Hardened Lathe Bearings Refurbishment

Your bearings look to be in pretty good shape. But I would pay special attention to the area where the two tapers meet to be sure there is no binding there - quite often there is a relief cut into the bearing there.

dave8

Edited By david bennett 8 on 13/06/2023 11:12:52

Edited By david bennett 8 on 13/06/2023 11:15:02

Personally, would be VERY wary of abrading anything too much.

In the extreme the hardend case could be penetrated / removed., which defeats the whole purpose.

I would put my money on the hydrodymaic lubricatiom. Possibly using an Extreme Pressure oil to maintain the oil film.

Although such lubricants tend to contain sulphur, there are no yellow metal bushes that would suffer, and although high viscosity, the effect will become less as the temperature rises.

Try not to fix anything that is not badly broken!

Howard

Howard, these bearings are normally through-hardened, not case-hardened.

dave8

I'll bow to superiorv knowledge.

Bearing bushes, yes, but a relatively big shaft say 1" diameter?

Howardi

You might well be right. I was thinking of the bushes. The area of concern here is one that is often relieved so a loss of hardness where there should be no contact doesn't matter, but you are right to warn care is needed.

dave8

Well, after considering Howard Lewis' point, I realised I didn't know if large (relatively) lathe spindles were through hardened or case hardened,or something else. After a bit of research, it is still unclear - it could be either. It is quite reasonable to through-harden a hollow spindle of this size. From what I have seen, this is the most likely in a high-end lathe like this, but some form of selective hardening may have been chosen.

dave8

A huge thanks for all your input on these. I think the take away is to maybe just double check for binding where the two tapers meet, address this issue with a very light stoning if needs be, but then await trials and testing to see if there are actually any serious issues.

This is what I will do.

Thanks again,

James