When polishing a bore to finished size, old abrasive flap-wheel edges can load up and stop cutting. To remedy the problem, I touch the rotating flap wheel on its driving tool to a pedestal grinder's rotating wheel. The grinding wheel removes enough of the flap-wheel diameter to expose fresh abrasive edges. As a warning, it is extremely important that the flap wheel and grinding wheel rotate in the same clockwise direction. The leading edges of the flap wheel should turn away from the grinding wheel.
Thomas Sveda, Charleroi, Pa.