A machine-tool comprises a column (1, 2, 3) with two fastening elements (22 and 39) for a coping saw blade (31). The element (22) is driven in a vertical to-and-fro movement by an electric motor (5). The elements (39 and 22) are mutually connected by a metallic band (45) passing over pullies (46 to 50). The position of the pulley (47) can be varied by a cam (53) acting on an arm (52) to tighten the band (45) to the desired value.