Main bearing induction hardened?

[jjbsa]

I remember reading a few years ago on a USA web page that some racers out there used to have hardened bearing steel (e.g. EN36 in UK grades) ring made up to be a press fit on a timing side shaft that had had its diameter reduced to take it.  I have tried more than once to find that page again but haven't been successful.  Does anyone still do this? 

[BSA_54A10]

I'm presuming that with 1k oil changes and running a return side paper filter I should get around 30k miles on my recently built motor. Is that sounding conservative?   

30,000 is the recommended rebuild intervals using BSA's recommended maintenance schedule and lubricants.
Modern luburicants will add at least 30% to that and changing your oil more frequently will extend it even further as will fittings an external oil oil filter.

I know a rider who got 80,000 miles out of an A65 with a dodgy main and it was almost in the same condition when he sold it.
He used to change his oil every time he returned from a ride. The oil was quite clean and went into his F150 truck after the Beesa had finished with it.

Now days, ring/bore wear should be the determining factor on rebuilds.