[Rich 72]

We had a spindle bearing failure on one of our takamaz x-10 lathes. I rebuilt the spindle as the manufacturer specified. My question is what is the best method for running in the bearings? I always thought it should be slow to start and increase the spindle rpm over several hours. Is this wrong?
Thanks
Rich

[RICHARD ZASTROW]

You might want to contact the manufacturers service dept.

Dick Z

[cam1]

What is the maximum RPM?
Precision bearings ie.spindle bearings typically do not require a run in, as they are manufactured to exacting tolerances. I do however recommend to allow the bearing to warm up at a low RPM, say 500RPM. I'd wait until the head warms up, and then gradually approach max spindle speed in 500 RPM increments, staying at each increment for a few minutes. The process of "break in" typically applies to greased bearings, where the object is to allow the grease to uniformly distribute itself ,and for the bearing to spit out the excess grease.Contrary to intuition, overgreasing precision bearings results in overheating, which allows the grease to run out of the bearing. The idea of a run in is to allow the bearing to reach operating temperature equilibrium.

regards

[ProductionPal]

Breaking in the spindle bearings properly is VERY important. Common sense will serve well enough. If you can get your hands on a thermal temp gun do it. Make a chart of rpms vs. temp vs. time. Start out at 200 rmp and slowly increase to say 500rpm over the course of an hour. Shut down and let the bearings completely cool(make take a couple of hours). Then starting out at 500rpm, run until thermal stability is reached for at least 15-30min before increasing to say 800rpm. Again, if you see the temperature stabilize for a half hour you can go ahead and increase rpms. If at any point temp keeps climbing at same rpm for more than 15-20min...shut down and let the bearings completely cool. This process is VERY time consuming. At any point you feel you should have acheived thermal stability and haven't, shut down again. This is repeated until thermal stability is reach at max rpm's. Operating temp is required info per mfg. spec

Others here may have better advice for you as far as rmp increments...