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Cat40 spindle rebuild: Thoughts on floating bearings outer races spinning in housing

Fairly certain they are in a DF face to face arrangment. That's the only way they can work
Yes, I also thought that DF would be the only option, but I decided to ask the author of the topic - it’s better to be safe :)
Has any one here ever welcomed you? Might be difficult in these times with the Ukraine situation. But if you are here babbling about spindle bearings. That just makes you another industrial gypsie / brother. I had no say on where I was born.
Thank you! No one on this forum has ever attacked me because of where I live. Except for another dude from Russia)))) But let’s not talk about that here, it wasn’t enough to bring politics into this section.
 
In the late 70's I worked for a physicist. Quite a character, in his 80's then. He had many stories about the China Lake research facility during WW2.

He did lots of gyroscope research and design. These very cool things would fit in your hand, and used tiny precision bearings. He knew a lot about bearings and invoked the static vs. sliding friction argument. He confessed sometimes for prototypes they would upset the sliding bearing bore with the point of a scriber if they missed they very small bore tolerance.

If the size of your bore is in the correct place just go with it. Bearing design is long time tested. I don't recall any bearing design manual advocating worry about properly fitted bearings and race creap. But they all caution against failure to allow for axial bearing movement.
 
I did the run in procedure yesterday. It was interesting looking at the visible part of the spindle cartridge (directly outside the lower bearings) with a thermal camera. I could distinctly see that the single bearing in the triplex set was warmer than the other two. But after the run in the temperature stabilized nicely, and didn't go up any more after a good long run at max RPM. The part housing the bearings I was worried about is inside the head casting, but I couldn't hear any evidence of them spinning with a stethoscope.
 
99% of electric motors housings are a clearance fit.
24/7 operation for years before they are wearing grooves into their housing. Some decades.
Seen thousands of them.
I would not be concerned at all. Check run out. Check deflection. Check for looseness at the spindle.

What do you expect of the machine?
You are rebuilding yourself, not buying a new kern. Different expectations.
As always monitor the machine over time.
 
99% of electric motors housings are a clearance fit.
24/7 operation for years before they are wearing grooves into their housing. Some decades.
Seen thousands of them.
I would not be concerned at all. Check run out. Check deflection. Check for looseness at the spindle.

What do you expect of the machine?
You are rebuilding yourself, not buying a new kern. Different expectations.
As always monitor the machine over time.
Actually in the electric motor world it was desirable to have the race spin at a rate of 1 rev/million shaft revs (or something like that. Don’t have the book open right now)
This assisted uneven wear on the race from directional loading
 
Actually in the electric motor world it was desirable to have the race spin at a rate of 1 rev/million shaft revs (or something like that. Don’t have the book open right now)
This assisted uneven wear on the race from directional loading
Now that is interesting. I would read that book.
 
Now that is interesting. I would read that book.

Take a peek at this one.
Bear in mind it’s like the machinist handbook wherein it gets revised and sometimes changes wording or co tend as it evolves.
(Old machinist handbooks had lots of data on wood, sadly not anymore)

 








 
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