Requirement
With a standard twist drill, it is difficult to drill a straight and accurately sized hole of a depth more than about 5 times the diameter. 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 inch (5.56 mm) caliber barrel of the M-16 rifle is 20 inches (508 mm) long, nearly 90 times the diameter of the bore. The gun drill was developed to drill such long, straight holes.
Gun drilling is possible over a range of depths and diameters. For diameters between 1-3mm, gun drilling can be performed successfully with special equipment. It is a common process between 3-50mm in diameter. It is also possible for the 50-75mm range, however less efficient than BTA deep hole drilling.
Read more about this topic: Gun Drill
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