Precision Twist 4ASMCO Cobalt Steel Short Length Drill Bit, Bronze Oxide Finish, Round Shank, Spiral Flute, 135 Degree Split Point, 8.00mm (Pack of 6)

The Precision Twist 4ASMCO stub-length drill bit is a heavy duty, 135-degree, spilt-point, round shank drill bit made of high-speed steel and cobalt with a bronze oxide finish. They meet NAS 907 aircraft industry specifications for heat resistance and use for drilling hard, tough materials. This is best used drilling into hardened, tempered alloy steel, nodular graphite, malleable cast iron, titanium, nickel, and other hard materials such as cemets (metals-ceramics). It is suitable for drilling to a depth up to two-and-one-half times the diameter of the drill. The shank diameter is the same as the drill size.Made with cobalt which is many times harder/stiffer than HSS, will hold an edge longer, and will 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 DIN 1897 (metric sizing) industry standards, which ensure that drill bits around the world, confirm to the same specifications. The 4ASMO series has a type N flute form, with a regular helix angle (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. 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 DIN 1897 industry standards (metric sizing), which helps 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.

• Adheres to NAS 907 standards, used in the aerospace industry
• Short-length drill bits, for better rigidity and increased strength
• High-speed steel (HSS) containing cobalt is a good combination of toughness and hardness, for use on drilling through hard substances
• Gold oxide, retains cutting fluid and prevent chip to tool welding
• 135-degree split point angles, good for hard, tough materials