for a particular combination. Ballscrews can have zero backlash, but they aren't appropriate for manual tools as they rely on stepper or servo holding torque to keep the table/cross slide/ whatever from creeping. The leadscrew itself has to have some endplay unless you have a setup using thrust bearings. This can be misinterpreted as backlash. Plenty of folks have snugged up split feed nuts on mill-drills trying to eliminate "backlash", when the real problem is endplay of the screw. If I'm not sure of just how the error is distributed, I mount a dial indicator to indicate the end of the leadscrew shaft and lock the gibs. Turn in firmly, and zero the collar and dial indicator. Turn out firmly. The graduated collar reads the total apparent backlash, the dial indicator tells how much of this is contributed by endplay. Total indicated backlash minus endplay equals actual screw/nut backlash. In your case, the quickie indication is that you have somewhere over 30 thou backlash. From your post and the pics on your site, it appears you have some fairly small amount (0.008") of backlash in the screw/nut, and a large (0.023") end play in the leadscrew. You can get endplay down to 1 thou or so using the approach outlined by South Bend. Once the endplay is fixed, you may find 8 thou backlash throughout the range of motion for the cross slide. If this is the case, you can live with it, replace the nut again (maybe you'll get a better fit, maybe not), or try one of the assorted methods folks have devised to take up a bit of the backlash. Most of these methods involve splitting the nut and compressing it, or making one part of the nut adjustable so you can rotate part of the nut to take up the backlash. A constant backlash almost always means a worn nut, oversized female threads, or an undersized leadscrew. Leadscrews just don't wear evenly over the entire range as they aren't used equally over their entire range. It's more likely that you will find a range from 8 thou to something smaller or larger over the range of motion. The smallest number will probably be with the cross slide far out or in past the center cutting point. This amount of backlash is pretty much the lowest you can get with the existing nut, and is set by the wear of the nut and fit of the nut to unworn screw, plus the small (1 thou or so) endplay, something you have to have or the leadscrew couldn't turn. Without modifying the nut or making a custom nut, this is it, the least backlash you can have on your machine. In some portion of the motion, you'll likely find a few thou more backlash. This is a combination of screw wear PLUS the basic backlash of your screw and nut combination. And of course the small but non zero endplay of the leadscrew. About the only way to handle a worn screw is to live with it, buy a new leadscrew from SB (very expensive, for the SB13 the cross slide leadscrew was quoted at around $1375), or buy precision acme left hand threaded rod from MSC. Turn down a stub on one end of a length of threaded rod, cut off the worn screw, and bore out the unthreaded portion of the existing leadscrew body to let you silver solder/pin/press fit/loctite a new length of screw to the existing leadscrew body. You'll have to hold the body of the leadscrew in a 4 jaw and dial it in zero-zero or use a collet, you really want the screw centered to within a tenth or so in the leadscrew body. It's a touchy job to do well. Plenty of folks have done it, it's just a first job of the day rather than just before bed bit of work. Yes, you can cut your own leadscrew, but the effort required and the likelihood of generating a screw with more error than the 9 thou per foot even the cheapest acme threaded rod is guaranteed to have worst case makes this something you only do out of desperation rather than choice. I think a 3 foot section of the correct threaded rod is only around $36 or so from MSC and you'll have enough for 2 or 3 sections. From all of this, you can appreciate why I wouldn't chase the 8 thou lash in the screw/nut, it just isn't excessive and fixing it takes a fair bit of time or a large bit of money. If you have a badly worn screw, such as the one on my old beater SB13 that ranges from 6 thou up to 40 thou then back down to around 8 thou of backlash , replacing the threaded portion of the leadscrew may make sense. I would if this was my main lathe, but on the rare occasion I need to dial in a really close cut, a dial indicator can be rigged up easily enough or the compound can be used for tool advance as it's leadscrew is in good shape. I'll do it one of these days, it just isn't a priority as this lathe is rarely used. To remove the nut that has the split screwdriver slots that secures the handwheel, you can grind a notch in the center of a large screwdriver and then grind the blade to fit. A nicer approach that is easy if you have access to a mill is to drill a hole (3/16 comes to mind, but it's been a while!) into one end of a piece of 1/2 inch drill rod, face it nicely, then use the mill to create a screwdriver blade with a nicely sized gap in the middle. I made mine with a hex on the far end so a socket on a small ratchet could be used to drive the tool. Others have pressed pins into a piece of aluminum or steel stock 1/8 inch thick and 3/4 inch wide, then ground flats to fit on the end of the pins. Just a pin spanner, but made for slots rather than a pair of holes. Like most things, there's any number of ways to get the little bugger off and back on without doing anything tacky like using a punch and hammer - a BAD idea, you'll bend the part of the leadscrew that sticks out past the mounting bushing. Once the nut is off, you'll find the handcrank is prevented from rotating by a small pin that is pressed into a hole drilled half in the handcrank, half in the outboard end of the leadscrew. Try not to loose this pin, seems it was some odd 64th size bit of stuff on at least one of my lathes. I had the right size in stock, but unless you stock a full range of smaller sized drill rod it could be frustrating. I guess you could always open up the hole slightly and use some size already on hand. Stan (9993)
When I first got my SB lathe I trawled the net endlessly for information about it, and SB lathes in general. I came across one well illustrated site that showed an operation on a leadscrew (main leadscrew) done in much the same way that Stan describes here. If I can re-locate it, I'll post a link. Len (9999)
Needing to remove my crosslide hand cranks last evening (I'm about to fit the larger direct reading dials) I duly made a notched driver and removed one nut easily. The other, that already looked a bit "animalised" would not shift at all, and curiously, looked deeper set within the boss of the crank handle. On close inspection, I saw that the end of the spindle had been centre punched quite hard, presumably as a means of ensuring the nut didn't come off. I tried drilling that out, tiny bits at a time, but still could not move the blasted nut, even with the driver supported by my belly, and a stillson wrench on the screwdriver blade, so I drilled the damn thing out until I could remove the nut and crank. It looks as though the threaded end had already been broken off, hence the machined inset into the crank handle to allow pick up on what remained.. What with the break and the small amount that I drilled out, I no longer had enough thread to be comfortable with. I locked the top slide in position, removed the leadscrew, chucked it and drilled a hole down into the end, which I tapped M4. I now have a mushroom headed machine screw holding the crank handle on, and although it is a Phillips cross head, looks virtually identical at a quick glance, to the original nut. Len (10057)
New Cross-Slide Threaded Rod
The threaded rod (and the bronze "nut") on my "new" 13" South Bend are worn to the point that the acme threads look like wide spaced UNC threads. What are the prospects for replacing this rod? Since the lathe has a taper attachment, there is an extension beyond the threads and "end flange". I don't know if this is all one piece or separates at the flange. If one were to undertake making a replacement, would drill rod be the right material? Would that be water hardening or oil hardening, and what would the hardening process be? What are the alternatives i.e., live with it, buy a new one, buy a used one. Mark (10355)
Mark- If all else fails, see me for a new one. Rose Marvin (10357)
Search the archives. I think this was discussed and written up in the files section. IIRC splicing in a piece of a