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There is hole on this old electric motor Should I use oil or grease for it?
Can you open the motor and determine what type of bearing?
What does it have on the drive end?
In the absence of other information I would guess one drop of oil.
It may be a graphite impregnated bronze bearing in which case a drop of oil will extend the life of the bearing.
The solution to bearing failure in these small motors is replacement of the entire motor.