Stama NN3011-234411-40M Mostly just contamination-induced failure
Stama NN3011-234411-40M, 5100 RPM, grease lubrication, coupling driven
This spindle came to us from an automotive brake system manufacturer because it was faulting out the drive. Small wonder, as we could feel that the bearings were obviously in very poor condition when rotated by hand in assembly incoming. Upon disassembly, we discovered that the grease in the bearings was severely degraded from contamination with a fine black particulate, especially in the front of the spindle.
Fortunately for our customer, we did not find any significant dimensional deviations of the shaft or housing. We proceeded to rebuild the spindle with all new bearings, HSK gripper seal, o-rings and assembly screws. We finished this straight rebuild with our final test run, break-in and final QC. This spindle was one of four that were sent to us at once. Only one of the four required any dimensional work, a grind, chrome plate & finish grind to correct excessive runout in the HSK63 taper.