Nobody's agonizing. As already stated, the necessary correction in grinding shops has been made. Answers like "just run it at an angle because it's a South Bend" (I'm paraphrasing here) aren't answers to the questions that were asked.
It's a machine rebuilding/engineering question: How much deviation is too much deviation for a plain bearing oil film to function as intended?
A rebuilder just has to work with such specs as he can hire from a specialist - your TWO grind shops - or do for himself. Can't shit what was never on the menu to eat.
Might "Timesaver" work for you? Or do you need a different abrasive for your Chromed goods? Above my current Pay Grade, but someone here will know.
Otherwise, the THEORY was in a formal course, ME-something-or-other, 1960's. Go and sit the course if the
academics of it matters to you more than what the SB can deliver.
I'm sure it has been updated to cover the advances in lubricants and the wider variety of bearing materials - easily a hundred and more times more choices than were available, dawn of the 1960's. Lead-Indium, to name one, was already over 20 years and more in widespread use, but not covered at all in the theory at the time. Bronze or Babbitt against hardened steel were good enough "for training purposes". There would have been advanced courses and post-graduate courses.
I wasn't even in an ME program. EE, rather. This was just a useful subject, all-around, a no-effort "A". One of TWO "A" that semester, so maybe not so "no-effort" if one was not already a reasonably well-experienced machinist & mechanic. Credits were credits. Actual "learning" had little to do with Universities, then, and even less-so, NOW. They are merely in the money-lender business.
Nothing wrong with "knowing".
The hard part is the
sweat required to get a hobby lathe to actually give a damn about what
you know! They may have "ears" on various bits of kit for mounting stuff, but they still don't LISTEN very well!
