DIN 6351-1
DIN 6351-1 Lathe chucks, hand-operated - Jaws with centrical clamping individually adjustable - Part 1: Cylindrical mounting recess
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 05/01/2010
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 05/01/2010