A multi-mode hammer drill comprising: a support member having a shift surface; a shift member mounted on a support member in a configuration permitting movement along the shift surface of the support member between a first mode position corresponding to a first mode of operation and a second mode position corresponding to a second mode of operation; characterized by: the support member having a lock surface; the shift member having a cooperating lock surface, and the shift member being further mounted on the support member in a configuration permitting movement, when the shift member is in the first position, between a lock position where the lock surface can engage against the cooperating lock surface, and an unlock position where the lock surface cannot engage against the cooperating lock surface; a biasing member configured to exert a locking force on the shift member toward the lock position; an actuation member coupled to the shift member in a configuration that, during shifting between the first mode of operation and the second mode of operation, generates an unlocking force sufficient to overcome the locking force and to move the shift member to the unlock position, and thereafter, the actuation member moving the shift member along the shift surface of the support member from the first mode position to the second mode position. a support member having a shift surface; a shift member mounted on a support member in a configuration permitting movement along the shift surface of the support member between a first mode position corresponding to a first mode of operation and a second mode position corresponding to a second mode of operation; characterized by: the support member having a lock surface; the shift member having a cooperating lock surface, and the shift member being further mounted on the support member in a configuration permitting movement, when the shift member is in the first position, between a lock position where the lock surface can engage against the cooperating lock surface, and an unlock position where the lock surface cannot engage against the cooperating lock surface; a biasing member configured to exert a locking force on the shift member toward the lock position; an actuation member coupled to the shift member in a configuration that, during shifting between the first mode of operation and the second mode of operation, generates an unlocking force sufficient to overcome the locking force and to move the shift member to the unlock position, and thereafter, the actuation member moving the shift member along the shift surface of the support member from the first mode position to the second mode position. the support member having a lock surface; the shift member having a cooperating lock surface, and the shift member being further mounted on the support member in a configuration permitting movement, when the shift member is in the first position, between a lock position where the lock surface can engage against the cooperating lock surface, and an unlock position where the lock surface cannot engage against the cooperating lock surface; a biasing member configured to exert a locking force on the shift member toward the lock position; an actuation member coupled to the shift member in a configuration that, during shifting between the first mode of operation and the second mode of operation, generates an unlocking force sufficient to overcome the locking force and to move the shift member to the unlock position, and thereafter, the actuation member moving the shift member along the shift surface of the support member from the first mode position to the second mode position.