If you have a small part made out of harden to steel rc 65-70 that needs to be lapped on a face, Id and od to a tolerance of .00002 how much oversize should the part be ground to? Yes millionths not tenths.
The part would be a OD.500 X ID .125 X Length .75
It would be inspected using light wave bands for flatness and air gages for the diameters. The lot sizes would be 10 pieces at a time.