I pretty much found my issue, Im sure some others will be the same. when using a drill or a motor attached to the shaft, any pressure on that shaft up down left or right can put stress on the bearings or bushings. over time that pressure will wear them out, my drill was mounted on plywood and the mill was too, the shim I used was just a piece of plywood I had and not perfectly lined up, may be a 1/16 of an inch off " but just enough to wear on the bearings and 3 years later they just gave out. the same thing can happen to a drill attached to the shaft hanging in the air, lots of pressure in the wrong direction, eventually it will wear out
