Abstract: The preferred embodiment can be incorporated into a powered instrument which rotates a tool. The preferred embodiment permits changing the direction of rotation of the tool without using the hand that does not grip the instrument housing to operate the tool, and without altering the grip on the instrument. The preferred embodiment includes an actuator which moves between two positions to selectively couple two rotating members to an output shaft. The output shaft is rotated in one direction when one rotating member is coupled to the shaft and is rotated in the remaining direction when the remaining rotating member is coupled to the shaft. Movement of the actuator between its two operative positions can be achieved by pushing on the instrument housing to push the tool against the workpiece, or by pulling the instrument housing away from the chuck if the tool is embedded within the workpiece.