Bill Dufour
01-21-2023, 4:15 PM
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 cross hole in the shaft for a cotter key?
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
I do not know the age but the cord is grounded with a two prong plug and. seperate ground clip. I am guessing early 1960's or older
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 cross hole in the shaft for a cotter key?
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
I do not know the age but the cord is grounded with a two prong plug and. seperate ground clip. I am guessing early 1960's or older