Abstract: The plunger of a baler for making parallelepiped bales is driven by an extensible and retractable hydraulic actuator that is connected for oscillating a link forming a crank coupled to the plunger by a connecting link. The dimensions and locations of the crank and connecting link relative to the hydraulic actuator results in the plunger being moved in the baling chamber through a distance which is about twice the stroke of the actuator when the plunger is moved from a fully retracted position, at one side of an inlet used for introducing crop into the chamber, to a fully extended position at an opposite side of the inlet from the fully retracted position.