9" Southbend Headstock reworked

I am cleaning and getting ready to paint anew an old 9" Southbend. I took the spindle out of the headstock, so I could clean the oilers etc, and to my astonishment saw a bunch of micro-fine brass particles around the rear bush. I continued cleaning, and after I had cleaned the grease and particles out, I found myself looking at a pressed in brass bushing inside the original South Bend brass bushing....I think.... The front bushing had a similar pressed in bushing. I am saying that the headstock casting has two concentric pieces of brass in each spindle bearing location.

So...My question is what do the original bushings look like? Are they in two pieces like my lathe? I might add that the workmanship in these inserted bushings is very high, judging from the finish. Haven't miked them for accuracy yet. But, if it was not done at the factory, I need to make a bunch of measurements to make sure I have an aligned spindle. And be wary of the fit when re-assembling the headstock. I cannot imagine boring the two holes to great accuracy at the correct height and parallel to the bed without considerable fixturing, such as would be available at the factory, but not in the local machine shop.

All in all, a bunch of complications I could do without!

Reply to
brownnsharp
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Original SB9 bearings were just highly-finished holes in the iron headstock. The polished hardened spindle let a setup like this run almost forever. Sounds like your original bearings wore out and were bushed.

GTO(John)

Reply to
GTO69RA4

Two measurements with a dial indicator across the spindle with the pulley removed should give you a quick answer. one with the indicator on the top of the spindle and another from the side. With the indicator base on the carriage, it should tell you how close they are. We have rebored headstocks in the shop, small ones on the Bridgeport and bigger ones in the jig bore, it's not rocket science, indicate the V in the headstock to vertical in both planes, and bore.

Reply to
Lennie the Lurker

Reboring something like that headstock wouldn't be too hard with the availability of a somewhat larger lathe. You'd just need to fasten the headstock onto the carriage on the other lathe and use a boring bar between centers through the bearing holes, line boring, it's called. Getting everything lined up, shimmed up, fastened down and the cutter protrusion adjusted before beginning is the real trick. With the proper cutter geometry, you can end up with a very nice surface finish and the holes on both bearings will be aligned with each other. Whether they are aligned with the lathe bed depends on the skill of the machinist. Takes minimal tooling but a fair amount of skill in setting up.

You'll probably end up making a test bar anyway, no telling what it's been through.

Stan

Reply to
Stan Schaefer

Exactly! I know it can be done well, but was it?? Boring it parallel AND getting it to line up in height with the original tailstock requires more than casual attention to detail. With a big enough milling facilities, you could mount the whole lathe bed on the mill, zero in on the tailstock, indicate parallelness to the bed, and bore away.

I was surprised from the response that S.B. bored the cast iron of the headstock for the bearings. The only lathe I had heard of that did that was the Myford ML10 I really don't have a problem with the concept.

At my present rate of work on the lathe, while painting the house, and doing other things, I will probably know what the lathe is like sometime near the end of summer. I have another old southbend, that I use every week, with a good headstock and a bad bed that I might swap parts with if this one is too bad.

Reply to
brownnsharp

Which is typically why the headstock is fitted first, and the tailstock is done to agree with that.

Doing the headstock bore requires that it be a) at the correct height, b) aligned in the vertical plane with the bed axis, and c) aligned in the horizontal plane with the bed surfaces.

Jim

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Reply to
jim rozen

When you have the headstock set up for boring, would it make sense to bore for some sort of tapered roller bearing to replace the stock sleeve bearing?

Thank you, Jeff Rininger

Reply to
Jeff Rininger

No, not on a 9" south bend. The ones where the steel spindle runs right in the cast iron headstock casting don't really have enough meat around the bearing to put in a tapered roller bearing.

Because the bearing has to be shim-adjustable by clamping down on the clamp bolt, that region has to be thin enough to flex and close down when the shim is removed and the bolt tightened.

It's not clear that tapered roller bearings are really better in this application, either. Those journal bearings in those machines may well be one of the most widely disseminated kind of spindle ever made - south bend must have made a bazillion of those 9" machines, and most of them are still out there kicking around, working.

Jim

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Reply to
jim rozen

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