Automatic drill press motor balancer

Automatic balancer to get rid of motor vibrations caused by shaft weight imbalance.
I used an old 40mm outer diameter ball bearing after I cleaned out the remaining grease and dissembled it. The outer race and balls still had mirror finishes and this affects how well this mechanism balances.

Press the outer race into the printed part and slip it on the vertical drill press motor shaft, everything must be a tight fit. It is important that the outer race be axially centered on the shaft or it won't reduce vibrations. Put several balls into the race but keep it less than half full. I also positioned the motor pulley to prevent any balls from falling out. At motor spin up the balls roll to locations that center the outer bearing race. Do not use lubrication as it stops the balls from rolling freely. This mechanism will only properly balance a motor if the balls have sufficient weight for the task.

This is an old balancing concept. I first saw this used in high speed CD rom readers.