Abstract: An automatic tapping device for use on a mechanical press including a screw member fixed rigidly to and extending from the upper surface of a lower block and a reversible actuating nut engaged on the screw and a rotary tapping-bit holder spindle rotatably mounted in an upper block. The actuating nut and the rotary tapping-bit holder are interconnected by a chain transmission, including gear wheels borne by an intermediate shaft. The invention is applicable to the tapping of parts on mechanical presses, such as eccentric stamping presses or deep-drawing presses.