I've noticed recently that my BT30 tooling has been showing signs of fretting on the taper. I'm not sure if this is because of increased production/use or because I've been more aggressive with the tooling. My favorite end mill is the IMCO 1/2" 2 flute streaker which, depending on the program, could be cutting up to 0.5" depth and full width through 6061-T6 aluminum. The spindle barely even loads up and the DM4400 seems to not even notice. Tool holders with drills or boring heads show no sign of this whatsoever, just the end mill holders.

Perhaps the Belleville washers are getting weak...

Is this happening to anyone else?

Timothy