This International Standard specifies the basic dimensions and tolerances, in millimetres, of punches with cylindrical head and straight or reduced shank. Cylindrical head punches with reduced shank are standardized in round, oblong, square and rectangular shapes. This International Standard gives examples of materials and their hardness, and specifies the designation of punches. These punches are available with shank diameters, D1, from 3 mm to 32 mm. The main use of the punches specified in this International Standard is for punching holes in steel sheet. They may also be used for punching in other materials.