Gundrilling is a deep hole drilling process that uses a long, thin cutting tool to produce holes in metal at high depth-to-diameter ratios. Gun drilling is effective in diameters from 1 – 50 mm. A gundrill tool differs from a conventional twist drill by its unique head geometry; a standard gundrill has a single effective cutting edge that removes chips as it advances into a metal workpiece.
The gundrilling process is able to drill deep holes beyond what is possible with conventional machinery and tooling such as twist drills, by using high pressure coolant for clean chip exhaust, even at extreme depths.
Gun drilling was initially developed for the manufacture of gun barrels, where both straightness and barrel durability were essential to properly functioning barrels. The gundrilling process and tooling have been refined for maximum performance and use on modern, dedicated machinery. Firearms continue to be a common application for gundrilling. Other industries include diesel fuel components, medical tooling, plastic injection molds, and more.
Gun drilling can be done, with limited performance, on common CNC machines. Holes with a depth-to-diameter ratio of 20:1 or greater generally require dedicated equipment to achieve the highest productivity and process reliability, and can reach extreme ratios of 400:1 or greater.
Gun drilling process is used to produce deep and straight holes. This process is very specialised as compared to the conventional twist drilling process. The standard gun drill tool geometry has a single effective cutting edge. Unlike the twist drill the gun drill cuts through the metal eccentrically and once inside the component the tool self-pilots itself. The hole is further burnished due to the guide pads which finally results in a precise round hole with maintained straightness.
The Coolant enters the tool through the coolant through hole and the chips are gushed out through the V shaped profile on the gun drill. Gun Drilling is effective from ф1 to ф30mm, but if you wish to go bigger in diameter, BTA drilling becomes more effective than gun drilling.