Precision Twist R18CO Cobalt Steel Jobber Drill Bit, Bronze Oxide Finish, Round Shank, Spiral Flute, 135 Degree Point Angle, 56 (Pack of 12)

The Precision Twist R18CO jobber-length drill bit is a 135-degree spilt-point, heavy duty, round shank drill bit made of high speed steel (HSS) and cobalt with a bronze oxide finish. They meet NAS 907 Type J, aircraft industry specifications for heat resistance and use for drilling hard, tough materials. Best performance with drilling into hardened, tempered alloy steel, nodular graphite malleable cast iron, titanium, and alloyed nickel. 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. While the R18CO series was designed for aircraft industry, they also work well for drilling into a variety of materials. The 135-degree split point drill geometry help ensure an accurate hole by reducing walking when the hole is started. The finish retains lubricants to aid in wear resistance and chip flow. The R18CO series has a type N flute form (a regular helix of 21 to 34 degrees). The bronze oxide is a low temperature heat treatment which reduces grinding stress within the tool, and has an appealing, easy-to-identify bronze color. Bronze oxide is commonly used to identify cobalt steel tools. Made of HSS with cobalt which is many times harder/stiffer than HSS, it will hold an edge longer, and deflect less than HSS. These are also more resistant to heat than HSS. These qualities allow it to run at higher speeds and feeds. They are made to ANSI (fractional sizing) industry standards, which ensure that drill bits around the world conform to the same specifications. 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.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
• Gold oxide, retains cutting fluid and prevent chip to tool welding
• 135-degree split-point angles are self-centering, reduce walking, good for hard material, and reduce pressure on cutting edges
• High-speed steel (HSS) containing cobalt, for use on abrasive materials and high cutting temperatures
• Jobber-length drill bits and the most common length drill bit, suitable for a wide range of applications