Every application is different. And this was a thread about "rule of thumb." So, no amount of friendly chat here can begin to be an education on bearings, gearboxes, oil reservoirs, gear grinds and how all affects heat... as alluded to in previous posts.
I just gave my $0.02 worth. I've been repairing and building machine tools since before there even was a CNC. I've spent my entire life at it, not just dabbling here and there. The important thing for me is that I know I'm still learning.
I suggest when setting used bearings: Go lighter on preload than your application would call for when new. If your application calls for clearance, keep the same clearance. Expect gearbox oil splash to take away bearing heat to a great degree. If it can't run cool, something is wrong somewhere and may or not be part of a poor design. Break in can cause a LOT of heat, or in some setups will cause very little heat. Different setups are different.
Your lathe is pretty basic. Just tighten until your deflection is OK. You'll never get rid of it all, If warm, loosen it again. If you still have problems, maybe new bearings?
I just gave my $0.02 worth. I've been repairing and building machine tools since before there even was a CNC. I've spent my entire life at it, not just dabbling here and there. The important thing for me is that I know I'm still learning.
I suggest when setting used bearings: Go lighter on preload than your application would call for when new. If your application calls for clearance, keep the same clearance. Expect gearbox oil splash to take away bearing heat to a great degree. If it can't run cool, something is wrong somewhere and may or not be part of a poor design. Break in can cause a LOT of heat, or in some setups will cause very little heat. Different setups are different.
Your lathe is pretty basic. Just tighten until your deflection is OK. You'll never get rid of it all, If warm, loosen it again. If you still have problems, maybe new bearings?