Precision Twist R57 13/16 Black & Bright High Speed Steel Reduced Shank Drill Bits 118 Degree – 1/2 Shank with 3-Flats 091552

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