Precision Twist R41 High Speed Steel Short Length Drill Bit, Uncoated (Bright) Finish, Round Shank, Spiral Flute, 118 Degree Point Angle, 40 (Pack of 12): Home Improvement. Short-length (also called stub), for better rigidity and increased strength 。 118-degree conventional point angles, for general drilling applications 。 Round shanks, for use on a variety of tool-holding systems 。 Uncoated (bright), for use with a wide range of drilling materials 。 High-speed steel (HSS), for use on a wide variety of materials 。 The Precision Twist R41 stub-length, uncoated, general-purpose, round-shank drill bit drills holes into a wide variety of metals and synthetic materials. It can drill to a depth up to two-and-a-half times the diameter of the drill size. The shank diameter is the same as the drill size. 。 The R41 series has a type N flute form, with a regular helix angle of 1 to 34 degrees, with best performance drilling into steel, stainless steel, cast iron, and titanium. 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. 。 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) standards, which helps ensure that drill bits around the world conform to the same specifications. 。 Dormer Pramet manufactures cutting tools under the following brands: , Dormer, Union Butterfield and Pramet. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.。 。 。 。