A hammer drill comprises a drive mechanism including a spindle, a first ratchet coupled for co-rotation with the spindle, a second ratchet rotationally fixed to the housing, and a hammer lockout mechanism adjustable between a first mode and a second mode. The hammer drill further comprises a clutch adjustable between a first mode and a second mode. The hammer drill further comprises a detent radially movable between a locking position and an unlocking position, and a collar movable between a first rotational position in which the hammer lockout mechanism is in the first mode and a second rotational position in which the hammer lockout mechanism is in the second mode. In the first mode the detent is positioned such that the spindle is moveable relative to the housing. In the second mode the detent is positioned such that the spindle is prevented from moving relative to the housing.