Gun drill

Other uses include moldmaking, diemaking, and the manufacture of combustion engine parts such as crankcase, cylinder head, and woodwind musical instruments, such as uilleann pipes, as gun drills can drill long straight holes in metal, wood, and some plastics.

The coolant provides lubrication and cooling to the cutting edges and removes the swarf or chips from the hole.

This is a problem in many manufacturing processes, especially the firearms industry: the barrel of a gun must be very straight and accurately sized.

Gun barrels are far longer than their inside diameter; as an example, the .223 inches (5.7 mm) caliber barrel of the M16 rifle is 20 inches (510 mm) long, nearly 90 times the diameter of the bore.

For diameters between 1–3 mm, gun drilling can be performed successfully with special equipment.