'O' 15in Questions

Just recently bought an old South Bend 15" and I've got some questions I hope ya'll can help with. This is a 5' bed series 'O' dating from 1920 per the serial card. It seems to be in pretty good shape, looks like some bed wear (based on slide getting tight as it moves toward the tailstock - I suspect it's adjusted to be snug on the worn section which makes it too tight on the unworn area) but it doesn't seem too bad. Also got about 1/16" of slop in the cross slide lead screw. On the other hand it was cheap, works and seems in good shape so I couldn't pass it up. I've got a little sherline and had some experience with that along with some time on larger lathes in various classes and shops. My dad also has a 9" that we've worked with a bit but never gotten much into.

So, my questions:

1) What is the headstock taper / chuck thread? I find some info that says it's a sb specific taper and some that says a Morse #3 (I think). Likewise, some info says 2"/8 thread but I've seen a few other things too. I don't actually have the lathe yet to check it myself.

2) I'm going to need to get centers and a faceplate(s) for it - what other model gear will fit? I assume if the taper is a standard Morse it should be pretty easy to find centers, but if it's not I'd like to know what else will fit so I can search e-bay and such. Same with the faceplate.

3) How close are these units to the later 9" in construction? We have the 'How to restore your 9" south bend lathe" book and I'm curious how much of the info in that book applies to the big girl. I know the apron is different, but is anything else that different?

4) How do you adjust cross slide lead screw end play? As near as I can tell the majority of the slop I have is the screw moving, nut nut/screw wear. I assume there's a thrust washer/bearing somewhere that needs to be replaced.

5) One of the things I'd like to do is to make an adapter to use the steady rest we have for the 9" on this lathe. Anyone done something similar? How did it work? I was planning to build it up welding some plate together (making sure the surfaces with properly aligned of course) and do some creative machining/fab work to get the 'v' grooves setup.

Thanks,
~John

The spindle thread is 2 1/4-8 the same as the heavy 10L. But the 15" has a longer thread so if a heavy ten chuck or faceplate is used you may need a spacer between the chuck and spindle flange to get the chuck tight. Not sure as the taper inside as i haven't got far enough to make an adaptor and i never found anything written on the 15". As far as the steady rest i have plans on making a plate to bolt to the ways and use my 10K steady on it as you talked about. Do you have any pics? I have a 1919 15" and had a 1917 15" ...Bob

Okay, so will any 2 1/4-8 faceplate/chuck fit, or do I need to be looking for only south bend type?

I'll get pics once I get it setup and cleaned up a bit - don't have it home yet.

Thanks!

jaluhn said:

Okay, so will any 2 1/4-8 faceplate/chuck fit, or do I need to be looking for only south bend type?


Thanks!

Click to expand...

Any 2 1/4 8 should fit. Like i said you may need a spacer and i can help with that if needed...Bob

Bulletin 100 dated 10-20-33 says 15" nose is 2 1/4" - 6.

johnoder said:

Bulletin 100 dated 10-20-33 says 15" nose is 2 1/4" - 6.

Click to expand...

I thought the same thing for years. Then i measured it. OR the early 15" were different like ours. Here are some pics i just took.
pic 1 15" 2 1/4-8 nose with longer than normal thread
pic 2 10L dog plate on 15" spindle. Showing end of spindle sticking thru.
pic 3 10L 2 1/4-8 nose
pic 4 15" dog plate on 10L. The 15" plate is thicker to make up for the longer thread. Which a chuck may not screw all the way on if the spindle bottoms out on the back of the chuck...Bob

Good info on early stuff Bob - thanks

There is another situation like that with the old style 13,and heavy 10 lathes they both have the 1 7/8"-8 thread on the spindle,but the one on the 13" is about 1/8" longer.I got a N.O.S. heavy 10 drive plate from Plaza to use on my 13,but had to make a spacer ring out of high tensil strength bronze to bring it out flush.The ring lives in the original box with the original oily paper and the plate.

Well engineered motor mount. The motor has been removed for clearance. It's setup with a 1Hp 115/230 1 phase motor



It looks like someone faced the end of the spindle - maybe due to the extra nose length Bob mentions? The machine came with a 6" 3 jaw & 8" 4 jaw chuck. The 3 jaw fits, haven't personally checked the 4 jaw yet but was told it worked.



Ways seems to be in okay shape.... some dings but no serious wear ridge I could find. The carriage down get pretty tight on the tailstock half of the bed which I take as evidence of wear on the headstock end (gibs tightened to make it snug on worn section makes it too tight on less work section.) Can still traverse it all the way though it's tighter than I really like if I was going to use that section of the bed much.



I also found several broken gear teeth on the cross feed drive gears, (looks like someone ran it into the stops under power and the gear was the weakest link) spindle backgear (but none on the mating backgear oddly), and a at least one of the leedscrew drive gears. Nothing that keeps things from working though. Also, the half nut is completely missing though that's going to be a big problem since I don't have any change gears anyway. The compound rest gibs are a bit loose as well.

I also have ~0.030" slop in the compound rest lead screw thrust washer, and about 0.050" in the cross slide. From what i can tell the leadscrew/nut is pretty tight, it's all in the leadscrew thrust washer or whatever is used. Looks like this will be pretty easy to fix with some shims under the handle though.

A more significant concern is that the headstock bearing has ~0.010" of axial play and some significant roughness on the bearing surfaces. Doesn't look like there's been much contamination of oil starvation, just wear. However, the adjustment seems to be bottomed out. Anyone else dealt with this this? I'm thinking the best approach is going to removing the bronze inserts, putting about a 0.005" shim between the bearing shell and casting and then shaving the bearing shell mating surfaces (looks like it's worn to where the shells are tight up against each other, so adjustment is going to require removing a bit of metal here) to get the proper clearance. It looks like clearance is supposed to be set by shims between the bearing cap & the headstock bottom casting, is this correct?

Taken before I got it home and cleaned the dust off....

Looking pretty good. Mine has shims under the bearing caps...Bob

Thanks! I think with a bit of work it'll be a pretty nice machine. Certainly can't beat it for the price ($500)

I've got the steady rest and some tooling off a 9" that I am hoping to be able to use on the big girl and it's impressive to see much much bigger everything is on the 15.

Any thoughts on how much of the info from the 'How to restore your SB 9" Lathe' book would apply to the 15"? I know my dad has a copy of this, got to see about stealing it from him.

Thanks!