At 10:13 PM 12/10/2000 -0500, Lawrence Kurtz wrote:
>Can bearing rolling surfaces showing wear from years of use be polished or
>should they be left alone, assuming little or no pitting. If so is there
>a procedure for using equipment such as using a Dremel. Materials in
>question are old Campy Gran Sport. I guess I'm wondering whether I should
>be concerned about dark oxidation blotches in the hubs, races etc.
For whatever it's worth, I'll share my thoughts, and what I want to do,
hoping that exposure to light will dispel my own ignorance.
1) The difference between good and great cones and races is surface finish. I'm convinced that the old campy record stuff was polished (abrasive finished) instead of being finished "as well as possible" with a lathe-like cutting tool (as on the lesser Normandy hubs).
2) This suggests that a worn cup and race could be improved by polishing out. I'm planning to try doing this with a specific bottom bracket, by using sequentially finer grinding compounds. I can mount the spindle in my drill press, and the cup can be clamped down on the bed. I will use water and grit for the cutting, with 1/4" balls. I assume that I will sacrifice some balls as they wear down in the grinding process, otherwise I'll wind up with small balls and the wrong curvatures on the faces.
3) Now, back to the original question: Given how little of the actual friction of a bike comes from the bearings, I don't think that a rider can tell the difference when riding. A nut like me could tell the difference while spinning the bits at the bench, of course, so it's woth doing for this kind of esthetic.
4) The one for which I plan to try it is desperation-driven: Old French stuff with significant pitting. "Can this spindle be saved?"
Anyone have good ideas on where to get grinding powder? Probably a glass-working shop for the small quantities I need.
PS: I don't think one could make a living doing this!
Harvey Sachs
McLean Va