Was the .125"BN a Tapered? Or did a standard BN manage that 2XDiameter initial cut OK?
I'm always way to cautious on pass depths. But just getting into 3D so my BN bits are really limited and virtually never do mid or big size stuff and it's good to know. Still using engraving bits here for my teeny stuff because detail is better even than a 1/64"BN and I can do no roughing cuts on the dished buttons.(and 64'ths scare me)
(Sharpies? Going to have to scope that out...thanks!)