For general purpose use point angle of twist drill is 118 Degree.
For general purpose use point angle of twist drill is 118 Degree.
The relief angle given behind the cutting lips is called Lip Clearance angle
Counter-boring is the process of enlarging the end of an existing hole to accommodate the head of socket screw.
Countersinking is an operation of bevelling the end of a drilled hole. The tool used is called a countersink.