Lathe - Apron/Carriage

A/B Apron Gasket (Jun 3, 2001) Repair halfnuts (Jun 17, 2003)
SB Lathe Carriage gib adjustment? (Aug 1, 2001) Non-functioning clutch on 10k (Oct 26, 2003)
Apron kicks into gear for no apparent reason (Dec 12, 2001) Half nut repair (Nov 24, 2003)
Half nut restoration (Mar 22, 2002) 9" half nuts (Dec 8, 2003)
Unknown hole on end of SB9 apron (Apr 26, 2002) Half Nuts and saddle questions (Dec 14, 2003)
9A apron controls (Jun 25, 2002) SB 9A Apron questions (Jan 31, 2004)
Jumping Carriages (Aug 3, 2002) Question on heavy 10 Carriage (Feb 21, 2004)
Source of Bronze filings inside Model A/B Apron (Aug 24, 2002) Apron worm gear replacement (Mar 27, 2004)
Clutch in a 9A apron? (Nov 5, 2002) Apron clutch construction (Apr 6, 2004)
Restoring Half Nuts with a bronze bushing (Nov 8, 2002) Half Nut Repair (Apr 15, 2004)
Sticky Clutch (Nov 25, 2002) Clasp nuts / Split nut SB 9" (May 4, 2004)
Key in Apron Falls Out! (Dec 29, 2002) Worn worm wheel SB 9" (May 5, 2004)
SB 9A clutch assembly (Mar 17, 2003) Fitting new half nuts (Nov 2, 2004)
Halfnut slack (Mar 30, 2003) Slop in apron handwheel (Jan 27, 2005)
9" apron question (May 9, 2003) Worm and wheel drive for 9" (Feb 12, 2005)
A/B Apron Gasket
In the process of installing the carriage lock, I took off the apron and saddle. Wow what a mess! In the years that I have had the lathe, I never took it apart more than I had to. I think that the previous owner used it for some wood turning: gunked up/oil soaked sawdust everywhere in the apron, dried and hard. the oil holes in the half nuts were plugged. I have taken off the half nuts and sheet metal cover to the worm drive and friction clutch to get better access to clean it in there. I put the whole thing in the parts washer and flooded it for a while to soften the gunk. Bronze tooth brush and toothpicks are handy for cleaning... I am missing the gasket between the sheet metal cover and apron casting. From the parts breakdown, it forms a well for the oil bath on the gear train Can anyone describe it? Is it paper, felt or cork? I almost hate to find out what SBL wants for the gasket. I am tempted to make my own. I have some 0.030 EPDM rubber and some 0.030 cork gasket in sheet form. Is it advisable to use either of these as a gasket in there? (775)
I went thru the same with mine, I just made a new gasket from light gasket paper, worked good. I agree on the prices from SB TOO HIGH! But available. Bob (776)
Yup, it is a paper gasket. About .010" thick but you can use whatever thickness gasket material you have on hand. Thickness isn't critical on that cover. Just need to keep the oil in. Webb (780)
And remember, it's not under pressure, so it should be straightforward. In a pinch, I used form-a-gasket. Next time I have the apron apart, I'll probably make a nicer one, though. Paul R. (783)
SB Lathe Carriage gib adjustment?
I can feel motion, maybe a couple of thousandths, when I lift the apron side of my 1969 heavy 10 carriage. As far as I know the only takeup is the two gib screws under the opposite side of the carriage. Those do well for the off side, and there's no lost movement there with the carriage moving smoothly and easily. Do I live with this slop? The ways are good, even excellent--this occurs at any carriage position equally. Would it be OK to remove the apron and hone it's mounting surface to bring it up and get rid of the play, or is this more or less normal? (1242)
This is normal with any lathe. Normal cutting force is down on the apron side, therefore no need for gib control. If you wish to tighten this side up (like when using a tool bit upside down) snug up your carriage lock a bit. (1245)
Apron kicks into gear for no apparent reason
I have this old 1947 SBL 9"x48" Model A lathe. For months the rig will run like a Swiss watch and then all of a sudden like last night, I'm doing the finishing touches on a nice little brass race and all of a sudden the apron kicks into gear for no apparent reason. The clutch is COMPLETELY out ( turned fully anti clockwise and then I always back it back a hair). I then run the carriage back and forth a few times and it is OK until for some reason a couple of months later it will do it again. Lots of good lubricant, everything nice and clean. And it always seems to happen when it can just wreck a sweet little job like last night. I'd swear a invisible hand is making it move. Does anyone else ever heard of this or know what the problem could be? (2397)
As a relatively uninformed guess, perhaps a chip is getting into the clutch and creating enough friction to transmit torque for a while? Or perhaps some sort of clutch material is flaking off? I tend to keep the leadscrew off when I'm not using it, as the straight tooth gears make a real racket at higher spindle speeds. Of course, in between cuts it's hardly worth moving the reversing lever to neutral, so I can see how unexpected clutch engagement would cause problems now and then. Chris (2400)
I'll take your advise Chris and take the apron apart and see if there is a chip or a piece of whatever in there. Thanks for the info. I'll post my findings when the job is done for future (spook hunters). (2403)
I always wondered about the SB clutch. Is there any advantage to a friction device, rather than a dog clutch? Would it not be possible for a friction clutch to engage itself, if there was slight drag on it? (2408)
This applies to my 1929 SB13 apron, can't promise that it applies to other SB tapered clutch drive aprons. My SB9 is a model C, so I can't check on that. This model uses a knob you rotate to tighten a cone clutch assembly. The tapered male part of the clutch revolves with the shaft it is mounted on. There is a selector lever for power cross or longitudinal feed. For the clutch to self actuate on this lathe, you have to have the lever in one of the power feed positions, the lead screw has to be revolving, and you have to get a sufficient piece of crud into the tapered surfaces. Being a taper, when fully disengaged, the spacing between the tapered surfaces is almost an 1/8 inch. While possible, it seems unlikely that a 1/8 inch chip would get into this part of the apron, bounce at the just right angle, and produce the needed drag to actually engage the taper. Possible, but not something that keeps me up at night :-) Looking at the PDF Army manual, it looks like the 9 uses a pair of shoes, engaged by wedges when the lever is flipped. I notice there is a spring that appears from the drawing to hold the wedges clear. If this spring weakens or breaks I imagine you could get some interesting clutch behavior. Stan (2411)
I thought the idea of a friction clutch for the power feed was that it could slip when the saddle, under power feed, hits an obstruction. This means one could use a indexing stop to machine a series of items to the same position. A dog clutch would not allow this. David (2416)
The handbook from Boxford (UK Southbend copy) shows a set of six adjustable length stop rods mounted on a rotatable 'turret' which is fixed to the saddle. David (2420)
Well, perhaps the dog clutch approach is not quite so cut and dried. My 11" Hardinge HLV-H uses a pair of single tooth dog clutches in one of the slickest threading processes I've ever seen on a manual lathe - one clutch for each direction. You can set the end point within .001" and it will stop there *every* time as you retrace the thread with increases in thread depth. After years of threading at painfully slow speeds on the Heavy 10 so I could manually release the half nuts in time at the end of each cut, it's a rush to do it at 500 RPM or more and be sure the lathe will stop at the right place. The method requires a small "landing zone" at the end of the thread - you can't thread right up to a shoulder because the spindle keeps turning when the tool gets to the stop. The half nuts are never released during the entire threading process. They modestly recommend keeping the spindle speed below 1,000 RPM. Mike (2431)
You can use such gadgets by manually winding the saddle to the stop, which is what I assumed had to be done. Now I'm wondering: would it hurt the lathe to use it as you suggest ?(2436)
Half nut restoration
I built the fixture described in HSM for restoring half nuts. I have bored out the old threads and now I am thinking of silver soldering a bronze sleeve in the resulting hole to be threaded 3/4 " x 8 Acme. I have never silver soldered cast iron. I am a bit leery of brazing bronze as the melting points may be incompatible. Glen (3701)
Soldering Brazing I don't know what is going on here. Glen (3703)
Glen, I posted on this around January. I had mine built up with WELCO 14 BARE nickel silver alloy. I just got my 9" running last week and the halfnuts I rebuilt with this procedure are as good as a new set if not better. Here are a few added thoughts in addition to the article. 1. I did all my work on a Bridgeport mill. This procedure can be done on the lathe as in the article but the mill setup is sturdier 2. I bored the original threads out to .85 dia. I reasoned this would leave .05 of alloy to act as a "base" for the threads. 3. The halfnuts appear to be made from a single casting and split down the middle with a 1/8 cutter after all factory machinery is complete. When I sized and cleaned up the silver solder I left the center portions heavy so there would be .005 or less between the two nuts when in the fixture. (In the fixture the nuts are in the engaged position on the lathe.) In hindsight I believe this step was the basis for my threads coming out as good as they did. I'll explain. I purchased a new tandem acme tap for this project and during tapping I had to add clamps over the threaded portion of the nuts as the casting would flex away from the tap. I tapped about 1/4 turn and backed out. I did this while advancing 1/8 to 1/4 turn each time. By having a full diameter of metal around the tap I experienced none of the "breakout" that would have been felt with the 1/8" gap between the nuts. Also, you can purchase a single stage acme plug tap for about 1/3 the price of a tandem. Don't even try to do this with an acme plug tap. I think the nuts would break from the forces required to remove all the metal with the single thread former on the plug. I have spent the last year rebuilding my 9" and at some point in time I plan to post pictures in the files sections so the group can see my toys. In this was to be pictures of these nuts and the fixture. If you have any questions feel free to contact me. Ed (3705)
Glen: That's alright it happens to us all eventually. Randy (3707)
One of my students busted the gears on the lead screw's drive on wends. I forgot which lathe that was, but believe it is one of my Clausing? Can someone help with a source to by new/ used gears. These belong to the high school where I began teaching this year. Boy you can forget a lot when you haven't touched something in ten years! That's how long it's been since I ran a lathe at SIUC! Steve (3711)
Glen writes: I am a bit leery as the melting points may be incompatible. Use a low temperature silver solder such as EasyFlo or PhosCopper. Both melt and run far below the melting point of bronze. Some here will not use PhosCopper on boilers because of the sulfur products in coal fired locomotives, so don't burn coal on your lathe if you use PhosCopper ;-) John (3718)
John, One of my many other hobbies is jewelry making (let's call it investment casting here, it sounds more macho). I was intending to use some of the solder I use for soldering silver to silver. I have several different grades "hard, medium, easy, extra easy". They are intended to be used in multiple step fabrication processes where the next solder operation uses a lower temp solder than the last. This worked fine on the cross slide nuts I made, but that was soldering bronze to bronze. I have never tried it on cast iron. Glen (3731)
Ed, My thinking was along the same lines as yours. I bored out the old threads to about .830 and planned to silver solder a sleeve turned from a bronze casting sprue. The extra material would hold the two halves together during the threading operation. A hack saw and a broken rusty file would do to separate the two halves and clean up the saw kerf. I purchased a tandem Acme tap on E-bay a couple of months ago and I have been itchin to try it ever since. Glen (3747)
Ed, I had the same thought as you about leaving some room for thread adhesion, but I was also thinking that a sleeve soldered into the half nuts would solve the problem of the two halves wanting to separate. Glen (3761)
Glen, Sounds like a plan. By using a sleeve and then splitting after tapping you will probably not see the two half's flexing away from each other while tapping. Let us know how this method turns out. Ed (3762)
Unknown hole on end of SB9 apron
What is this hole for? I've got two SB9A's and both have this hole on the right side of the apron, below the thread dial stud. Its not threaded and its fairly deep. It doesn't show on any of the documentation I have. Anyone know why its there? I have a Trav-A-Dial I want to mount on the SB9 I'm keeping, and am interested in using this hole as part of the mounting. Don't want to do any irreversible modifications. Rick K. (4091)
Rick, I picked up a 9" model A HMD last Sunday. It was manufactured July 30th, 1946 and has the same hole. Due to the position of the threading dial I cannot see that anything can go in there. I would suggest you call South Bend and ask for Ralph, who works in parts. Everyone knows him since he has been there for 40 years. If he doesn't know what the hole is for then no one does. Fred (4098)
Rick: I looked at my SB9C and I do not have that hole, so maybe it has to do with the more complex carriage necessary for the power cross feed, perhaps an access hole of some sort. I see you have two SB9A's, When you put up an SB9A for sale recently, I thought that maybe you had found the SB9A qualities to have been exaggerated and you were returning to your Atlas. From your picture of the carriage, it looks like you found a newer one with original factory paint, looks nice, what I can see of it. Rich (4100)
Very observant. Yes, newer, nicer, better, lots of candy. Plus a very nice cabinet. No, the SB9A attributes have not been overstated. The Atlas was/is just taking up room in the shop and in the way. I was presented with an opportunity to upgrade in SB9A features, etc and just couldn't pass it up. Bought new by a school in '56, bought by a retired machinist in mid 60s, cared for very well since. Family joke was how well oiled it and everything in his shop was. Photo attached. Rick (4107)
Rick, wish I could help on the Mystery Apron Hole. I have a 1937 "C" Model that my Grandfather bought new in 1937, but it doesn't have it. I've had it since 1964. Up until a month ago, I didn't know what the vertical hole on the Tailstock was really for. I had always used it to keep the key in for the Tailstock Chuck. I see you do the same thing. Now I'm looking for an original "Dauber". Benny (4108)
Rick: Very Nice, I would have been tempted also. Glad to know you are still enjoying the SB's. Its amazing how many SB's are out there, they must have made a lot of them. Rich(4109)
What a Beauty!! I nominate this lathe for the monthly poster machine!! The paint is also a very attractive color, is it original? If not could you tell me what it is? Pete (4110)
I never used the hole at all until this one entered my shop. It was in the dauber hole when I looked at it and I've started doing it. At least I know where it is now. Might have to add such a hole to my 7x12. Rick K. (4113)
Just sold the first one, the one you sent me the documents for. Made a copy for him, the beat goes on. Now just the Atlas 10F to sell and I have my shop space back. The candy that came with this one is way cool. Now that the one is sold, I'll take down photos of it and post more photos of this one, on my web site. Rick K. (4114)
Rick, I believe this hole is use when installing or removing the interlock pin that locks out the power feed lever when the threading lever is engaged. The power feed lever must (if the interlock is working properly) be in the center or neutral position in order for the threading lever to be engaged. I had an apron where this pin was too short and permitted the power feeds to be engaged at the same time the threading half nuts could be engaged. Fortunately, I corrected this before any accidents. Ed (4117)
Interesting. So, will it be possible for me to use a 1/4 or 1/2 of this hole for a locating stud for mounting a Trav-a-dial to the end of the apron without interfering with anything? Seems deep enough. Threading dial would get mounted on the outboard side. Rick (4119)
Guess I didn't finish my thought on using the hole for your purpose. I don't see any problem using the hole to mount the travel dial as long as it can be removed and the hole cleasrs in case you have to access the pin. Same type of mount as the thread dial maybe? Ed (4127)
9A apron controls
I've had my SBL 9" A for a few weeks and have been cleaning and trying to figure how to take things apart and attempting to determine what needs attention and what kind of shape the thing is in. Since the only reference I have is the old book 'How to Run a Lathe' that the owner I got it from still had, I assume this will not be a dumb question. In the South Bend book mentioned the apron controls have two levers and a clutch knob. In the book the carriage and cross feed lever has three positions. One for carriage movement and one for cross-slide movement and one for neutral. Mine has four. Two down drive the crosslide and one up drives the carriage and the fourth one which is the second up I cannot engage. There does not seem to be a neutral and I am hesitant to try threading until I am more sure of what I am doing. Jim (4738)
Jim, The hole at "twelve-o'clock" is an oil hole and you can't get the lever to it. At "one-o'clock" is the long-feed. At "two-o'clock is neutral -- allowing the split-nut to be engaged for threading. Finally the "three-o'clock" position is for power cross-feed. Paul R. (4739)
Paul, after further examination with your information I now notice that the 12 o'clock hole is smaller than the other three and the 2 o'clock as you put is in fact neutral. It still doesn't look like any of the other pictures I have seen but you are correct. I surmise from the serial number 145442 and the tag that confirms this lathe meets War Board standards that it was made during WWII. Imagine that. Older than me by not a whole lot and still turning metal. I really don't have a crying need for this machine but it's like owning a piece of history. I am going to do my best to restore it to somewhere near new and leave a legacy to one of my grandchildren if any of them appreciates it. I guess like other people in this group I am a tool freak, always have been. My first question is normally "How did they do that?". Which invariably leads directly to what tools did they have? How did they build those battleships with huge guns. How did they make a lathe in 1900 that could turn and bore a 14" rifled barrel? I seem to have digressed. Jim (4741)
I can't speak for the turn and bore of the barrel, but I know the rifling was an insert sleeve. During Viet Nam the Navy dusted off the New Jersey and the Missouri to use as gun platforms. Both needed to be re-sleeved and there was no shipfitter or machinist mate left in the Navy who knew how to do it. They found a retired master chief who hired on as a consultant to do the job and document it for posterity. Flash (4746)
Jumping Carriages
Folks Vertical movement of the carriage under cutting forces can be due to lathe assembly or set-up errors. The minions of SMAMAMT (Society for MalAlignment and MisAssembly of Machine Tools) are ever active. Frequently their efforts can only be uncovered by the sort of full check out which is understandably unattractive in the excitement of installing a new lathe especially when preliminary checks and first cuts suggest that all is well. My recently obtained heavy 10 did a couple of beautiful jobs on dural but turned its nose up at mild steel. Close inspection showed that all the headstock bearing shims had been removed and the rear thrust bearing for the crosslide leadscrew was missing! I would suggest that anyone suffering the same sort of problems as Mario makes a careful check of the headstock bearing adjustments. I have always found that accurate setting is much more important when trying to get a well finished bore than when turning outside diameters. It is also worth checking that the carriage is riding properly and snugly along both sides of the guiding vee. Its quite easy for a determined meddler to misalign the leadscrew so it either takes some of the weight of the carriage or is trying to pull it down. Little bits of gunge, wiper felt or even (please no) swarf can also get caught underneath which does not help. If its been run with the back gib loose an oil bound dust/gunge layer can build up which leaves things springy when the back gib is tightened down as it should be. (I know a man who spent two years nursing good results out of a 9" model C with the last problem! The comments after a couple of hours worth of stripping, clean up and reassembly fixed the problem were said to be "educational".) Clive (5558)
Source of Bronze filings inside Model A/B Apron
I bought a Model A/B apron for my model C. On disassembly and cleaning I found a ton of bronze filings but have not been able to determine their source. The gears and half nuts seem fine and everything functions properly. John (5967)
I'd have to guess that the previous owner did a lot of bronze turning, there isn't much bronze to be found in most lathes. Stan (5968)
Stan, I didn't find any bronze parts inside the apron and was hoping the filings were from turning, but the particles didn't look like swarf, rather more like fine particles from a worn out component. Anyway, I have to locate the appropriate screws to complete the upgrade. There were several on Ebay when I wasn't looking for them. It happens. John (5970)
Clutch in a 9A apron?
Please excuse the ignorance, but I am not aware of a clutch in the carriage of my 9A. I thought the only entities engaged when feed was actuated were the half-nuts, engaged by flipping the lever. Please enlighten me as to the location of this clutch. Bilal(6997)
The star knob, bottom dead center. Clockwise to engage, counterclockwise to disengage...and the lever immediately above it chooses power long feed, power cross feed or neutral. There's an interlock so you can't engage both kinds of drive at the same time. There's an excellent series on rebuilding an "A" apron with lots of pics of how it works at www.steammachine.com/hercus/ (6999)
Folks, I wonder if the 9 that I have is a model A or not; for the following reason: I don't have either the star knob for the clutch or the other three-position lever shown on the Hercus' carriage. I am 99 percent certain I have a model A, though. All I have is the lever for engaging the half-nuts...other than that, there is nothing on the carriage. Is this a model A carriage at all or not? The bill of sale dated from 1980 identifies this as a model A. Bilal (7056)
Bilal, Does it have a double tumbler gearbox or a stack of change gears to vary the feed rate? Glen (7057)
Look at E-Bay items 1784542127 (A Model) and 1785319432 (C Model). These should show you what you want to know. Maybe someone swapped out the parts. Does your lead screw have a keyway slot along it? Tom (7058)
Glen, I have BOTH a double tumbler gearbox AND a stack of change gears...to make the matter even more confusing. Any suggestions? Bilal(7062)
Bilal, It sounds like you have a Frankenlathe. If you want to convert it to a "full" "A" model, it shouldn't be too difficult. The hardest part is the gearbox/leadscrew which you already have. Your leadscrew does have a keyway milled down the whole length doesn't it? If this is the case, all you will need to do is obtain an apron from an "A" model and install it. There are 2 or three screws holding the apron to the saddle plus the carriage stop bolt and it's "brake shoe". remove the right side leadsrew support (have a friend support the lead screw while you are doing this) slide off the old apron and on with the new. You need to determine if your saddle has an opening in the bottom for the new apron worm gear to engage the gear on the cross slide lead screw. My model "C" Frankenlathe had a model "A" saddle, so this was not a problem for me. You will be very pleased with the power cross feed feature. The clutch feature is also useful when turning to a shoulder. I am always a bit tense when using the halfnuts for normal turning. There is no "give" in the system unless the belt slips. I see model "A" aprons on eBay from time to time in the $100 to $125 range. I relined a set of half nuts before I obtained an "A" apron. The "new" apron half nuts were tighter than the ones I relined. Since the half nuts are only used for threading, they see much less wear. Glen (7065)
Did you look at the E-Bay items I listed? If not then also look at : (Damn thing won't paste stuff where I want to.) Could have someone changed some parts on your lathe. Does you lead screw have a slot or keyway long its length? Tom (7067)
Bilal If it does not have the 3 position lever and the clutch knob, it is a Model C Carriage/apron. Does the lathe have a QC box? Clint (7068)
Bilal Is the QC gear box mounted on the lathe or is it separate? Clint (7070)
Glen, Tom and Clint, I most assuredly have a "Frankenlathe." The serial number is 49584-NAP-10, which identifies it as the 49,584th 9" Model A built. It just has a Model C carriage and a set of Model C change gears. Maybe the previous owner had a Model C parts lathe sitting around, and he decided to swap the carriage for some unknown reason. Tom, I did look at the eBay items you mentioned and by seeing them, as well as the link you provided, I decided I DEFINITELY did not have a Model A carriage. Thanks. Clint, as would be on a Model A, the gearbox is attached to the lathe, ie: appears to be integral. Bilal (7076)
Bilal You will be able to find a Carriage/apron for it but you will need to check the saddle and make sure it has the gear for the power cross feed. That is all you are missing at this time is power cross feed capabilities. Just to bad you did not get the carriage in the pile of parts, but that's the way it goes. Be thankful you have what you do have. Clint (7077)
Clint, Is that what the three-position lever above the star knob on an 'A' carriage is for? The power cross-feed? Bilal (7079)
Restoring Half Nuts with a bronze bushing
Not wanting to wait for Brett to figure out how to get into the group, I've uploaded his description and photos of how he restored badly worn SB9 Model A half nuts using a bronze sleeve. A short description file and two photos have been uploaded to the FILES area. http://groups.yahoo.com/group/southbendlathe/files/RestoredHalfNuts/ Rick K. (7061)
That is a beautiful and innovative way to handle the problem. Will have to file that into the back of my brain for a future project that I have. I never would have thought about doing that way. My congratulations. (7074)
What an innovative way to restore the half-nuts. No special welding or fixturing equipment needed. I'll be curious to see how the repair works over the long haul. Many thanks to Brett for the technique and Rick for bringing it to us. Brett should have no difficulty to get into the group. Paul R. (7083)
Sticky Clutch
My new to me 13x40 Model CL145C. has a sticky clutch, when disengaging the crossfeed or carriage feed it will sometimes stick, more with the cross feed than the carriage feed. It seems to be adjusted properly, as it engages fine and at the proper angle according to the book. This machine has been sitting idle for some time now, and I am thinking possibly I need to flush the old sticky oil on the disc plates. or is this the nature of the beast? I have previously owned a Logan, and an Atlas. however this is my first South Bend. Thanks Dee (7547)
A South Bend Maintenance page says-- To remedy a sticky clutch. The cause of a sticky clutch can usually be traced to dirty oil, improper oil, or edge of clutch disks are burred. To remedy. follow the steps outlined below. 1. Drain apron oil from reservoir and fill with kerosene. 2. Operate the lathe for a day or two and drain kerosene. 3.Flush with kerosene until clean. 4. Refill with South Bend CE1600 or equal. 5 If clutch remains sticky it is necessary to remove clutch assy to examine the discs. There are 15 more steps on how to do No. 5 on this page. Walt (7549)
I went out and drained the oil pretty thick stuff! added kerosene and Wa La just like you said after cycling it back and forth a few times it already was better! after about a 1/2 hour use it does not stick at all. I am going to leave it in there for a day, and refill with the proper oil. Dee (7551)
I am interested in your post because you appear to have a valuable manual I hadn't heard of. Would you tell us what publication your maintenance info on the apron came from, and if you know about it's availability. Thanks to the wisdom dispensed on this site I have a number of small publications for parts maintenance adjustment for my South Bend Lathe. I would love to add to it to get smarter about restoring/maintaining my lathe. Mike (7555)
Mike, when I bought an SB lathe at a High School auction years ago that sold out everything, the school guy there said to take any of their manuals related to the machine I bought. I picked up a large loose leaf manual that appeared to have all the data on a lot of SB lathes. Most of it is the regular parts lists, but mixed in under maintenance are a number of them such as the Sticky Clutch, procedure for converting from star wheel to lever on the Apron, and changes of installing large feed dials, etc. Since these are SB publications, Rose at LeBlond may know of them. I may not have all of them. I am not sure of the copywrite laws or I could copy what I have. Walt (7558)
The method on clutch cleaning is in the South Bend parts manual. It's a little over a hundred pages. I got a copy on CD. You should also get a copy of "How to Run a Lathe" from 1942, and a complete copy of "South Bend Lathe Bulletins". I got a copy of all these bound in one book. There are generally multiple copies of all these on eBay being offered by several different vendors. Just go to the Machinery section and look under lathes. Do a search on South Bend. Most are available via Buy it Now so you don't have to fool with bidding. They generally run about $12 to $17. (7574)
Dee I just uploaded a PDF file in the "techinfo" file section. It is a scan of the "How to Remedy a Sticky Clutch" page from the SB parts manual. Hopefully this will help. FYI, I've scanned all but a couple pages of the entire parts list/manual and will be soon providing a link to the PDF file. Jeff (7596)
Key in Apron Falls Out!
The 10L I'm working on came without the keystock that connects the leadscrew and the (don't know the name) gear in the apron. Without this, I obviously don't have power crossfeed and traverse. What is supposed to keep this in? Is it interference fit into the slot in the (don't know the name) gear that goes around the leadscrew? Wallace (8335)
One end of the key has a little baby dowel pin p/n 160X19 that goes through the key, through the wall of the wormgear, and through the nut that threads on the end of the wormgear. There's a good explanation of the apron disassembly/reassembly with lots of good photos at  www.steammachine.com/hercus Lurch (8341)
Wallace, On my 9 inch lathes there is a small pin that goes through the worm gear ( the one that is keyed to the leadscrew) and into the key that runs in the groove in the leadscrew. The pin is pretty small, about 1/16 inch diameter or so. If your apron came without this key or pin, it shouldn't be too hard to drill a key for a new pin. It was near the headstock end of the worm gear as I remember. Good luck finding it! Glen (8342)
Yep--it also locks the nut that threads onto the end of the worm, from unthreading off the worm. (8345)
What holds the pin in place? Interference fit? Its' placement in the keyway? The site where the guy rebuilds the Hercus is very helpful - what a tale! I've decided my $350 10" Heavy was a bargain after seeing what that guy went through! Alternatively, is there an exploded parts diagram available on-line anywhere? Wallace (8348)
Wally, It was an interference fit into the key. The leadscrew keeps the key in place when it's all assembled. It was tight enough in the worm and nut to keep from falling out when the apron is removed from the leadscrew. Glen (8364)
I came home and took the apron off - no hole for a pin in the keyway of the worm. Also, my worm doesn't appear to be held in place with a nut: it looks like there are pressed on bushings on each end that hold it in place. I'm kind of torn now: do I try to make an interference fit key (again) or drill a hole for a pin? The SN on my 10L (170216) puts in in the early 40s. I wonder if they came out with the pin design later, or if that is just a 9" and 10K thing? Thanks again folks - I'll figure something out. Any more suggestions or info welcome. Wallace (8365)
Wallace; This may be an apples and oranges sort of thing as I have a 9 and a 13 but not a 10. On the 13 inch apron, the key is longer than the keyway, and at each end there are ears that press against the ends of the worm. These ears help hold the key in place during assembly, and keep the key from sliding out of the worm, which would happen if the leadscrew keyway had sticky oil or a bit of grunge. (8367)
Wally I think the heavy 10 may approach this differently than the 9/10K. In the parts diagram it looks like the worm key has a step at both ends which protrude axially beyond the ends of the worm gear, such that once the leadscrew is in the worm gear with the key in place, the steps at the ends keep it in place. I also have a sheet from SB describing the replacement of the knob clutch with a lever clutch. After describing removing the apron by sliding it off the lead screw, it just says to remove the key (no mention of pins, etc). Same story in the instructions for reassembly. My first guess is that you may have a key from some other lathe. BTW, the same sheet says that the bushings at the end of the worm are threaded to the worm. There is a pin from the bushing to the worm which maintains their alignment. The same sheet suggests parking the relative position of the collar to the worm gear before removal to allow returning to the same relative alignment (although I don't understand why the pin doesn't serve the same purpose). Frank (8369)
Now I see! I got impatient and made one that is a tight fit in the worm, and put it in place with some Loctite. Now that I hear the description of the one from you and Mr. Stocker, it seems so obvious! If this one comes out, I'll make one as you guys described. Wallace (8370)
Any hope you'd scan and post that lever-clutch-conversion sheet? Does it apply to the 9/10K? (8379)
Wally writes: What holds the pin in place? Interference fit? Its' placement in the keyway? The site where the guy rebuilds the Hercus is very helpful - what a tale! I've decided my $350 10" Heavy was a bargain after seeing what that guy went through! Alternatively, is there an exploded parts diagram available on-line anywhere? Attached is the relevant parts list page from the Army Manual. Anthony (8383)
Evidently it is a 9" and 10K thing. The 10L uses a key that is hooked over on each end to wrap around the ends of the worm. With the apron assembled and the key in position, when you insert the lead screw into the worm it locks the key into position. The key can't shift axially because of the hook on each end and can't shift radially because the worm is on one side and the lead screw on the other. I haven't yet scanned the parts list page so I can't attach it to this message. Anthony (8384)
lurchix I don't have a scanner. In any case, it applies only to the heavy 10, and discusses how to install a conversion kit offered by the factory after they changed to the lever clutch as part of the standard lathe in 1958. The conversion kit was at least several hundred dollars about 10 years ago (it included the complete clutch assembly, including the pinion gear). If somebody needs a copy of the sheet I can snail-mail it to them. Frank (8386)
You reckon the ears-on-ends key idea is adaptable to the 9 and 10K? (8387)
SB 9A clutch assembly
Does anyone have knowledge or an available picture for the 9A clutch assembly on the apron other than the exploded view parts drawing. I took my apron apart to check it over and clean it. I have it all back together except for the shoes, expanders and spring. There are a number of ways these could fit together and I am ashamed to say that I did not pay attention to how it came apart in the first place. Actually, when I took the knob off the front, the clutch assembly fell apart in the back before I could really eyeball it. Anyone have knowledge of how these should fit together rather than trial and error? Brian (9799)
Brian Check out the pictures at http://steammachine.com/hercus/page5.html There are a couple of shots of the clutch assembly. As the text that accompanies the pictures says, "it's a job that needs 5 hands". John (9802)
My lathe clutches had a spring that went in last (I think) to hold the butterfly in place. I didn't see one in the pictures. Maybe three hands and a spring are enough to assemble it. Glen (9803)
Stick the clutch guts in the wormgear, then lay a piece of cardboard against the wormgear and turn the whole assembly face-down on the bench and it's relatively painless to assemble. Don't ask how many times I had to do it before I figured this out. Lurch (9805)
Halfnut slack
This reminds me. How much slack is ok in the halfnuts? On my 9" model C, with everything off I engage the halfnuts and I can use the handwheel to rock the carriage back and forth perhaps as much as 1/16" or 1/8". Does this mean I need new halfnuts or is it normal? Mark (10000)
Slop in the half nut is no big deal you only start and finish the threads in one direction anyway. our big machine at work has a good amount of slop in the lead screw so you need to make sure you back the tool completely out of the threads before you reverse. Kerry (10002)
9" apron question
Does anyone know what the end play there should be on the worm gear on a 9 inch model A/B apron? (10961)
I just got through rebuilding mine, and reported that I got it to 0.003". Then Rose posted that IS the factory spec from South Bend! (10963)
I think you've answered the wrong question. I think your answer applies to backlash in the cross feed screw, Steve was asking about the end play in the worm surrounding the leadscrew which converts leadscrew rotation to drive the automatic longitudinal and cross feeds. Anthony (10984)
Repair halfnuts
Has any one heard of repairing the half nuts by pouring babbit in the? Roy (12074)
There was such an article in either Home Shop Machinist or Machinist Workshop within the past year or two. www.villagepress.com The author removed the worn thread, built up the area using a torch and brazing rod, then cut new threads. Ken (12076)
I finally got around to it. I fixed the halfnuts on my lathe. It's pretty cool and came out pretty well I think. (this got a little long, but I'm a little excited) Built up an angle plate jig out of 4" angle iron. Mounted my half nuts with the proper spacing and then bored them out on the lathe. Chucked up a piece of brass (that was even in the drawer when I got it) and turned it down to a few thousands less than the bored out halfnut. Coated it all good with some JB Weld and let it sit over night. I was going to tap it on my mill but did not have nearly enough travel to run a full tandem tap though the bushing. Set it up on the lathe and used the tailstock to get it started straight and then just ended up hand tapping it. The splitting of the halfnuts was probably the crudest part of the whole procedure and that was mostly due to my impatience (excitement) at that point. I split them using a hacksaw. It came out ok, I would have preferred to use a slitting saw or something similar to get a nice clean, parallel cut. Drilled out the little oiler hole and then put everything back together. First time I tried to engage the halfnuts everything jammed up. Couldn't figure out what was going on. Pulled the apron back off again. Moved all of the levers and what not, and did not see anything wrong so put it back on (again). Everything worked fine this time. First 1/2 dozen engagements or so were a little stiff, but it is very smooth now. After all that, had to find something to thread. Look around a little bit, hey here's a bit of 3/8 rod. Perfect 3/8 - 16. Don't need to pay attention to the thread dial or anything. Just click it in anywhere and it will work out. Having fun now! Jeridiah (13034)
Non-functioning clutch on 10k
The clutch just blew on my recently purchased 10k. Any observations, advice, or instruction? (14616)
I believe you are talking about the clutch on the apron. First thing to do is to dismantle the apron and see if there is any broken parts. You would be surprised to see what can gather in this area on the apron (specially that it is anew lathe for you and you don't necessarily have the full history of the machine). When I bought my 10K that I am currently rebuilding, it was filled with a mix of wood dust and metal filings (and a bit of oil) First remove the lead screw, then the two screws that hold on the saddle that hold the apron. There is a sheet metal cover that protects the clutch, with 4 screws. remove the screws. Be careful when removing the cover, there is a small paper gasket. You don't want to damage it. At this point, you will see the clutch mechanism. To get the clutch apart, you will need to remove the clutch knob. there is a screw in the middle of the clutch knob. Be careful, this a left hand screw! After you remove this screw, everything should come apart. Observe carefully how the clutch parts are assembled. There is a small spring that holds in place 2 half discs. To remove the worm, you will need to remove the split nuts. Then, there is a small pin that has to be removed from the collar (right side when you have it on the table). The key should come out at the same time. Then, turn the worm and it should slide out after a few trial and errors (do not apply any force, there is a position it slides free, the way the worm is cut) Good luck. Do you have the part manual? The explosion view is not very good but useful. If you don't I could send to you a scanned copy of the 2 pages (including the part list) Guy (14625)
Half nut repair
I made a jig to hold my Half Nuts for my SB9 just as they would be clamped up on the machine. I am now ready to do what ever repair I need to to get them back going. I looked at boring them out and putting in a Bronze bushing but it looks like the casting will be too thin if I do that. I am thinking brazing will be the way to go. Does anyone have a clue as to what brazing material I should use or should I weld them up. I plan on boring the hole to size on a horizontal boring mill here at work then threadmilling the acme thread in there so I guess the rod material could be pretty hard and wouldn't hurt anything. Any other suggestions on how to do this repair? I am tempted to just make the hole thing out of stainless billet. No one can see them anyway. (15178)
In the files section, see the folder "RestoredHalfNuts". In this repair an epoxy is used. I believe this guy offers this service, as I think I've seen these on eBay. Jeff (15181)
There was an article in HSM about renewing halfnuts. I made the bracket and bored out the worn threads and filled in the old halfnuts with brazing rod. I used furnace patching material to build a dam to keep the molten brass from running all over the place. The guy Jeff is talking about seems to have a better system. If I was going to do it again, I would try the bronze sleeve and epoxy route. Glen (15188)
I have rebuilt about eight or nine sets of half nuts for 9"/10K South Bend lathes. These have been sold through eBay for $100.00 per set which beats the LeBlond price by about $140.00. I seemed to have saturated the market at this point and business slowed down, so I haven't been listing them for a while. I get the old nuts back in exchange. I have two sets ready to go right now in case you are interested. Their is plenty of room on the castings to bush the nuts. These dimensions are from memory now since I am sitting at my work computer and my notes are at home: my jig is designed to hold the nuts in the same orientation they are in when they are in the closed position on the leadscrew. I use a special tool to get the nuts properly centered, and then bore them out to what I remember to be 0.090". I then make a new flanged bushing out of bronze that has an outside diameter of 0.860", and an inside diameter of about 1/2". The nuts are then taken off the jig, opened and the bushing is glued in using ordinary JB Weld epoxy. The nuts are then placed back in the jig in the proper orientation for the epoxy to set. Next I bore the inside of the bushing to the correct minor diameter for the acme thread. I don't remember what this dimension is at the moment but have it in my notes at home. The nuts are then threaded with an acme threading tool in a boring bar on the tool post. You have to go slow with this threading tool and take small cuts only, since this is actually a form tool and as such, it is being advanced straight into the work. I use an old leadscrew as a gage to determine when the thread is finished. This process is better than brazing and does away with all the distortion and gaps where the bronze doesn't want to go (or where gravity is working against you). Since the bushing is flanged, it is sound in terms of taking up lateral load. Once the thread is complete, you slice the nuts and clean up the surfaces on the mill. I also sand blast the nuts to make them look really nice. I have had no complaints and only compliments. None of the nuts have come back, so they must be working fine. They work fine on on my 9" South Bend. Perk (15196)
9" half nuts
Exactly what should I look for to evaluate the condition of a set of 1/2 nuts? I suppose they should have flat surfaces and sharp corners, but is there something specific? Jerry (15435)
I have rebuilt a fair number of these half nuts and have seen a lot of worn nuts in the process. New half nuts will look like perfect acme threads. The lands on the threads will be the same width as the bottom of the grooves. As they wear, the lands will become thinner and thinner while the grooves will become wider. Looking at the side of the thread that takes up the load, you will over time begin to see a wear line from the leadscrew just above the bottom of the thread. You can use them until they fail, and strip out without sacrificing accuracy in thread cutting. In threading, you always take up the slack in the same direction for each pass, so the slop doesn't affect the operation. Perk (15436)
Half Nuts and saddle questions
Upon further inspection of my lathe, I noticed the Half nuts are warned down for the leadscrew. Also, I could pick the whole saddle up off the ways. The tab that holds it on the side opposite of the apron is there, however I do not see such a thing for the side of the apron. IS gravity trusted to do this job? Also, what should I do about the half nuts? Buy used ones in slightly better condition? OR is there a source for new ones that are not very expensive? (15610)
There is a note in the "files" section on half nut repair. also see 15196 on a source or repaired half nuts. Jim B. (15613)
Thank you, I have read that, and I would do that modification if I had a decent lathe that was operable. I would have to use my Chinese mini lathe to do that boring/threading/turning operation. I'm not sure it would be worth doing on that boat anchor. I'm going to look for some used half nuts in good condition, will check my local classifieds. If anyone on the list would like to sell me an extra pair they have, contact me offline. (15615)
Message 15196 details the process for repairing half nuts. I have posted some pictures of the finished half nuts in the SouthBendLathePics group under "Half Nuts". I currently have a couple of these ready to go for the price of $99.00 plus your old nuts in exchange. Perk (15616)
Just the nuts, or the mounting studs and nuts as well? I was wondering how to contact you because your email is not present. I will have to think about it, If I cant find any used ones locally, I'll let you know. (15617)
You can find the used half nuts on ebay , also there is a seller that sells rebuilt half nuts on ebay if you are talking about you being able to lift up the saddle/apron side that is closest to you, this is normal, the backforce from running keeps this against the ways, there is a saddle lock down clamp available to keep the saddle from moving horizontally when facing etc. Clint(15623)
The nuts you see in the pics file is what you get. I ship them within 24 hours of receiving your old nuts and $99.00 plus $7.00 for shipping (total of $106.00). Or, you can get new nuts from LeBlond for $244.00 plus shipping. Maybe I didn't read your post carefully but I have never heard of someone replacing the studs and nuts also. These do not wear out. I suppose if you had to, you could make them. I'll bet LeBlond would also sell them to you for a tidy price though! Perk (15630)
SB 9A Apron questions
I found a few problems inside the apron. The spring (part #16) is missing from the clutch shaft. Does anyone know the dimensions of the spring? Is it available? Another spring (20A) on the end of the same shaft was also not there. This one seems like a locking thingy. Same questions. What is the thickness of the sump gasket? Is thickness critical? The sump was packed with a mixture of swarf and either heavy oil or grease. Very dry, glad I got in there. I could also use a little coaching on the clutch (shoes, expanders, etc) reassembly. I'd like to get it right. (16961)
Rose Marvin at South Bend Lathe should be able to help with parts. http://www.southbendlathe.com The sump gasket on mine was paper thin. I don't think the dimension is critical. Tightening the clutch knob pulls the shoes in from the center and forces them out to contact the inner surface of the "well" that they sit in. The (20A) spring thingy kinda keeps the shoes lined up with the center shaft. Glen (17022)
Question on heavy 10 Carriage
I got a heavy 10 South Bend lathe with 3-1/2 foot bed. On the carriage on the back part there are two spring loaded steel balls that are on top of it on each side. What are these for? Also on mine it is missing the back part of the cover for the cross slide. The cross slide threaded screw is exposed in that area and I need the piece that goes there to cover it up so chips don't get down in there. I don't have the taper attachment although it looks like one could be installed on it. I can't afford the taper attachment right now but would like to get the cover for the back part. Gary (17412)
Gary, Why not make one out of sheet metal for the time being? I have "Rube Goldberg" or shall we say "creative attachments/lights" all over my machines. Larry (17413)
The spring-loaded steel balls you describe sound like oilers. (17414)
Gary, They are on page #2005 of the Mc Master Carr catalog. Just press on the little ball and it will allow a few drops of oil to get in then reseal after you stop pressing. I too was stumped by them first time I saw mine. Now I feel like I'm not the only one that didn't know that BTW one of mine isn't working right and I need to order one. The ball won't depress. Is there a way to clear them easily, folks? http://www.mcmaster.com/ Tom (17417)
Tom I thought that they might be for oil. Just wasn't sure. I just got back in from the garage. I went through everything on it taking it apart and oiling everything back up with proper machine oil. I understand how everything works and where all the oil goes now. It really is simple once you see it apart. On your sticky ball problem maybe you could spray some WD40 or penetrating oil on it and take a brass punch or similar soft item and lightly tap on it to loosen it up. It is probably full of crude. You might have to take the carriage off and clean it out from the under side. It is really easy to do. Just take the 3 bolts on the back bottom side loose and remove the clamp bar thingy. Then take the two large screws loose up front on top and lift the carriage off. Gary (17418)
Gary. I wanted to try taking off my carriage but those two screws on the front top section of my carriage won't let go. I'm afraid to really force them and bugger up the slots. Might try penetrating oil or something. I never thought of wd40 to release the ball in the oiler. I'll give it a whirl. I'm like you ,I don't seem to really get a handle on how it works unless I can take it apart. Tom (17419)
Tom, To clean the oilers you can try brake cleaner in an aerosol can sprayed in from underneath and you may have to pick out some of the crap with a needle or small pick while you do it. If you can't take the front screws out you can always slide the saddle off of the end of the bed. Remove the leadscrew end bushing and put a wood block under the lead screw for support while you remove the saddle. You will be able to better see inside of the apron from behind and clean that out at the same time as you clean the oilers. JP (17422)
Hey great Idea JP. I'll try that sliding off the end idea as soon as I feel well enough to do it, Thanks. I always wanted to get inside that apron anyway. Tom (17425)
Gary, My heavy 10 did not have the back cover for the cross slide, so I made one out of sheet aluminum and it has been doing a good job. Russ (17436)
Apron worm gear replacement
I am in the process of re-construction of a South Bend 10K lathe, a big challenge. Recently I decided to manufacture a new apron worm gear. My previous gear was in a poor condition.... years of abuse by previous owners. There was the ebay solution..... not a challenge. At first, it looks like something almost impossible to manufacture in a home shop. I found a piece of cast iron round stock 2 1/8 in dia. and cut the gear blank to the original dimensions. Everybody can do that with no difficulty. The problem starts when comes time to cut the gear teeth. As it is a worm gear, conventional method of gear cutting cannot be applied. I made a small jig that holds the gear flat on the compound rest at the proper height so the middle of the gear is at center height.. For indexing, I used a 36T gear from my metric gear transposing set. A small arbor drilled through held the indexing gear on the gear blank with a press fit. I mounted a fly cutter with acme screw profile in a a piece of 7/8 in dia round bar mounted in the spindle. I set up the gear box to 6 TPI and reverse. I cut the teeth like a screw, indexing the gear once in a while. (taking many cuts for one set of teeth at a time. The cutter works up to 5 teeth at the same time. I run the lathe at very low speed. I stopped after each pass, moved the carriage back and increased the depth of cut by 4 to 5 thou at a time. Every time I indexed, I started the depth of cut to 0 again. With the exception of very minor cosmetic glitches during the cutting process, (once getting close to the final depth I realized too late that I was engaging the split nuts with the gear blank too close from the fly cutter... the carriage was not moving yet but the fly cutter was taking a light cut on the top of the first gear tooth of the pass) I ended up with a gear that runs very smoothly in the apron. This technique can be used to cut any worm gear. It is time consuming. It took about 6 hours to cut gear teeth. Couple hours to manufacture a jig that can be used only on one lathe because of the distance height between the compound rest and the lathe center. (has to be within a few thousandth of an inch) In my case, it was done on a Atlas 12 that had the saddle re-ground after I discovered it warped. The compound rest was also hand scraped to remove manufacturing defects. My jig thickness was 0.893 in thick for a 1.190 in from the center to top of compound rest. The fly cutter was running on a 1.42 in diameter path. The worm is 1.375 in diameter but there is a need for bottom clearance in the gear. From the original gear, I figured out a 0.022 in clearance required. I will try to post pictures on the web site next week. Guy (18016)
Apron clutch construction
I own a couple lathes and am looking to add another. I have a couple Chinese lathes, and I'm looking at a full sized SB 10 or 13 for larger projects. I also would like to make a modification to my Import 920 lathe. Back in my shop class days I learned on a SB Heavy 10. I purchased a grizzly G4000 a couple years ago and have been happy with it. I looked at SB's but the beds were shot, the machines were abused or the price for one in good shape was not worth it for a small 9" lathe. Anyways, I would like to modify my G4000 to have an apron clutch like the SB. The lathe already has a power feed, but it is geared the whole way, meaning that if a micrometer stop were placed on the ways, the stop would move or some part would break. I would like to replace the geared feed engage lever with a clutch design based on the one found on the deluxe SB aprons. I have found exploded diagrams of the apron, but the are very hard to follow and very confusing. Has anybody taken their apron clutches apart? What does the Knob/ Lever (depending on year) pull up on to engage the feed? G. (18228)
On my 13" SB Apron Clutch Handle pulls UP to engage. Ron (18238)
The clutch is a multi-plate clutch, with alternating plates connected to inside and outside splines. The outside sleeve (which contains splines on its inside for one set of the clutch plates) has an integral pinion gear which rides on the worm gear which in turn rides on the feed shaft. The (hollow) shaft inside the clutch plates (which has outside spines to pick up the other set of alternating clutch plates) drives the selected feed (when the clutch is engaged). A pull rod which runs down the middle squeezes the alternating clutch plates together, engaging the clutch. On the knob clutch, a simple screw (tightened by a knob) pulls on this pull rod. In the lever clutch, a cam arrangement pulls on the pull rod when the clutch lever is lifted. Does that help? Frank (18251)
Half Nut Repair
Doesn't one of you guys out there in radio land repair half nuts? This "new" 9 inch SB I just got has some pretty bad half nuts. I'd be interested in swapping for a rebuilt set. (18444)
Craig, Do an archive search as there are members here who do the half-nut rebuilds. Also check the files section for info on how to repair them yourself. BK (18445)
There is some files in the drop box for the rec.crafts.metalworking group. Jack (18453)
Check out post 17906. He goes by "Perk in Cincinnati" and I believe he has repaired half nuts on the shelf ready to ship, not just through ebay. I searched the archives for "perk" and found him. Mike (18455)
Craig; I am the one who does the rebuilds on South Bend half nuts for the 9" and 10K. If I can ever find an extra pair of worn out nuts for a Heavy 10, I will begin doing those too. I have a pair currently listed on eBay as item number 3809481581. You can get the complete story on the ebay listing. If you want, you can also email me off the list to conduct a transaction through this list, or to get more information. Perk (18458)
Clasp nuts / Split nut SB 9"
I have a South bend 9" model A that has a very worn out set of Split nuts ( Clasp nuts ) . Does any one know where I can get a set of these at reasonable cost. (18834)
There is somebody on the discussion group that rebuilds them. You trade your old split nuts with $$$, against refurbished nuts with brass/bronze inserts. If you go on the photos, his work is displayed there. Guy (18836)
DW Carter; Depends on what you call a reasonable cost! I am the one who rebuilds half nuts for South Bend 9" lathes. For more information, see messages 18458 and 15196. If you want to see the finished product, go the the picture repository at SouthBendLathePics and check under the file labeled half nuts. The price is $109.00 with exchange of your old half nuts. This includes shipping anywhere in the US. I occasionally list them on eBay also. If you want, you can get them from LeBlond for $244.00. If you have an interest, email me off the list and I can tell you where to send your old half nuts. Perk (18860)
Worn worm wheel SB 9"
I have a Southbend 9" with a very worn worm wheel. This is the worm wheel that encases the feed clutch !. Has any one got a source of reconditioned / used or new units. (18856)
DW; It's me again! (perk in Cincinnati). I just happen to have a complete clutch assembly with a like new worm gear. How I came about this is another story, but what is important to you is that I have it. I will sell it to you for $79.00. Before choking, check out the price of this assembly from LeBlond. If you are interested email me off list. Perk (18861)
If you have some time to spend, can still use your lathe without the gear in place, have basic threading skills, you can cut a new gear on your lathe. I have done it , using a atlas 12 lathe, using a 36T gear as indexer, and lot of time on the machine. If interested, I can send you pictures of my setup as well as pictures of the result. You need to send me a email home as I pick up all traffic from the web site. It is a nice project for a home machinist. What is required: a 7/8 in round stock steel bar some blocks of steel a couple screws a piece of cast iron 2 id dia X 2 in long (extra required to hold the blank in the chuck) a broken center drill 1/4 in dia a lathe that can be set up to cut 6TPI LH a small milling machine or shaper many enjoyable hours in the shop. Guy (18866)
Fitting new half nuts
I just installed some replacement half nuts onto my SB9C. After I reinstalled the carriage I engaged the nuts (without running) and noticed that they were causing the lead screw to deflect downward a slight amount. I didn't measure it, but would guess it deflected the screw by say 0.075 inches. I'd have to think that this extra pressure between the lead screw and the half nuts will cause unnecessary wear. I was thinking about shimming the lead screw bearing at the tailstock end to try and eliminate the bending. Anyone ever run into this and am I on the right track? (21676)
IMHO you will cause yourself more problems by taking this approach. If the leadscrew was ok prior to the halfnut change, then obviously there is nothing wrong with the leadscrew WHY "fix" it. The problem is with the halfnuts, so you REALLY need to fix the "halfnut problem" -- Peter (21701)
Presumably this implies that the top half nut is getting there first. I'd be more inclined to try shimming the bottom half nut (if that's possible) so that the two halves meet the screw at the same time. (21702)
The half nuts are on pivots. No way I can think of the "shim" those. (21706)
One way to move the pivot point is to re-drill the hole oversize, on the desired center and bush it, or you could use an eccentric bushing and make it adjustable. Mario (21708)
I guess I'm missing your point. This sounds like a massive PITA when compared to shimming the lead screw brackets to make it ride a few thou lower. The half nuts are designed to fit in the carriage and track a theoretical centerline. On my machine it appears that the theoretical centerline and the lead screw axis are displaced. If the half nuts were pulling the lead screw up then I could shim the carriage down a bit. since the half nuts are pushing hte lead screw down it seems that lowering the lead screw would be the way to do it. (21710)
Graig, you wrote that there was .075 of movement. That's 7 and a half thou. I wouldn't worry about it. The nuts will where in anyhow. the only time you use them is cutting threads and the lead screw runs slow. Duane (21712)
When I went to school, and that was a long time ago, 0.075" was seventy five thousands of and inch. about 5/64" Jim B(21713)
I can visibly see the movement. It is not quite a tenth of an inch so I guessed 0.075. Yes I agree that is 75/1000 of an inch.(21714)
You're absolutely right, Peter. 75 thousands is a pretty fair amount and with a 9C where your half-nuts are used for turning as well as threading, you'll see accelerated wear. I'm wondering if you bought new or used OEM half-nuts or did you have them bored and bronze inserts installed? If the latter, you might check to see if it looks like the bored out iron body got bored off- center when the old threads were removed to make room for the insert. If that's the case, you might be able to remove the bronze inserts, build up both halves of the iron body with iron-filled epoxy, rebore and reset the inserts. Maybe clean off the oil, blue the nuts and see where they're making contact on the lead screw as a clue? Might be they're tilted enough to make contact at one side or the other first and thereby deflect the lead screw. I'm assuming that the situation exists along the entire length of the bed so that the nuts won't close at all near the tailstock-end bearing support where the lead screw cannot deflect under the pressure? If you ultimately decide to shim, don't forget about also shimming the lead screw bearing at the headstock end. Ed (21715)
Sorry Peter, Sorry Craig for getting you mixed up in my below message. Ed (21716)
It sounds a lot of misalignment to me. Is your apron properly screwed to the saddle? Such deflection could also be caused by the wear on the bed/saddle but never to this extent. Guy (21717)
Jumping in here. You said in your first message that you'd shim the tailstock end of the lead screw. I don't see how that would work. If the half nuts are pushing down on the lead screw, then they're still going to push down at the headstock end when the saddle is at that end. It would fix the tailstock end, but then the leadscrew would be at an angle to the bed. Are you sure there isn't something else wrong? Maybe the apron or even the whole saddle has been displaced down, pushing the half-nuts into the screw? How's the alignment of the saddle rack? (21720)
OK, but you will need to shim both ends rather than just the tailstock end, otherwise the deflection will simply vary in amount along the length of the bed. (21721)
It seems to me that it wouldn't be much trouble to remove the appropriate amount of metal from the pin of the upper half nut. Therefore reducing the downward travel. I wouldn't think that would weaken it too much. Marshall (21722)
Are the new nuts a matched pair, with the same numbers on both halves? If there was a mix up that might do it too. The nuts are bored threaded then split apart later. Jim (21734)
My first impression on reading this was that there must be a piece of swarf or something between the saddle and the apron. Is the apron and saddle original to the bed? I have repaired a set of half nuts per the article in HSM a while ago and I had no problem with alignment. Where did the new half nuts come from? Glen (21738)
Yeah I'd probably have to shim both ends. The lead screw should be parallel to the carriage line of travel. I really didn't get a lot of time to examine the issue along the whole length of the ways. I'm in one of those modes at work and home where "free" time for my own ends is rather limited. I was really doing good to just get the new half nuts installed. (21742)
These are old stock used half nuts from a parter-outer. They still have a good amount of life left. But as you well know the half nut cast iron is soft stuff when compared to the steel lead screw. Unnecessary pressure or side load is just going to wear away nut surface much faster. Definitely though I'll end up having to check the "fit" along the whole bed. One problem though is the lead screw gets stiffer the closer you get to either end of the bed (due to the proximity of the supports). So at either end it may be real tough to see the deflection. (21743)
Didn't check that. Wouldn't have thought of that possibility. Picked them up on Ebay from Jeff Burris. (21747)
Yeah some crud between the saddle and apron could push it in the direction I'm seeing. I thought I had it cleaned but it is easy enough to take apart and try again. The saddle and apron are matched and original to the bed. The half nuts are eBay. I wanted to go fix my old ones with bushings like you did, but finally had to admit to myself that I'd never get around to it. (21748)
Slop in apron handwheel
I have an old Southbend lathe and the serial # is 34124k Cat.# CL0670Z. The apron handwheel has a lot of play. Not so much play in the actual feed, but as if the apron handwheel shaft is worn out. Are there bushings in the apron? If not does anyone know how this can be fixed? Also is it just the tapered pin that holds the wheel onto the shaft? I called the factory before they went out of business, and they told me that it was made Oct. of 1976. But for now I am just concerned about fixing the slop in the handwheel. (24350)
Mine has a little slop also, doesn't hurt a thing but it bugs me. There is no bushing when new. I thought about reaming the apron casting a little bigger and a rounder hole maybe use a shell reamer, than bush my shaft to fit. I think its just a taper pin that holds it all together. (24355)
My '49 9" also was pretty sloppy- I drifted out the taper pin in the handwheel and pulled the shaft. Very little wear at the pinion end, but a lot out near the handwheel. I cleaned up and polished the shaft, then worked a piece of copper shim about 1" deep into the lower side of the gap between the shaft and casting from the front, wrapped around about 60% of the circumference of the hole, then trimmed off the exposed shim and re-installed the wheel. I made the end of the shim that goes into the hole first narrower to ease insertion. Works good so far. There may be a better material than copper for this, but that's what I had at hand. Still some slop but a huge improvement. I'll be paying close attention to the oil hole in the future. Mark (24370)
Mark, I don't think the oil hole is much to blame. It is a poor design. Any time you have a big wheel with a little shaft and one bearing point there will be trouble some day. The biggest thing is fixing it or reducing the slop as you did. Bob (24375)
My nearly 70-yr-old 9" had a lot of slop in the wheel, too; I shimmed it and tightened it up some but the shim didn't last; finally I bored out the hole and turned a cast iron bushing and pressed in; probably last as long as I'll care about. Rick A. (24395)
Worm and wheel drive for 9"
Does any one know where I can get a reconditioned worm and wheel drive for the model A 9" Southbend, any advice will be greatly received. (25124)
I assume you are talking about the worm and worm gear located in the apron. For your info, the worm gear is easy to manufacture if you know how to thread. I manufactured one on my Atlas lathe last winter. All you need is a piece of 2 1/8" dia piece of cast iron, a 36T gear (for indexing), a few blocks of steel to make a jig and a few hours to spend on your lathe. It is not rocket science. Guy (25140)

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