The Precision Twist R15B jobber-length, general-purpose, round-shank drill bit drills holes with best performance in alloyed hardened steel, nodular graphite malleable cast iron, titanium, and alloyed nickel. It can drill to a depth up to four times the diameter of the drill size. The shank diameter is the same as the drill size.
While the R15B series was designed for the aircraft industry, it also works well for drilling into a variety of materials. The jobber length and 135-degree split-point drill geometry provide adequate reach and ensure a more accurate hole by reducing walking when the hole is started. The finish retains lubricant to aid in wear resistance and chip flow.
The Precision Twist R15B series has a type N flute form, with a regular helix (21- to 34-degree) angle. The steam tempering finish gives a strongly adhering blue oxide surface that acts to retain cutting fluid and prevent chip to tool welding, reducing the formation of a built-up edge. Spiral flutes act as a passageway for chip extraction from the hole and for coolant to enter the hole. Right-hand twist brings chips up and away from the cutting edge.
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 sizing) and NAS 907 type B industry standards, which 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.