The Chicago-Latrobe 120DHT series parabolic, long length drill bit is made from high-speed steel with a TiN coating and has a 135-degree notched point for use in deep drilling applications on ferrous and nonmetallic materials. High-speed steel (HSS) provides hardness for wear resistance, and the titanium nitride (TiN) coating offers increased wear resistance, extended tool life, and higher hardness than an uncoated drill bit. A self-centering 135-degree notched point penetrates material without a pilot hole more easily than a conventional point, and maintains a sharp cutting edge longer than a split point. The parabolic flutes are wider than standard flutes for improved rigidity in deep drilling applications, as well as increased coolant flow and chip evacuation to reduce clogging. A long length drill bit reaches farther and drills deeper than a jobber length drill bit because it has longer flutes and overall length. The parabolic flutes enable this bit to drill to a depth of 8 to 12 times its diameter. The round shank with tang has a flat shank end for use with positive split sleeve drivers and other drills that accept tanged shanks.
Drill bits are cutting tools used to make holes in a range of materials using machines such as handheld portable drills, machining centers, and lathes. Drill bits come in a variety of lengths and types, the most common of which is the twist drill bit. The round, twisted shaft of the twist drill bit typically has two cutting edges and flutes. The helical twist of the flutes brings chips up and away from the cutting edges and allows for coolant to reach the cutting edges. Jobber length twist drill bits, the most common length of twist drill bit, offer a good compromise of length and reach for the widest range of materials and applications. Mechanic's length twist drill bits (also called maintenance length) are a little shorter than jobber length and less prone to deflection when drilling. Short length twist drill bits (also called stub or screw-machine length) are the shortest and stiffest twist drill bits, helping to reduce the chance of deflection or breakage when drilling. Reduced shank twist drill bits (also called Silver and Deming drill bits) have a shank that is smaller in diameter than its shaft, permitting drilling machines with a 1/4", 1/2", or 3/4" drill chuck to create large holes. Long length twist drill bits (also called taper length) are a little longer than jobber length, allowing for deeper holes and longer reach. Extra-long length twist drill bits (also called extension) are longer than long length twist drill bits for greater reach or for drilling deeper holes.
Chicago-Latrobe manufactures drill bits and accessories, reamers, countersinks, and blanks. The company, founded in 1890 and headquartered in Clemson, SC, meets International Organization for Standardization (ISO) standard 9001.