The Precision Twist R18 jobber drill bit is a conventional point, general-purpose, round shank drill 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. Good for portable or machine drilling. The shank diameter is the same as the drill size. It was designed for drilling holes into a wide variety of metals and synthetic materials.
The R18 series has a type N flute form, with a regular helix (21- to 34-degree) angle have best performance drilling into steel or cast iron. The finish retains lubricants to aid in wear resistance and chip flow. 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 ANSI (fractional sizing) industry standards, which ensure that drill bits around the world conform to the same specifications.
Precision manufactures machine tools under the following brands: Precision Twist, Precision Dormer, and Union Butterfield. They have locations around the world, and provide tools adhering to ANSI, NAS, and DIN standards.