Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
I bought an older grinder for a powermatic 18" planer older. The motor bearings seem to be okay. Hard to say with a universal motor with brushes. The spindle needs new bearings they feel and sound crunchy. I can not read any bearing numbers due to heavy factory green paint. Since it is belted down from 10,000 rpm at the motor I assume I can use rubber sealed bearings. The rpm is probably under 3000.
The arbor is odd. I see nothing holding in the bearings, no snap rings, probably just a tight push fit. I also see nothing holding the spindle shaft in the bearings. It looks like a straight shaft just pushed in. Nothing obvious stopping it from coming off the end. There is no axial load to speak of so they. may have let it float a bit? The belt will prevent it from moving far. It does have a small cross hole in the shaft for a cotter key perhaps.
I know for a tool post grinder they need high quality bearings with very little runout. How critical should these be. I assume better then the average motor quality stiff sold everywhere?
Bill D
looks to be two 9101 bearings on the spindle. I was able to find two exact replacements on the bay.
The arbor is odd. I see nothing holding in the bearings, no snap rings, probably just a tight push fit. I also see nothing holding the spindle shaft in the bearings. It looks like a straight shaft just pushed in. Nothing obvious stopping it from coming off the end. There is no axial load to speak of so they. may have let it float a bit? The belt will prevent it from moving far. It does have a small cross hole in the shaft for a cotter key perhaps.
I know for a tool post grinder they need high quality bearings with very little runout. How critical should these be. I assume better then the average motor quality stiff sold everywhere?
Bill D
looks to be two 9101 bearings on the spindle. I was able to find two exact replacements on the bay.
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