Precision Twist 501 12 High Speed Steel Extra-Long Drill Bit, Black Oxide Finish, Round Shank, Spiral Flute, 135 Degree Point Angle, #46 (Pack of 12)

The Precision Twist 501-12 extra length, aircraft extension drill bit, is a round shank bit made of HSS with a steam tempering (also called 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. Best performance with drilling into hardened, tempered alloy steel, stainless steel, and titanium; these should be less than 30 on the Rockwell C hardness scale. While the 501-12 series was designed for aircraft industry, they also work well for drilling into a variety of materials. The extra length and 135-degree split point drill geometry provide extra reach and ensure an accurate hole by reducing walking when the hole is started. The finish retains lubricants to aid in wear resistance and chip flow. 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, 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.

• NAS 907 type B standards, used in the aerospace industry
• Extra-length drill bits, provide long reach
• 135-degree split point angles are self-centering, reduces walking, good for hard material, and reduces pressure on cutting edges
• Steam tempering (back oxide) finish, retains cutting fluid and prevents chip to tool welding
• High-speed steel (HSS), for use on a wide variety of materials