# Help with SB 9C spindle



## carsondarling (Feb 22, 2021)

I recently picked up a South Bend 9" Model C (S/N: 10013NAR8). It has some serious frankenstein modifications, and I'm trying to figure out what parts are original and what has been hacked together.

The biggest concern, is that the spindle appears to be from another lathe, since it's missing the rear gear teeth and just has a gear that spins on the shaft. Has anyone seen a configuration similar to this one? I'm hoping to pull the spindle apart this weekend, but until then I'd love to make some progress at least identifying parts. When I was trying to remove the chuck, I had a belt wrapped around the largest of the spindle drive pulleys and a wrench on the chuck. I was able to get the cone pulleys to spin separately from the spindle (with the pin engaged). Correct me if I'm wrong, but I don't believe that's supposed to be possible.

I also know that the saddle and apron are from a SB9, but the cross feed appears to be from a Craftsman 12" lathe. Does anyone know the dimensions for the dovetail in the SB? I'm not even sure the dovetails are at the same angle. It also appears that the banjo and the left most lead screw bushing are from an Atlas lathe (banjo is an L3-58m), but I'm not sure about the lead screw. 

Thanks for the help!


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## graham-xrf (Feb 23, 2021)

Hi - and welcome to HM . Wows on the Frankenstein lathe, and thanks for the great pictures.
It just so happens that I have taken the spindle out of my SB-9C and (madness!), also out of my SB-9A restoration. Let's try and answer at least the question about the freely spinning cone pulley.




Click on the thumbnail image, and check out the Woodruff Key slot just to the left of the corner of the label tag. That key would normally lock the bull gear to the spindle. The only way the bull gear could turn with the cone pulley, while the pin is engaged, is if the key was missing, or sheared off.

If the saddle and apron come from a SB9, then at least the fit of the saddle to the bed should have the same dimensions  to fit the ways of the bed.
The sketch is one I made up for when measuring the SB9 condition. I don't know where to find actual South Bend drawings, though I am sure they must exist somewhere.




The measure you are asking for is about the dovetail, which is "one level up". In my present chaotic mess, because of COVID-delayed building operations, I would need to move some stuff to get at it, but if need be, I can try and measure the 9A cross slide dovetail. To be clear - you did mean that dovetail, and not the topmost compound dovetail?


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## carsondarling (Feb 23, 2021)

Graham, thank you for the picture! That was exactly what I needed to see.

From that, it looks like I certainly don't have a South Bend spindle, so who knows what's inside there. Sounds like it's time to pull the spindle apart and see what I get.

It does appear that the saddle and apron fit on the ways. That drawing is very helpful though!


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## graham-xrf (Feb 23, 2021)

OK - glad it was useful.
If you are about to take the spindle apart, you may run into a few "gotchas". Please allow that I would not want to be telling you stuff you already know, but I don't know what to assume about what you already found out.

Notice that the spindle bearings each have one of those "right-angle" oiler cups, and a tell-tale little hole just above each. That is exactly the capillary wick system used on South Bend 9's. There is a spring-loaded wick, about 10mm diameter lightly pressing up on the spindle from underneath. These, of course, spring up into the bearing space hole as the spindle is slid out. The little hole is to allow for re-installation. You stick a small rod, or leg of an Allen key wrench into the hole, with the spring wick under it, to keep it clear of the bearing journal hole while you put the spindle back.

At the back gear drive, the arrangement to clamp the back gear nut seems to be a grub screw. On South Bends, it is a split nut with constrictor screw clamp. When you get the nut free, and are thinking about extracting the spindle, think ahead about that missing Woodruff key. It might be in a mangled up state, maybe with a bit sheared off, with edges and surfaces all ready to hurt things you are trying to slide. Be sure that anything on the shaft is free to turn or slide

You can gently tap the end of the spindle with a rubber or nylon hammer, or a bit of wood, but some folk use a long piece of threaded studding, and a piece of pipe with a closed off end, drilled to make a puller, with a nut and big washer on the other end, then they pull it out slowly. I don't know if your spindle even has a Woodruff key. It night be some other arrangement. Whatever it is, as the spindle moves, do not pull it out all at once. As it clears the thrust bearings at the left journal, they will all fall out all over the place. Put some cloth under in case of a fumble. With the thrust bearings clear, it may be possible to slide the bull gear and cone pulley a bit, to discover what is in there.

Keep in mind that if, as you say, the bull gear can be rotated relative to the spindle, there may be only one "right" place where the remains of the locking scheme can slide out. You may have to "feel" you way around until you figure this thing out.

Maybe I am just being pessimist-cautious. Hopefully, it just falls apart. Don't take fright if there is some scoring damage. Let's get a look.


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## carsondarling (Feb 23, 2021)

Graham, thank you again. I sincerely appreciate the time and effort. There's no such thing as too much information and it's so easy to miss the small details.

I've seen a video on how to remove the spindle with the spring-loaded wicks, so I think that part of it makes sense. I hadn't considered that if the key is sheared off, it may present some challenges. Once I get that back gear nut off, I'll take it nice and slow trying to move the spindle. I have a sneaking suspicion based on feel that there's no key at all in there, and someone was relying on a friction fit with the bull gear. That's great advice with trying to get some visibility once the thrust bearings are clear.

With any luck, I'll be able to get the spindle loose today and will be able to see where we are.


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## graham-xrf (Feb 23, 2021)

Just in passing..  on another HM thread, the picture of his Montgomery Ward 54TLC-2130 Lathe (made by Logan) had a spindle cover  and look that was very like yours. Comparing to your pictures, it looked exact, except the bed feet were different. There are also google images of Logan headstock cross sections, showing the spindle, and everything.


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## carsondarling (Feb 23, 2021)

Graham, I wasn't able to find that thread, could you point me in its direction? For what it's worth, the spindle cover is stamped with "2577K3" on the inside.

The spindle was significantly easier to remove than I had expected (though I haven't been able to get the chuck off of the spindle yet...). The Woodruff key was in place, so I'm not sure what was causing the slipping I thought I was getting. With the rougher surface finish, it almost looks like the back end of the spindle was modified, and there might have been an attempt to braze that gear on the end.

The cone pulley doesn't look like a South Bend cone pulley to me, with the oil port in the wrong spot, and I don't think it's quite long enough.

The headstock looks like a South Bend 9" headstock to me and the bearing surfaces seem to be in decent shape.

I'm tempted to try to purchase a replacement spindle and maybe a cone pulley and see how they fit up.


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## mattthemuppet2 (Feb 23, 2021)

I'm going out on a limb here but it looks to me like an SB9 spindle that has had the gear at the end cut off (trashed maybe?) and a short stub welded in. If you have a look down the spindle from the chuck end you should see a step (the end of the stub) if that's so. The through hole should also be 3/4", that's another way to check.

If it works the way it is I would lube everything up and use it as it is. You can fix the cone pulley misallignment if you need to later. 

Use the snot out of it and keep your eyes open for a lathe with a quick change gear box (did you get change gears with this one?). Might be 3 weeks, might be 3 years, but in the meantime you'll be having plenty of fun with this one!


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## carsondarling (Feb 23, 2021)

Just checked the spindle, and it does have a 3/4" bore, and there's no step. I agree though, it looks like the gears were cut off one way or another. I did get a full set of change gears with the lathe, I'm just not sure yet if I'll be able to match them up with the lead screw or if it'll need a new lead screw as well.

That's great advice Matt, hopefully I can get the mismatched cross slide to work well enough to be serviceable until that next lathe pops up. It definitely seems like the Salt Lake City area has fewer of these machines available than the east coast.


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## mattthemuppet2 (Feb 23, 2021)

you know, it just occurred to me that the gear on the end of the spindle (cut into the spindle on SB9A/B/C) has probably been turned down to what you see now = no step. Seems like a pretty reasonable repair if someone trashed that gear. Good that you got the change gears, that's a big deal. As long as everything moves smoothly and moves no more than it should, just give it a whirl and start making chips. You shouldn't have any problems selling it if you decide to trade up in the future and you never know, this might be all you need for what you want to do. You can make a lot of neat stuff on machines that others might dismiss as junk.


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## malleusmagnus (Mar 4, 2021)

FWIW, based on IMG_3252, it looks like your lathe was originally fitted with a taper attachment.  It would bolt on in place of what appears to be a cover on the far end of the cross slide.

I have a "transition" 9" myself; it was apparently produced before the A/B models and before the C model became a C, so it doesn't have a Q/C gearbox.  Since I'm not planning to be using it for anything that remotely resembles production work, I'm not too concerned about the Q/C gearbox.  Changing gears doesn't take all that much time (yes, compared to the gearbox it does), and if I need to change feed speeds during a setup, I plan for it ahead of time anyway, so not that big a deal to me.


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## carsondarling (Mar 4, 2021)

That very well may be the case. I know the bed is from a Model A, though I clearly no longer have the QCGB or the apron/saddle.

I think the cross slide, and the cover you're seeing is actually from an Atlas lathe, so who knows what's going on there.

I finally got my hands on a new spindle, and got it installed today. It's great to actually be able to drive the gears and see it move. With the current setup, I believe I can get everything working on the change gears with just a couple of spacers.

However, I've come across a new problem, and in doing so, found the source of the slipping I was talking about earlier.

It appears that the pulley cone that I have is not from a South Bend, and I now believe it's been cobbled together and will not work as-is. The center piece of the pulley (with the notch for the pin from the bull gear) is actually machined and inserted into the pulley. The slipping is along the red line I've highlighted. It's getting worse as I add more drag to the lathe with the change gears. I'll either need to fully fix that insert in place somehow or get a new cone pulley.

What are people's thoughts about drilling through the pulley and adding a set screw to fix the inner cylinder?

Otherwise, I've made a few chips with the lathe and am hoping to get some time this weekend to work on restoring the cross feed screw.


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## malleusmagnus (Mar 5, 2021)

The best solution for a shear pin would be to install it so that it's in a double shear condition.  Not seeing the rest of the part, I can't offer a better solution.  2 set screws, 180° apart, would be best in terms of torque reaction.

It'd be hard to pin down what the weakest link in the driveline is, the smallest gear teeth (I offer that only because of the age of the metal; ordinarily, I'd ignore them as bulletproof) or the drive belt slipping.  If you're using a leather belt, I'd belt on the belt.  If you're using a serpentine automotive belt, I wouldn't want to guess.  Failing that analysis, it'd be hard to size the screw(s) so that they would truly drive the spindle and not act like a shear pin.

Maybe the best bet would be to use the HP of the motor to size a screw (or two) so that it (they) wouldn't shear.  At least that way, whatever did break, if anything did before the motor stalled, would bed exposed and easy to find.  If you have the original 1/2 HP motor, two #10 screws would do it.  If you don't have/can't find a 10-24 tap (I wouldn't use a fine thread), just go up to 1/4-20.


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## brino (Mar 5, 2021)

Personally I'd consider a permanent loc-tite solution.
But I'd want to separate the two parts and clean/de-grease first.
There should lots of surface area for the bond to work.
-brino


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## malleusmagnus (Mar 5, 2021)

brino said:


> Personally I'd consider a permanent loc-tite solution.
> But I'd want to separate the two parts and clean/de-grease first.
> There should lots of surface area for the bond to work.
> -brino


That's a thought I hadn't thought 

Just for grins, I looked up the shear strength of Loctite 638; it's advertised at 4.5ksi, which, given the large amount of surface area between those parts, would be ideal.

I just wonder about the design gap for Loctite, though. As advertised, it's supposed to be 0.25-mm (0.009-inch), which means there won't be any metal to metal friction component of the fit (that's a pretty loose slip fit), so you're relying only on the goo.  It'd be worth trying, though; it's waaay cheaper and simpler than messing around with set screws, and, if it doesn't work, you've only lost the time in applying and removing it.

I wonder if there's that much clearance in the two parts.


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## carsondarling (Mar 5, 2021)

Thank you both, malleus and brino!

I'm going to pull the spindle apart again today and see if i can get the two pieces separated. If so, I'll give the Loctite a shot, if not I'll likely end up trying to add in a couple of screws and see what happens.

I believe the motor I have is actually only 1/3hp, so I think even the #10 screws wouldn't be the weakest link. That being said, I would probably go for a larger pair of screws just in case.


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## carsondarling (Mar 9, 2021)

To follow up on this, I ended up epoxying the inner wheel in place. So far, it's holding up. If it doesn't continue to work longer term, I can always go after mechanical means of securing it, or replace the cone pulley entirely.

With the cone pulley and spindle sorted, I was able to get started on fixing the cross slide screw. The lathe had been tipped and the cross slide screw had broken where the handle attached. I machined the face flat, bored a hole, and then turned an extension for the handle to mount on. The surface finish is atrocious (I'm blaming having to use the compound as a cross slide, though in reality it's just my lack of experience showing through), but the extension functions and I now have a functional cross slide. I even managed to cut a keyway into the extension with the lathe.

Next up is making some spacers for mounting the SB change gears on the Atlas banjo!


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## malleusmagnus (Mar 9, 2021)

FWIW, there are several SB 9 banjos on ebay for around $50.  Search for "South Bend Lathe" and sort by lowest price first.  I would make a lowball offer. These aren't steady rests; they don't seem to move much.

The seller "jackjessica-us" (no affiliation) is near me and seems to have a really good unadvertised store of parts at reasonable prices.  I'd personally try him first.


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## carsondarling (Mar 9, 2021)

I actually have a SB 9" banjo ready to go. Unfortunately, this frankenstein of a lathe doesn't have the right lead screw support (let alone lead screw) to use it. As is, I think I can still use the gears, so for the time-being it'll work. Longer term, I will hopefully swap back to a SB lead screw and get this lathe closer to original shape.


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## malleusmagnus (Mar 9, 2021)

Someone also posted a set of leadscrew brackets, pretty cheap, as I remember.  Same site.


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