Gun drill gun drill machining for mandatory use of chip. High pressure cutting oil from entering the gun drill bit shank bore, reach the cutting area of ??the drill blade cooling lubrication. Iron and cutting oil discharged along the drill "V" groove. Also known as external chip. Gun drill machining a wide range of materials. From fiberglass, Teflon and other plastics to steel, alloy steel, non-ferrous metals and then to high-strength alloy steel (such as high temperature resistant alloys, titanium) are available to its deep hole machining. Excellent performance due to hole machining, gun drill in shipbuilding, automobiles, engines, locomotives, military, chemical machinery, glib pumps, mining machinery and hydraulic parts and other industries are widely used. Gun drill machining precision deep hole machining using appropriate tools and cutting parameters, processing results can be achieved as follows: Aperture size: IT6 ~ IT611 bore roughness: Ra0.2 ~ Ra6.3 skewness: 1/1000 × hole depth fixed workpiece, tool rotation 0.5 / 1000 × hole depth workpiece rotation, reverse rotation tool gun drill gun drill machining efficiency as a special tool structure, in the deep processing, no refund crumbs, once processed into depth. The deeper the hole deeper, more processing efficiency can be reflected. Depending on the material and pore size, processing speed can be achieved 30-100mm / min or more.