From memory: there are no steps in the BB shell, just circlips (with corresponding stress inducing grooves) on the axle to keep everything in place. The tightest fit should be on the axle so I would press the bearings in together with the axle. Use something to push on the bearing with a hole, something like a used RH BB cup should work -- mvg
Marten Gerritsen
Kiel Windeweer
Netherlands