A novel die set and a power pack that is adapted to be mounted thereon define, in part, the improved punch press comprising the present invention. Hollow, magnetizable leader pins having spring actuated stripper buttons therein are used as the armature for the power pack which also includes coil means positioned concentrically about at least one end of the leader pins. The coil means may be made in several discrete sections which are electrically connected parallel to each other and where more than one coil means is utilized, the plurality of coil means are also connected in parallel to each other. The power pack comprising the present invention is readily attachable to the movable portions of the die set.