Abstract: The drill includes the usual tool spindle driven by reversible motor, and conventional chucking jaws which rotate with the spindle. The jaws are surrounded by an actuator which is drivingly connected to the jaws, and normally rotates with the jaws when the drill is in use. A manually operable control member on the housing is movable between two operating positions in each of which it holds the actuator against rotation, and consequently causes the spindle to move the jaws to bit-locking or bit-releasing positions, depending upon the direction or rotation of the spindle. Whenever the control member is moved from one to the other of its positions it switches the direction of rotation of the motor.