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South Bend 12-3/4 Lathe Runs Again


Mar 19, 2020
USA, Northern Illinois
I recently finished most of the refurbishing on the SB 12-3/4 lathe, the raised-swing variant of the Heavy 10. The catalog number is CL125A, and I originally posted the serial number (13680RKD16) nearly 2 years ago here:

Well a lot has happened in the meantime, but I finally got it torn apart, put back together, and running well. About 80 – 90% of the work was done from mid-March to Mid-August of this year. That was nearly all of my spare time, evenings and weekends.

South Bend shipped this lathe in September 1963 to Tranter, a dealer in Pittsburgh. My dad acquired it in the mid-90's via sealed bid from a school district in western Pennsylvania. Dad had been trying to give it to either my brother or me for the past 10 years or so. As my parents were moving out and into retirement living, I decided that I couldn't bear to see it sell for peanuts at a rural Pennsylvania auction. So I rented a 16' box truck and my son helped me fill the truck and haul this and a bunch of other shop stuff to my home in Illinois. This was in the first 6 months of the pandemic. I had been spending my pandemic time by refurbing my extra-deep garage with a good cleaning, epoxy paint on the floors, and a small dedicated, enclosed shop space in the back.

I bought the full Ilion kit from Mr. Brooks. I knew that some of the felts were falling out and the whole thing needed a good cleaning, so I decided to completely disassemble and give the machine a new start in life. The Ilion book is essential, and so is the PM forum here. For questions that came up that weren't specifically addressed in the book, I almost always found answers/viewpoints/debate here on the forum. So I need to thank everyone here who contributes their time and expertise to make this such a great resource. I also bought a few parts from Ted (SBLatheman) along the way.

Although the lathe was really dirty, it was mostly lubricated well, the exceptions being where felts were missing. The only significant rust was on some of the knobs and hand wheels. Regarding wear, it's difficult for me to quantify, but I think it's much better than some that I've read about here on the forum. The spindle journals and bearings have no scoring. The old spindle felts were black, but in place and fully saturated with oil. The bearings and spacers are in good shape, so it appears that the proper procedure was followed when the bearing caps were pulled. It still has thin shims available to remove if needed. The half-nuts and lead screw look to be in very good condition. The compound and cross-feed screws have backlash of no more than 15 – 20 thou so I think that's good and now I don't even notice it in operation. Looking at the compound screw, I can see that the threads near the center are just a bit thinner than at the ends, but it's not extreme. The front v-way for the saddle does have some gouging, with matching gouges on the saddle itself. I'll add some pictures in a later post. I did buy a pair of precision-ground flat stones and used them to remove some zits from the sliding surfaces before assembly.

Overall I think this lathe will be fine for learning and making the parts that I want to make. I've done a few cuts and yesterday made a replacement thumb screw for the compound dial lock. Compared to smaller lathes that I've used, my initial impression for turning, threading, parting is that it cuts like butter. In the coming weeks, I hope to progress with more precise leveling, alignment, etc. and I know I've seen some threads on PM with some good info on those subjects.




Thanks guys. I'll admit that my brush paint job didn't come out as well as I hoped, but it's more than adequate for me and this machine. But nothing close to the (better-than-factory) finish on this one:

Here are a few pics of some of the worst wear that I saw.
This first one is in the apron, part of the clutch. There was a shaft with similar scoring in the gearbox. In both cases they had lost the lubricating felt, and no telling how many hours of operation they had without proper lubrication. I smoothed them a bit with some fine sandpaper, cleaned, and put them back together.

This is the front V-way:

And this is the matching way on the underside of the saddle:

I will see how it performs. When I pull the saddle for cleaning the next time, maybe I'll blue it just to see what the contact area looks like.
Never heard of a 12-3/4" South Bend

Ted has a nice one. I have imagined that SB marketing required the raised swing version to be less than 13" to avoid confusion. Even though the SB 13 is much heavier and more rigid. But I think the raised-swing 16 added 50% for 24-inch swing.