Well I was beginning to think my spindle bearing was going south, it was making strange noises. Then I started up the machine and thought that I forgot to raise the Z axis because I heard a cutting sound. I hit the E stop and checked, nope all clear. Further inspection revealed that the spindle nut set screw had come loose and was hitting the safety cap. Now the nut itself was also loose. I tightened it but i'm afraid I may have over tightened it! How tight should it be?? The spindle stops spinning almost imediately after hitting the E stop. Is this to tight?? Also prior to all this drama I noticed that the spindle was getting hot during extended use is this normal?

Robert Willis

Consult your owners manual for any bearing preload recommendations.

Yes, you could have tightened it too much. If you haven't a clue from the manual, you can tighten it until you JUST start to feel drag. Not tight drag, a SLIGHT drag.

Bearings do run warm as they reach operating temp, thge longer you run them the more temp they will stabilize at.

How hot is hot???? As in a temp number. Not a nebulous warm, hot, scorching describer. 120 to 150F would not be an excessive temp. Depeding on the preload factor prescribed by the manufacturer, you might eve go to 160 or 180F but no higher.

Much over 180F and grease life starts to plummet from the heat.

thanks for the input. i checked the manual but the is no preload recomendation :-( Tanks again for the advice.


Robert Willis