Hmmm, looking at the specs for ball bearings I can say it will work, but...as usual there's a but. The shaft goes through two ball bearings, one in the middle, one on the end. I was thinking resting the middle bearing on a circlip and locking the end one with a cap via a bolt. The main idea is to have zero axial play on the shaft, so the dimensions of the shaft and the space between the bearings need to be spot on, super precise, otherwise I get play or I preload the bearings, neither of which is good. Anyone knows of any ideas on how to solve this?

Taper rollers don't have this problem as you need preload anyway, which then takes care of any axial play.

Regards,
dsc.