My brother and I just purchased an old South Bend lathe. It came complete, with a bunch of miscellaneous tooling and parts, and a cheap-o jet drill press converted to a rudimentary mill. It also ended up coming with a pile of musical instrument tools that we've sold for nearly what we paid for the whole shebang, so we've only got about $20 into the lathe and drill press.

It wasn't particularly well cared for, and it was covered with shavings, dust and crud, but once we got most of that brushed away, it doesn't look too bad, except for some dings in the rear way right underneath the chuck.



I'm new to machining, although I've done some blacksmithing before. So I'm bound to have a bunch of beginner type questions in the near future.

here's a few to start with.

The serial number is 70906, and if I'm looking at the right place, the date is is 6 2 36 S. What model is it? From looking at pictures online, I'm guessing 415. It's a 9" swing and a 3 1/2' bed.

We disassembled it to move it, and found a couple of shims under the headstock against one of the ways. Is that a normal thing?

What else should I be looking for as I clean this thing up and put it back into service?

thanks!

NO: shims under the headstock is not normal from the factory. The only reason I can think of for this is that the headstock had been changed. Your lathe is an early model 9 workshop made approximately 1936. There are a few differences between the early model 9 workshop and the later model 9C. One of the differences is the changed gears. Although you never know, this could be changed as well.

You can go to The SBL Workshop - Home and get most of the information you need. A thorough cleaning and inspection is definitely warranted on this machine. It's a very simple machine compared to some of them, but if the headstock has been changed you may have a misalignment problem.

the lathe bed seems to be in good shape, which is definitely a good starting point. you don't have much money in it so you can afford to spend a little bit extra to get it right. And when you're done you should have a real nice machine.

promacjoe

You lathe looks to be a 405. It is an earlier version of the SB 9. Yes, you need to go the the Yahoo group for SB lathes. Jim or Turk. I think Jim was elected as the 405 guru. Look at your lead screw. It is should be left handed. I did have a 405 Franken lathe. Basically the bed and few other parts were 405. I bought a tailstock off e-bay and it was a 405 tailstock. I'll have to relook at your picture. The beds were machined, so don't go looking for fish scales or frosting. Also, there is no bronze bearings. I think rule one is to defentaly clean the spindle bearing. The threaded spindle is smaller than a regualer SB 9, thread wise. I believe you can swap in a newer spindle if needed. I think the change gears are 16 dp as compared to 18 dp for regular SB change gears. This is actually good if you are going to keep it as change gear. I think Boston Gear still makes 16 dp gears. I remeber the hole in the gear housing bracket as being smaller than a regualer SB 9. Also the saddle might not have the cut or window for the cross feed gear. These didn't have an 'A' or "B' model. I hear that the bore of the cross lead screw is iradic. SO, if you want to upgrade to 'A', then you'd need a new saddle.
The angle shot on the tailstock, I can't tell if it is 405 or regular. The 405 is skeletonized, or you can see thru it. You headstock looks original. I hadn't heard of shims on a SB 9 headstock.
Also, you have an Aloris tool post. I don't know the size, I am guessing AA. It is the piston type. A little less accuracy than the wedge type, but for your lathe more than enough. I'd look at Aloris's website for an explanation. I have both, in the BA (piston) and BAX (wedge). The wedge holders will fit the piston, but not the other way. At least that's my limited experience.
Tom
Edit: one thing bothering me. From what I've been told, the 405 had a reversing gear, instead of the lever. I see a lever on the headstock. Again, mine was a franken lathe, with a newer headstock. Can you measure the width of the bed? To some extent, I am somewhat thinking 9 JR or 10 JR. I am not really familar with those lathes though.

This is not a 405, it is a 415 bench lathe. the 405's were replaced in 1935 in-between serial
numbers 59800 and 59900. This serial number (70906) is a 1936 shipped probably between
Oct and Nov of that year. The bed casting date of 6-2-1936 shows that it would have been
used aprox with in 3 months of this date. Turk and I have just about proven that this was
not a "cast date", but a ready to use date. The beds were cast before this date and
seasoned for a period of time.

The major information on the differences between the Workshop models can be read here:
The SBL Workshop - 9" Workshop information

Steve Wells

thanks for the responses!

I welded up a heavy steel workbench for it the other day, and today started cleaning it up and reassembling it. Before I can do anything I need to redo the wiring harness with the switch; it's really messed up and frayed. Also ran into some trouble with the toolpost, as the t-headed bolt that runs up and down through the tool post was all buggered up and broken underneath, with a very lame repair done to it. For now, I might just weld it up and machine it clean again, and think of making a new one as a first project. Also looking on ebay for a regular, older style of toolpost to have one as a spare.

For now, I've been advised to replace the shims until I know why they're there. They are .003".

The spindle has no end play or side to side play and it turns, but very stiffly. My brother said that when he first looked at it and ran it, it would only run in the low gear, and stalled in anything higher. He thinks the bearings have been cranked down too tight. Any advice about that? Haven't run across that information in any of the books I've been looking at yet.

thanks again!

"I welded up a heavy steel workbench for it the other day, and today started cleaning it up and reassembling it....."

Photos would be fun....

"I might just weld it up and machine it clean again...."

I like your way of thinking.

"He thinks the bearings have been cranked down too tight."

Very possible/probable. Make sure they are well lubed and loosen the bolts, the spindle should turn freely by hand.

I went ahead and welded up that t bolt after all. The t nut on the end seemed to be cast, so it made a pretty ugly weld, but since it was already broken, i didn't figure I could make it any less useful no matter what I did. I cleaned it up on the grinder and it fits as good as it ever did. It should hold until I come up with a proper replacement.

I didn't get around to looking at the bearings today, maybe tomorrow. I'll put a link to some pictures after I sort through them and put some on flickr.

The big problem I discovered today, though, is that there is what seems to me to be an unforgivable amount of end play in the cross feed, several thousandths of an inch at least. I looked up on the wswells.com page and saw that there is a lot there about this, but it looked like I need to have an already working lathe, and some level of skill in order to perform the repair. Not sure how I will deal with that...

It really depends on how much slop you do have. Turn the handle one way and get the crosslide moving. Then reverse directions. See how many thousands the dial turns. There is debate as to how far the dial turns, as to when to replace components. I would say 1/2 to 3/4 turn is getting to the point where you need to replace parts. I think on mine the threading nut was made out of steel. I replaced it with a new one made or brass or bronze. It took out a lot of the slop. I think I had about .030 to turn and with the new bushing, about .005 to .010.
As for using your present lathe for the repair, you could lock down the saddle and then use the compound, turned 90 degrees to bore the hole in the cross feed screw.
Tom

I get .022" of slop, measured on the dial, if I back it up and then go forward again.

The repairs that I was reading about involved cutting the threaded shaft off, drilling out the gear, and fitting a new threaded shaft to the gear. There was some turning work that had to be done on the new threaded shaft, that I think would be hard to do without a tool post, but maybe I'm missing something obvious there. I am totally new to this stuff.

In one of my posts somewhere on this forum, I mentioned that my cross-feed had about .005-.006" of slop. I was told that there are brand new machines out there that would be envious.

Wayne

That's not really very much backlash. Yeah, you can get down to single digits, but it's a long path from here to there, and at the end of the day, you still have some backlash to account for. It's not like you can ever really get away from "go the other way first then creep up on it" as a means of taking up the lash on the works (at least without going to ballscrews).

Regards.

Finegrain

As others have said, not much of a worry at .022. I would use it as is. You could try and just replace the nut itself. That might at least take up half of the slop. Also, your tool nose pressure puts the crossslide back, so you really don't have any shift in the tool with most machining you'll do on your lathe. I'd cut some metal and see how you do. If you do OK, then machine some more. Just be sure to get your tool nose to the centerline of the axis. A center in the tailstock is good to match the tool nose to.
Tom