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Reverse tumbler adjustment for spindle wear

jwearing

Hot Rolled
Joined
Aug 26, 2017
Hello,

I am trying to get my 10L running, and I'm having trouble getting the reverse tumbler gears to mesh correctly with the spindle gear. I have found a couple threads about this but in these cases the gears were worn and loose, and in my case the gears are too tight to engage the detents.

My lathe has the cast iron spindle bearings, and they are very worn. The clearance is about 0.030" in the rear and I think the spindle is sitting much lower than it was originally. Engaging the upper detent on the reverse tumbler will actually lift the spindle about 0.025" - obviously not an option once I adjust the bearings or even if the belt is tensioned. Even in the neutral position, the gears don't fully disengage and the gears will buzz against each other.

I think my only option here is to bore / plug / redrill the detents. But am I missing something? Has anyone else had the same problem?

At what point am I better off replacing the headstock?
 
If I'm reading this right, you can grab the spindle and clank it up and down .030" on the gear side ? If that is correct, I would never hit the power button until that is fixed. I can only think all kinds of bad things are going to happen if there is that much. Does the chuck side of spindle have that much play too ? Are the caps stacked with shims ? Is this babbet bearings or what exactly are you looking at ? .030" isn't wear, something wrong, missing, or it melted down without an operator present. Maybe some pics.
 
"At what point am I better off replacing the headstock?"

If what you wrote is really the case I would say now is a good time.

given your machine was outfitted as a turret lathe with a lever collet closer it was likely ran at high speed with the gear train disengaged for extended periods with little attention given to oiling.

Bad for the headstock but overall good for you since the machine would otherwise be relatively unworn in that scenario.
 
The word junk comes to mind. Your observed fault justifies a very serious look at the rest of the lathe for wear. The amount of labor (think cost) would very likely exceed the value of a good replacement. I think you should consider parting the lathe out to recoup as much as possible of your purchase.
 
If I'm reading this right, you can grab the spindle and clank it up and down .030" on the gear side ?

Yep.

If that is correct, I would never hit the power button until that is fixed. I can only think all kinds of bad things are going to happen if there is that much. Does the chuck side of spindle have that much play too ? Are the caps stacked with shims ? Is this babbet bearings or what exactly are you looking at ? .030" isn't wear, something wrong, missing, or it melted down without an operator present. Maybe some pics.

The shim stack on the gear end is about 0.030 thick and I think I will be able to get it within spec, but I will have to remove almost all of them. How many shims did South Bend supply with these machines?

It looks like the previous owner was screwing with the chuck end because the brass shims have been removed and there are a couple paper/card shims instead. The clearance is about right, but I plan on cutting some new brass shims before using the machine.

The bearings are iron - I will take some pics tomorrow.

"At what point am I better off replacing the headstock?"

If what you wrote is really the case I would say now is a good time.

given your machine was outfitted as a turret lathe with a lever collet closer it was likely ran at high speed with the gear train disengaged for extended periods with little attention given to oiling.

Bad for the headstock but overall good for you since the machine would otherwise be relatively unworn in that scenario.

I would hope so, but on the other hand I don't want to sink more money into a headstock if the machine is a junker. The ways have some wear, the lead screw is ok. I will take a closer look at the apron tomorrow.

The word junk comes to mind. Your observed fault justifies a very serious look at the rest of the lathe for wear. The amount of labor (think cost) would very likely exceed the value of a good replacement. I think you should consider parting the lathe out to recoup as much as possible of your purchase.

Not exactly what I wanted to hear, but I did get the machine for a decent price and I think I can still cash out.
 
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If the spindle sits too low to allow you to engage the reversing tumbler, then taking shims out of the bearing cap(s) is not going to fix that. The spindle will still sit too low even if you can get the caps to come down to reduce the clearance. I think you need to shop for a headstock or a new lathe.
 
30 thou is a tremendous amount of wear. That should be easily visible in the bearing. That would either have to have tons of run time, or just run time without oil to wear that badly. Either would make me question the rest of the machine honestly.
 
Wow, I've never seen one with the segments nearly worn away. I would consider replacing the headstock with a later bronze bearing model.

allan
 
I have a stripped headstock off a parts machine just like that with no visible wear. Doesn't mean there isn't any but it doesn't look anything like that. If you want to pay the shipping from VA to CA you can have it. It won't fit in a flat rate box so it would have to go UPS and would likely cost a kidney but the offer is there.

That is very generous, thank you for the offer. Before I accept, let me spend the day evaluating the rest of the lathe to decide if it is worth keeping.
 
Thanks everyone for the advice. I have decided to look for a new lathe. The spindle bearings are the worst part, but the gearbox is pretty sloppy too, and there are a few other things that are showing wear.
 
I like to think there's a special place in hell for ops that abuse a machine like that. Wow...
 
Quick update. I looked at a few other machines but couldn't find anything I wanted. I did find another 10L locally, but it was in such rough shape I didn't even want to spend the $500 on it. So I decided to fix up this machine after all.

I bought a new (to me) loaded headstock, now I know what the bearings are supposed to look like! Also replaced the gearbox. I have been going through the rest of the machine, cleaning everything and replacing the felts. There is light wear throughout, but nothing as bad as the spindle bearings. About 0.007" wear on the ways and 0.035" play in the worm bushings. The half-nuts and the lead screw threads look fine.

Anyways I have one more question for you guys. I am going to sell off anything of value from the old headstock. Do you guys think the spindle is still usable? It doesn't look scored, but there are little iron bumps all over the journals. I don't really want to put it up for sale if it is just junk.
 








 
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