[lrgoodger]

I've been researching ballscrew thrust bearings non-stop since my previous post and I have learned a ton. I learned that new ones are too expensive for a retired hobbyist on a fixed income like me. I have discovered the answer to most of the questions in my previous post, so now the question is changed.

Since I already have zero backlash on both X and Y axes, the only reason for replacing these bearings is that I can feel that they are in distress (feel 'gritty' when turning by hand) and would likely not last long under regular use (which I won't do anyway). I think the Y axis would last as long as I will, so I'm not going to do anything with it. The X, however, is very gritty and may not last long at all, so I want to do something with it while I have the machine disassembled. In other bearing applications where they were un-shielded or had a removable shield, I have flushed out the gritty debris in them and had them perform fine afterward. This prompts new questions.

First, do the 3M9110W1H X axis bearings have removable dust covers? I discovered that the spindle bearings do when I went through the head (but I don't know about the Z axis thrust bearings since I didn't remove them, thank goodness).

Second, presuming I can successfully wash out the bearings, how do I get the preload back to where it is now? The fact that the bearing nut is staked on is going to require a lot more torque to remove it than what the preload alone would require, so I can't just measure removal torque and re-torque to that same value. I feel if I do that, I will have too much preload.

If I bite the bullet and get new X axis bearings, how would I know how much to torque them to set the preload?

Ron

[lrgoodger]

I kept on searching and reading and found the answer to the preload question. It seems for these bearings that preload is ground in during manufacturing. Now all I have to do is get that lock-nut off and see if I can clean them out!

Thanks for answering all my questions guys (the answers were all in previous posts).

Ron

[williamtraughbe]

I've been researching ballscrew thrust bearings non-stop since my previous post and I have learned a ton. I learned that new ones are too expensive for a retired hobbyist on a fixed income like me. I have discovered the answer to most of the questions in my previous post, so now the question is changed.

Since I already have zero backlash on both X and Y axes, the only reason for replacing these bearings is that I can feel that they are in distress (feel 'gritty' when turning by hand) and would likely not last long under regular use (which I won't do anyway). I think the Y axis would last as long as I will, so I'm not going to do anything with it. The X, however, is very gritty and may not last long at all, so I want to do something with it while I have the machine disassembled. In other bearing applications where they were un-shielded or had a removable shield, I have flushed out the gritty debris in them and had them perform fine afterward. This prompts new questions.

First, do the 3M9110W1H X axis bearings have removable dust covers? I discovered that the spindle bearings do when I went through the head (but I don't know about the Z axis thrust bearings since I didn't remove them, thank goodness).

Second, presuming I can successfully wash out the bearings, how do I get the preload back to where it is now? The fact that the bearing nut is staked on is going to require a lot more torque to remove it than what the preload alone would require, so I can't just measure removal torque and re-torque to that same value. I feel if I do that, I will have too much preload.

If I bite the bullet and get new X axis bearings, how would I know how much to torque them to set the preload?

Ron

Ron,
You may be over thinking this. Just go by the bearing manufacture's recomendation. Old bearings that feel gritty, Idk. Clean them, put good grease, hope for the best. If your not machining very precise tools it may not matter.