The Precision Twist R41 short-length drill bit, is a round shank bit made of HSS with a steam tempering (black oxide) finish. It is suitable for drilling to a depth up to four times the diameter of the drill. The shank diameter is the same as the drill size. For best performance, use for drilling into steel, stainless steel, cast iron, and titanium.
The R41C series was designed for the aircraft industry, but also works well for drilling into a variety of materials. The short length and 135-degree split-point drill geometry provide a stable and rigid platform and ensure a more accurate hole by reducing walking when the hole is started. 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. The finish retains lubricant to aid in wear resistance and chip flow.
The R41C series has a type N flute form, with a regular helix angle of 21 to 34 degrees. Uncoated tools have no finish or coating. They are a common choice for general use applications. The short-stub length has more rigidity for drilling straighter, shallower holes than Jobber-length bits. 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.
and away from the cutting edge. They are made to ANSI (fractional sizing) and NAS 907 type C industry standards, which help ensure that drill bits around the world conform to the same specifications.