A hydraulic system in a bow saw machine, operating in conjunction with a carriage carrying the bow for the saw blade, and providing for the application of the saw blade to a workpiece in the machine, the application of sawing pressure during a cutting stroke, and the retraction of the blade from the workpiece during a return stroke. A crank drive and guide structure disposed between the carriage and the bow provide for reciprocal, rectilinear guided movement of the blade with respect to the workpiece clamped on a pedestal of the machine. The hydraulic system has a cylinder-piston assembly wite the cylinder connected to the carriage and with the piston connected, through a piston rod, to the pedestal. A pump and a charging piston in the system are in hydraulic communication with a first chamber in the cylinder of one side of the piston and are operated by actuating elements associated with the crank drive. Hydraulic fluid under pressure, as supplied by the charging piston and pump, acts to apply and retract the saw blade with respect to the workpiece. In addition, a fluid under pressure, supplied from a reservoir, constantly acting within a second chamber on the other side of the piston provides an arrangement to compensate for the weight of the carriage and the components carried on it.