Starrett 486MP-50 Blade-Type Micrometre, Non-Rotating Spindle, Plain Thimble, 25-50mm Range, 0.01mm Graduation

The Starrett 486 series blade-type outside micrometre has a Vernier scale in metric units for taking precise outside diameter (OD) measurements, and a blade anvil and spindle for measurement of groove diameter of shafts and keyways. The spindle does not rotate during adjustment, to help provide steady positioning for measurement. A speeder helps provide quick adjustment capability. The frame is made of high-grade tool steel and has a black enamel finish for protection and durability. The Vernier scale on the thimble and sleeve is graduated to 0.01mm, and has a satin chrome rust- and glare-resistant finish. The spindle and anvils are made of hardened steel for durability. Micrometres are precision measuring instruments that use a calibrated screw to measure small distances. These measurements are translated into large rotations of the screw that are then able to be read from a scale or a dial. Micrometres are typically used in manufacturing, machining, and mechanical engineering. There are three types of micrometre: outside, inside, and depth. Outside micrometres may also be called micrometre callipers, and are used to measure the length, width, or outside diameter of an object. Inside micrometres are typically used to measure interior diameter, as in a hole. Depth micrometres measure the height, or depth, of any shape that has a step, groove, or slot. The L.S. Starrett Company manufactures precision measuring tools, metrology and testing equipment, and saw blade products. The company was founded in 1880 and is headquartered in Athol, MA.