In drilling, a cylindrical hole is produced in workpiece, removing the material inside the workpiece. The cutting tool
used in drilling operation is called ‘Twist Drill’; it rotates and allows the material to be removed from the workpiece in the form
of chips and thus drill the hole. Cutting fluids or coolants are used to perform this operation smoothly. The coating on the drill
bits helps to reduce friction in the cut and the heat buildup in the drill bit. Coating also helps in protecting against corrosion.