[M4 |  Durchgangsloch Fein]

With a flat countersink, also referred to as countersinker, a 180° countersink is created. For this purpose, a hole must already have been drilled so that the spigot of the countersink can centre. The main application is countersinking the screw head of a cylinder head screw. Three variants are offered for this, tolerance medium, fine and core hole of a thread.