A power tool comprising: a housing; a motor supported by the housing and including a motor shaft; a spindle supported by the housing to turn about an axis, the spindle being selectively turned by the motor about the axis in first and second opposing directions; a first locking member (26a, 26b); a second locking member movable between a locked position, in which the second locking member engages the first locking member to prevent rotation of the spindle, and an unlocked position; a transmission for transmitting torque between the motor shaft and the spindle, the transmission including an inner rotor and an outer rotor that is mounted substantially about the inner rotor, the inner and outer rotors being mounted coaxially and for limited rotation relative to one another; at least one pair of recesses (40, 41), comprising first and second recesses provided on one of the inner and outer rotors, at least one spring and at least one projection provided on the other of the inner and outer rotors, each projection being biased by the spring into a selected one of the first recess and the second recess, the springs being operable to delay movement of the second locking member from the unlocked position to the locked position when a force is applied to the spindle to cause the spindle to rotate relative to the motor shaft; whereby, when the spindle is rotated in the first direction relative to the motor shaft, each projection is movable between a first position, which corresponds to the unlocked position of the second locking member and in which each projection is positioned in the first recess, and a second position, in which each projection is positioned in the second recess, movement of each projection from the first recess delaying movement of the second locking member from the unlocked position to the locked position; and whereby, when the spindle is rotated in the second direction relative to the motor shaft, each projection is movable between the second position, which corresponds to the unlocked position of the second locking member and in which each projection is positioned in the second recess, and the first position, in which each projection is positioned in the first recess, movement of each projection from the second recess delaying movement of the second locking member from the unlocked position to the locked position, and wherein the first and second recesses (40, 41) are circumferentially spaced apart in an outer surface of the inner rotor and the projections extend from an inner surface of the outer rotor. a housing; a motor supported by the housing and including a motor shaft; a spindle supported by the housing to turn about an axis, the spindle being selectively turned by the motor about the axis in first and second opposing directions; a first locking member (26a, 26b); a second locking member movable between a locked position, in which the second locking member engages the first locking member to prevent rotation of the spindle, and an unlocked position; a transmission for transmitting torque between the motor shaft and the spindle, the transmission including an inner rotor and an outer rotor that is mounted substantially about the inner rotor, the inner and outer rotors being mounted coaxially and for limited rotation relative to one another; at least one pair of recesses (40, 41), comprising first and second recesses provided on one of the inner and outer rotors, at least one spring and at least one projection provided on the other of the inner and outer rotors, each projection being biased by the spring into a selected one of the first recess and the second recess, the springs being operable to delay movement of the second locking member from the unlocked position to the locked position when a force is applied to the spindle to cause the spindle to rotate relative to the motor shaft; whereby, when the spindle is rotated in the first direction relative to the motor shaft, each projection is movable between a first position, which corresponds to the unlocked position of the second locking member and in which each projection is positioned in the first recess, and a second position, in which each projection is positioned in the second recess, movement of each projection from the first recess delaying movement of the second locking member from the unlocked position to the locked position; and whereby, when the spindle is rotated in the second direction relative to the motor shaft, each projection is movable between the second position, which corresponds to the unlocked position of the second locking member and in which each projection is positioned in the second recess, and the first position, in which each projection is positioned in the first recess, movement of each projection from the second recess delaying movement of the second locking member from the unlocked position to the locked position, and wherein the first and second recesses (40, 41) are circumferentially spaced apart in an outer surface of the inner rotor and the projections extend from an inner surface of the outer rotor.