Abstract: An adaptor for a hand-operated power machine tool, such as a power screwdriver, comprises a sleeve adapted to receive a cutting tool bit in the forward end and an aperture for slidably engaging the shank of the screwdriver bit in the rearward end. The sleeve preferably also comprises a concentric bearing-mounted grip allowing free relative motion between the grip and the sleeve. The adaptor is used for performing a series of operations where a guide cutting is first made in a workpiece, and then a screw is driven into the guide hole.