Duh,
My memory isn't always the greatest source of reference. Having just looked at a k75 and I'm on the same page.
Seems all hammers have to deal with side load, I would think the k75 less so with two guides. I've never had a hammer fail on account of that, just get sloppy , then adjust, shim, then replace. Course shimming a round bearing is really tough. I can't see how hardened ground shaft would prevent bearing wear any less, or are you expecting less deflection? I doubt the ka uses it,
Bob's too cheap, what's in Youngdylan's................mb