[Milsurplus] Wanted.

[J. Forster]

>  I've always wanted to ask/know how ball bearings are made... always seems  a
> bit like those Chinese puzzles how they get the balls/rollers inside and with
> such a fine tolerance so they don't rattle about and come out.

The inner and outer races are ground to size, as are the balls. Grinding to
0.000050  is quite easy with decent machinery. Many bearings have a ball
retainer which spaces the balls. The bearings are loaded with the balls on one
side and then the balls are spaced out, the retainer inserted. Some have no
retainer and are just snapped together, possibly with heating or cooling of the
races.
-John