just a quick one about the 1-1/4-inch 1/4-inch shank bit flush trim bit with top and bottom bearings that gets unruly at full revs.
took off the end bearing and allen screw rev'd up to 23,000rpm and no problem
with bearing back on all hell breaks loose
my guess is that the ball-bearings are piling up on one side and cause things to get eccentric
I may try some bearing swapping if I'm really bored