So why couldn't one replace that dumb ol' flat belt on an old lathe with
roller chain? I seem to remember that roller chain drives don't offer
perfectly smooth power transfer, but is it going to be a big deal? The
biggest loss, for me anyway, would be the loss of slippage when crashing
the carriage but the advantages of no slippage/shucking of the belt
under heavy load seem attractive.
My Logan 8" shaper is final chain drive. You can just discern the
pattern in the finish. It's still very good, but I wouldn't like it
on my lathe. When everything's right, the lathe finish is excellent.
Cause it would be noisy as hell, and speed changes would be time consuming
I have a large horizontal mill (7.5hp) that had a "silent chain" drive from
the motor to the countershaft. I needed to wear hearing protection when it
was running. I converted it to v-belts and now it's nice & quiet.
Base on personal experience it will eventually if not at first.
Roller chain is not a constant speed power transmitter except in one
case. That's when the exact same sprocket is used as the drive and the
driven. That's fine when everything's new. However the chain soon
wears just a little and there goes the smooth power transmission. The
resulting pulsations most definitely show up in the finish on lathe
work (don't ask how I know).