Dirty Ern and others,
Since you can get 1.0mm(0.040")undersize bearings, the crank must be hardened that deep. I have only gone to that size once. That was on a 1958 or 1959 190a. It worked just fine. No problems.
Ern. Are you really dirty?
Bill Lewallen;Lexington,Ky.
Home of Valvoline oil- Maker of the now orange colored MB antifreeze, and Zerex, also orange.???