Babbit bearing questions

[Shawn scott]

I am restoring an Atlas 10f lathe that has the babbit bearing. When I pulled the bearing caps there were no shims and the bearing surface looks damaged to me. Does anyone know if there are acceptable gauge limits and are there alternatives to pouring new babbit metal? I have attached a few pictures of the bearing surface.

 

[pontiac428]

That looks like what you'd expect to see in any babbitt Atlas. The good news is your contact surface area looks reasonable, for what it is. The bad news is you are out of shims, meaning no adjustment is possible unless you do something rash like grind the saddles and caps. What you should do first is measure all degrees of spindle play in as-found condition. With these bearings, you can develop axial-vertical and axial-horizontal deflection because the cutting tool pushes up and back. So measure those deflections and see if you can live with them. If you can't, finding a Timken head will get you going. I'm not in the least bit interested in spending my weekends fumbling like Mr. Magoo pouring babbitt into an Atlas head. Disclaimer: I own a babbitt bearing Atlas with a little too much wear, and it does okay, except once in awhile, when it doesn't.

 

[markba633csi]

I don't know if it makes sense to try to re-babbit. Since the roller bearing headstock is such an improvement perhaps replacing with one of those would be the way to go?
-Mark

 

[Forty Niner]

In addition to the recommendation to do deflection checks, you may also gain information by doing some plastiguage clearance checks. And it might also be good to check the bearing contact with some Prussian blue.

 

[Shawn scott]

That looks like what you'd expect to see in any babbitt Atlas. The good news is your contact surface area looks reasonable, for what it is. The bad news is you are out of shims, meaning no adjustment is possible unless you do something rash like grind the saddles and caps. What you should do first is measure all degrees of spindle play in as-found condition. With these bearings, you can develop axial-vertical and axial-horizontal deflection because the cutting tool pushes up and back. So measure those deflections and see if you can live with them. If you can't, finding a Timken head will get you going. I'm not in the least bit interested in spending my weekends fumbling like Mr. Magoo pouring babbitt into an Atlas head. Disclaimer: I own a babbitt bearing Atlas with a little too much wear, and it does okay, except once in awhile, when it doesn't.

John,
Thanks for the advice and info. By feel there was no play in any direction, of course I will need to do the check again with a dial indicator . For now I think ill live with it and take your advice and start looking for a Timken bearing head.

 

[craniac]

I would definitely measure the run-out before concluding that you need a new head. My 1937 Atlas has only a few tenths run-out at the spindle using babbit bearings.

Might be a minority opinion but I think babbit might be superior- it's just that ball bearings are so much cheaper and low maintenance. They do require lubrication though, but none of us here neglect oiling their lathes I'm sure.

Tim

 

[wa5cab]

I would also recommend replacing the babbit bearing headstock with the Timken one. Note that besides the headstock casting itself, the original spindle is part # 10-31. The Timken spindle is 10-31T and they are not interchangeable. However, most of the parts loaded onto the spindle are interchangeable. So if you do purchase a complete Timken headstock, compare the two sets of parts and use the better one in each case.

And BTW, Atlas only ever built one metal-working lathe (or two if you count the 101.21200 separately) with ball bearings, and that was the 3950, first version of the 6" Mk2.