Countersinking is an operation of bevelling the end of a drilled hole. The tool used is called a countersink.
52) The process of beveling the end of existing hole is called
Related Cutting Tools MCQ - Machinist(Set-1) with Answers
The working surface of the job and the bottom surface of cutting edges of chisel
For conduit and other thin tubing, sheet metal work etc. use a 0.8 mm pitch.
For soft materials such as bronze, brass, soft steel, cast iron, heavy angles etc. use a 1.8 mm pitch blade.
The taper shank drill should be removed from the machine spindle by means of tool called drill drift.