HSD ES789 Spindle Repair

HSD is a very popular spindle manufacturer that a lot of machine tool OEM’s use in their machines.  This HSD ES789 spindle is grease lubricated, stator driven, and capable of running up to 24,000 RPM.

CHALLENGE

Our customer sent in this HSD ES789 spindle stating that the bullet to the grippers was loose and they were having sensor issues.  Once the spindle arrived at Northland Tool we noted right away that one of the fingers to the gripper was broken.  We then completed a full breakdown of the spindle and recorded that the grease in the rear bearings had turned brown from fretting of the bearings and housing.  The #2 proximity sensor was positioned incorrectly but passed bench testing along with the others.  The rear shaft nut was difficult to remove and received damage that will need to be repaired.  We then performed a full dimensional inspection of the spindle.  We found that the HSK 50 taper had high run out with poor tool contact and the front shoulder had high run out.

SOLUTION

The following actions were performed on this HSD ES789 spindle:

• Clean, inspect overall dimensions
• Replace bearings, bolts, o-rings, and grippers
• Grind, plate, grind (GPG) the HSK 50 taper
• Kiss grind the front bearing shoulder
• Weld and repair damaged shaft nut

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.