DIN 6540-2
DIN 6540-2 Technical delivery conditions for solid hardmetal twist drills according to DIN 6537 and DIN 6539; inspection
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 04/01/1993
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 04/01/1993