The Precision Twist QC91G taper-length drill bit is a parabolic flute design, 135-degree radius, split-point, round shank drill bit made of HSS with a TiN finish, which is a hard, gold-colored ceramic coating that has low friction, permitting faster cutting speeds than uncoated materials. It is suitable for drilling to a depth up to six times the diameter of the drill. Good for portable or machine drilling. The shank diameter is the same as the drill size. It was designed for drilling holes into a wide variety of metals and synthetic materials with best performance in steel, cast iron, copper, and aluminum magnesium. The QC91G series has a wide land parabolic flute design that enhances chip (also called swarf) formation and evacuation. Coolant has a better flow to the drill point for heat dissipation, and can operate at higher speeds and feeds for increased productivity. It is recommended to use a constant heavy feed rate while drilling. This design has a reinforced web which provides increased drill strength and rigidity, and straighter, closer tolerance holes. Drilling, or hole making, is the most common metalworking operation in the world. Twist drill bits are the most common type of drill bit used. Twist drill bits are commonly used to drill holes with hand-operated drills, standalone drill presses, or lathes. The flutes of the drill bit act a passageway for chip extraction from the hole and for coolant to enter the hole. These drill bits have a right-hand twist that brings chips up and away from the cutting edge. They are made to ANSI (fractional) industry standards, which helps ensure that drill bits around the world conform to the same specifications. Dormer Pramet manufactures cutting tools under the following brands: Precision Twist Drill, Dormer, Union Butterfield and Pramet. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.
