Dear All, I have done this successfully on an old pitted headset. Only good
for an occasional rider as you will wear away the hardened surface to take out
the pits. It's only microns thick.
I used valve grinding paste from an auto repair shop. I held the cup in the
lathe chuck smeared it with the paste and stuck a load of balls to it. Then
the race was offered up on the running centre. A slow speed ,about 180rpm and
moderate pressure was used. I kept undoing it all and cleaning out the black
goo to check on progress. I also ran the lathe backwards and forwards. I guess
on 5 -6 applications of paste before it looked uniform. I wont say smooth
'cause it wasn't. It looked dull grey but with no pits.
Re Lawrence's enquiry about grey/black patches. If no rust is visible and
it feels smooth then I would'nt worry too much. Mark Stevens. London