We received the Makino J-3 Spindle with the complaint of high noise along with vibrations. Also the reported runout on a 200 mm test mandrel was more than 300 micron. The spindle was dismantled and all the components were cleaned. Bearing condition was found to be absolutely dismal. 

Ground the spindle nose within the accuracy of 1 micron. All the rotating components were dynamically balanced. Then Spindle was re-assembled. Checked the runout which was 1 micron on the spindle nose and 6 micron on a test mandrel of 200 mm length.