The Precision Twist R57 Jobber-length, uncoated, general-purpose, 3-flat round-shank drill bit drills holes into a wide variety of metals and synthetic materials with the best performance with steel, stainless steel, cast iron, titanium, and nickel. It can drill to a depth up to four times the diameter of the drill size. The flute length is three inches, overall length is six inches, with a half-inch, reduced shank.
The three flats on the shank are a modification of a straight shank. This allows it to be held in a 3-jaw drill chuck, but not in a collet. This system provides higher torque transmission with limited slipping than a standard straight shank drill bit.
Combination black oxide and uncoated finish improves lubricity, resists corrosion, and will not chip or flake off. Black oxide also helps to prevent buildup and welding of material on the cutting edge when working with iron and steel.
Reduced shanks are smaller than the drill diameter, so they can drill holes larger than the typical chuck capacity. These are sometimes called Silver & Deming drills, which were made by Silver & Deming in the late 1800s. Today, this means any reduced shank twist drill bit.
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 can be used in hand-operated drills, standalone drill presses, or a lathe. 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 the chips up and away from the cutting edge. They are made to ANSI standards, which helps ensure that drill bits around the world, conform to the same specifications.