Centre Drill Type-A
The centre drill type-A is used for drilling a hole on the axis of a shaft to hold it between centers. It was also used to drill center holes on machining centers, but has been replaced by the spot drill (which has a simpler geometry) for this purpose. The Type A forms a centre hole with a single 60 degree chamfer. The Drills for centers can be constructed in high speed steel but also in carbide. The centre drill type-A is very efficient.