Northland Tool Blog
Walter DB112005 Spindle Repair

Walter DB112005 Spindle Repair

Our customer, a large tooling manufacturer, was experiencing a loud, roaring noise and poor part finish with this double-ended grinding spindle. Our evaluation of the spindle showed that one of the two pairs of ceramic bearings had failed due to contamination with grinding swarf. The grease in those bearings was degraded to a dry powder, providing little or no lubrication. We also determined that the wheel hub tapers on both sides had excessive runout.

CHALLENGE

Walter DB112005, 10,000 RPM, grease lubrication, belt drive, dual OD tapers for wheel hubs

Our customer, a large tooling manufacturer, was experiencing a loud, roaring noise and poor part finish with this double-ended grinding spindle. Our evaluation of the spindle showed that one of the two pairs of ceramic bearings had failed due to contamination with grinding swarf. The grease in those bearings was degraded to a dry powder, providing little or no lubrication. We also determined that the wheel hub tapers on both sides had excessive runout.

SOLUTION

We replaced both sets of ceramic bearings and improved the runout of both tapers with a kiss grind on one of our own Kellenberger cylindrical grinders, which can hold micron tolerances. Once rebuilt the tapers had less than a micron of run out. The spindle was completely broken in up to full speed on our specially made test stand. The Walter spindle passed our stringent quality standards and was shipped to our customer.

RESULT

The spindle was installed immediately by our customer. Our follow up call found it running as good as new and making perfect parts.

DETAILED CAUSE OF FAILURE

  • Dry grease residue on the side that did not fail catastrophically.

  • This is the housing from the side that the bearings failed. The black powder is a combination of phenolic cage, contamination and grease. Once the grease deteriorates the balls contact the phenolic cage causing more debris that causes the rolling elements to fail.