When working at small dia's the necessary rpm has my gear train just screaming. They howl so bad my family shuts the door to hear the TV. I realize they're straight cut gears and ain't never gonna be dead quiet, but I went poking around in there anyway.
As a typical example, my tumbler gear bushings are out to .628-.629 and the shafts they ride on are .622 or so. Cheap and easy would be standard replacement .625 bushings but I wouldn't be adverse to making my own custom fit bushings to what's left of the shafts.
Is this a worthwhile idea? If so, what clearance should I use?