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Old 07-14-21, 03:57 AM
  #79  
oneclick 
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Originally Posted by 3alarmer View Post
Polishing doesn't take off much surface, but when something is pitted deeply enough that you need to remove the surface to some depth to get rid of the pits, you may or may not be going past the hardened surface. Which may or may not affect overall longevity in further use. I've never studied it in depth.
It's not the going through the case that is the problem, it's that a ball-bearing needs accurate sizing and concentricity as well as a pretty-looking surface. Grade 25 balls are (supposed to be) within one ten-thousandth of an inch of the correct size. When a pit is big enough to see with a 3x or 5x loupe it's deeper than that. To grind a new race as deep as the deepest pit and maintain concentricity and accuracy is NOT something you want to try to do hand-held.

A race that is not the same diameter or is not concentric within that ten-thousandth will mean that some of the balls are not touching the races; they bear zero load at that point. You may only have eight or nine balls in the bearing, lose contact with any of them and the load on the remainder goes up - and so even if there's any case left a ball will soon punch through it.

Last edited by oneclick; 01-12-22 at 01:48 PM.
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