Abstract: The ram of the reciprocating saw is driven by a scotch yoke mechanism. A planetary gear system consisting of a ring gear and an idler gear imparts an elliptical or linear path of movement to the pin forming part of the scotch yoke mechanism. The ring gear may be adjustably positioned for changing its relationship relative to the idler gear thereby varying the orientation of the elliptical or linear path of movement of the drive pin for varying the stroke of reciprocation of the ram which is connected to the saw blade holder. Actuation of the ring gear to its desired position automatically causes the foot plate of the saw to be located in its desired position for the selected stroke of movement.