A punch press uses a punch tool assembly which contains at least two punch pins of different diameters or cross-sections which are readily interchangeable in the working position by a control element which is slidable about the pin support member, and actuating means. When the punch tool assembly is rotatable about the ram to effect the movement of the punch pins from operative to inoperative positions, then a cooperating movable die is provided in order to ensure that the aligned die bores are cooperatively dimensioned and configured with respect to the punch pins.