LOH LZ-25 Spindle Repair

The LOH LZ-25 is a very low speed grinding spindle.  It is grease lubricated, belt driven, and capable of running up to a whopping 50 rpm.

CHALLENGE

This LOH LZ-25 spindle was hard to turn incoming at our facility.  Upon disassembly and inspection, we noted that the interior of the spindle was contaminated.  We were surprised to find that the bearing complement does not include angular contact bearings, only thrust bearings and a linear ballcage.  The ballcage rides smoothly on the shaft after a good cleaning and lubrication.  The shaft was slighty worn but is fully functional.  The front housing ID had two deep wear grooves from a seal spinning.  Lastly, the front ID pilot was pitted and the shaft face had excessive runout.  No other dimensional deviations were noted for this repair.

SOLUTION

The following actions were performed on this LOH LZ-25 spindle:

• Clean, inspect overall dimensions
• Grind, chrome plate, and finish grind the front housing ID seal surface
• Replace thrust bearing balls and o-rings

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.