Patent ID: 7487703

Claim:
A tool for use with a punching press for punching holes in metal workpieces comprising: a punch body, elongated in an axial direction; a first punch head having a first radial diameter, perpendicular to the axial direction, wherein the first punch head is formed on an operative end of the punch body, said first punch head including a leading edge and a following edge each extending perpendicular to the axial direction of the punch body; a conical pointed tip for contacting the workpiece, said tip located at the end of said first punch head, said tip having sidewalls that extend at an angle of between 25 ° and 45°; a second punch head having a second radial diameter, perpendicular to the axial direction, wherein the second punch head is spaced from the first punch head and wherein the first radial diameter is greater than the second radial diameter, said second punch head including a leading edge and a following edge, each extending perpendicular to the axial direction of the punch body; and a neck formed between the first and second punch heads, such that said following edge of said first punch head and said lead edge of said second punch head form surfaces extending perpendicular to the axial direction of the punch body, said neck having a leading edge and a following edge and a uniformly linearly tapered diameter which is less than the first and second radial diameters of said first and said second punch heads, said neck comprising a frusto-conical section with a pitch inclination of between 10° and 50°, the following edge of the neck having a diameter between 50 and 95 percent of the second radial diameter of said second punch head; wherein the tip, the first punch head, the neck and the second punch head are integral parts of a single whole.