The Precision Twist R56 Jobber-length, uncoated, general-purpose, round shank drill bit drills holes into a wide variety of metals and synthetic materials with best performance with steel, stainless steel, cast iron, titanium, and nickel. It can drill to a depth up to four times the diameter of the drill size. Flute length is three inches, overall length is six inches, with a half inch, reduced shank.
Combination black oxide and bright finish improves lubricity, resists corrosion, and will not chip or flake off. Black oxide also helps to prevent buildup and welding of material on the cutting edge when working with iron and steel.
Reduced shanks are smaller than the drill diameter, so they can drill holes larger than the typical chuck capacity. These are sometimes called Silver & Deming drills; they used to be made by Silver & Deming in the late 1800's, but nowadays, it's come to mean any reduced shank twist drill bit.
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 can be used in hand operated drills, standalone drill presses or a machine tool called a lathe, to drill a hole. 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 the chips up and away from the cutting edge. They are made to ANSI standards, which ensure that drill bits around the world, confirm 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.