The Dormer A900 Spectrum jobber-length drill bit is a 130-degree, PFX point, round shank drill bit made of high-speed steel (HSS) and cobalt. It can drill holes up to six times the diameter of the drill. The shank diameter is the same as the drill size. It is recommended that ER collets be used in the following size ranges: 3/64” – 25/32”, A – Z, 60 – 1, 1.0 – 20.0mm.
The A900 series has a type W flute form, with a fast helix angle of 35 to 45 degrees, and are most suitable for drilling into steel, stainless steel, titanium, nickel, and alloyed aluminum. This design allows for single-pass drilling, which helps eliminate the need for pecking in up to six times the drill diameter deep holes, thus offering improved efficiency and increased productivity. The composition of HSS and cobalt offers a combination of toughness and hardness needed for deep hole drilling. The parabolic design, combined with a parallel thinned web, allows for smooth and efficient chip removal. With proper cutting conditions and a rigid machine setup, holes to H10 tolerance can consistently be achieved.
The uncoated finish helps increase chip flow. Spiral flutes act as a passageway for chip extraction from the hole and for coolant to enter the hole. The right-hand twist brings chips up and away from the cutting edge.
Made of HSS with cobalt which is many times harder and stiffer than HSS, will hold an edge longer, and will deflect less and are more resistant to heat than HSS. These qualities allow it to run at higher speeds and feeds. They are made to ANSI and DIN industry standards, which help 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.
Precision manufactures machine tools under the following brands: Precision Twist, Precision Dormer, and Union Butterfield. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.