Hwacheon Lathe Spindle Repair

CHALLENGE

Our customer sent this turning center spindle in for rebuild because of poor part finish and excessive bearing noise. The front tapered roller bearing failed from contamination with coolant, which had washed out almost all of the grease and allowed corrosion of the rolling elements and raceways. The contaminant had also largely displaced the grease in the rest of the bearing complement, including the rear tapered roller. Our dimensional inspection also showed slight damage on the tooling taper OD and face. We did notice that both the front and rear housing IDs were on the loose side of ISO, but there was no fretting which would indicate that this condition contributed to the bearing failure. As the housing bores were likely manufactured this way, we did not recommend grind, plate & finish grind to tighten them up.

SOLUTION

The following actions were performed on this Hwacheon Lathe spindle:

• Clean all parts of the spindle
• Replace all bolts and o-rings
• Replace bearings
• Kiss grind taper OD and face

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.