The Cleveland 2133 screw machine length, high-speed steel (HSS) containing cobalt drill bit has a 30-degree helix angle, with a 135-degree split-point drill point and straw oxide surface treatment, which is designed for heavy-duty drilling applications. The shank diameter is the same as the drill size. This drill has high red hardness for extended wear life in high heat conditions. The 2133 series performs best when drilling into stainless steel, tool steel, carbon steel, and cast iron. Straw oxide is a low-temperature heat treatment that reduces grinding stress within the tool. Spiral flutes act as a passageway for chip extraction from the hole and for coolant to enter the hole. The twist of the flutes brings chips up and away from the cutting edge. 135-degree split-point reduces walking when starting a hole and penetrates more easily than a convention point. Round shanks allow use with a wide variety of tool holding systems. The screw machine length, also called short or stub length has shorter flute and overall length for more rigidity and accuracy. Designed to reduce deflection and breakage than longer length drill bits. Made of cobalt-powder-metal substrate which is many times harder and 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 ANSI and DIN 1897 industry standards, which help ensure that drill bits around the world, conform to the same specifications. The tolerances for various aspects of the Cleveland drill bits are: drill diameter range (inches) through 1/8 +0.0000/-0.0005, over 1/8 through 1/4 +0.0000/-0.0007, over 1/4 through 1/2 +0.0000/-0.0010, over 1/2 through 1 +0.0000/-0.0012, over 1 through 2 +0.0000/-0.0015, over 2 through 3 1/2 +0.0000/-0.0020; drill overall length and flute length #80 through 1/8 +0.1250/-0.0626, over 1/8 through 1/2 +0.1250/-0.1250, over 1/2 through 1 +0.2500/-0.1250, over 1 through 2 +0.2500/-0.2500, over 2 through 3 1/2 +0.3750/-0.3750; drill point angle diameter range (inches) 1/16 through 1/2 included angle (degrees) 118 or 135 +/-5 degrees, over 1/2 through 1 1/2 included angle (degrees) 118 +/-3 degrees, over 1 1/2 through 3 1/2 includes angle (degrees) 118 +/- 2 degrees; drill lip height diameter range (inches) 1/16 through 1/8 total indicator variation (inches) 0.0020, over 1/8 through 1/4 total indicator variation (inches) 0.0030, over 1/4 through 1/2 total indicator variation (inches) 0.0040, over 1/2 through 1 total indicator variation (inches) 0.0050, over 1 through 3 1/2 total indicator variation (inches) 0.0060. 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. Greenfield Industries, which are a part of Top-Eastern Group, is one of the largest manufacturers of twist drills. They also manufacture cutting tools and related products under the following brands: Cleveland, Chicago-Latrobe, Cle-Line, Vermont Tap & Die, Bassett, Putnam Tools, Geo Met RJC, H & G, Vers-O-Tool, and Acme-Fette. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.