countersink from M3 to M12

Metal cassette with 7 HSS countersinks. The 4-edged flat cores have a fixed guide pin that guides the counterbore in the bore. The 180 ° countersinks are suitable for the production of countersinks in through holes for cylinder screws DIN912 from M3 to M12. The flat shields are delivered in a metal cassette. In order to produce a cylindrical depression, one proceeds as follows. First of all, a drill is produced with a spiral drill, which is 0.1 mm larger than the diameter of the spindle core. Subsequently, the cylindrical countersink is produced with the appropriate countersink while being guided through the bore.