Every hole edge needs a chamfering after drilling. A hole may need countersink machining to let a screw sit onto it properly. Every sharp edge on the machined part may need chamfering and get deburred. That’s why countersinking and chamfering is a standard division of machining and professional tooling for it so essential.
Ground surface and relief angles of flutes as well as coating of a countersinking tool play important role in its performance and can improve technical aspects such as chip clearance, chatter-free working, centering and scratch-free surface finishing.
Dimensionally, countersink tools are known by angle and maximum diameter of the cutting edge.
By angles they are categorized in 60, 82, 90, 120 degrees. 60 degree is a good choice in a threaded hole or in tool and jig making industry, 82 degree in machining room for flat head countersink UNC screws and 90 degree category for 45 degrees chamfering.