Diamond Finishing Kit?
P4039

For the slickest spin, give your axles an ultimate mirror-finish!
Equivalent to an 8000-grit finish, this specially formulated
diamond compound removes the finest axle and hub imperfections
and scuffs. Use as the final finish to a progressive polish with
the Micro-Polishing System? (P4038).
Works with one-piece and nail-type axles
Kit contains enough material to finish axles and hubs for five
racers.