Precision Twist R10CO Cobalt Steel Jobber Drill Bit, Bronze Oxide Finish, Round Shank, Spiral Flute, 135 Degree Point Angle, 5/16" (Pack of 6)

The Precision Twist R10CO jobber-length drill bit is a 135-degree, spilt-point, heavy-duty, round shank drill bit made of HSS and cobalt with a bronze oxide finish. For best performance, use for 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 R10CO 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 good 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 R10CO series has a type N flute form (a regular helix angle 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, will hold an edge longer, and will deflect less than HSS. They are also more resistant to heat than HSS. These qualities allow it to run at higher speeds and feeds. 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 type J 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.

• NAS 907 type J standards, used in the aerospace industry
• Gold oxide, retains cutting fluid and prevent chip to tool welding
• 135-degree split-point angle is self-centering, reduces walking, good for hard material, and reduces pressure on cutting edges
• High speed steel (HSS) containing cobalt is a good combination of toughness and hardness, for use on drilling through hard substances
• Jobber-length drill bits is the most common length drill bit, suitable for a wide range of applications