Abstract: A power tool includes a housing, an output shaft supported by the housing for rotation about an axis, a battery terminal selectively operable to receive a DC power supply from a battery, and a receptacle selectively operable to receive an AC power supply from an AC power source. The power tool further includes a motor operable in a first power mode, in response to receipt of the DC power supply, to rotatably drive the output shaft, and also operable in a second power mode, in response to receipt of the AC power supply, to rotatably drive the output shaft. The power tool also includes a mechanical interlock movable between a first position in which the interlock inhibits the flow of the AC power supply to the motor and a second position in which the interlock inhibits the flow of the DC power supply to the motor.