[sanddrag]

Support your shaft with your wheel or whatever it is on its own. Put half of a flex coupling (lovejoy makes good ones) on the end of it with a keyway and key for transfering torque and perhaps a set screw to prevent axial movement. Put the other half of a flex coupling threaded onto the drill gearbox output shaft. Hold it on with a left hand screw and washer. Put a flex copuling spider (insert) in between. Put the two together. Mount the drill.