We do not recommend using the NAPA undersize pilot bushing, as the auto cranks were drilled (not bored) and the undersize bushing will not be centered properly in the crankshaft. The correct way to use an auto crank is to set it up off the side of your mill, tram the flywheel register to make sure you are centered properly, and use a boring tool to open up for the standard .940 bushing----or just use the roller bearing.