Starrett 256RL-1 Disc-Type Micrometer, Ratchet Stop, Lock Nut, 0-1" Range, 0.001" Graduation, +/-0.00015" Accuracy

The Starrett 256RL series Disc-Type micrometer has disc-shaped faces with flanges for measuring the distance between gear teeth, a vernier scale in inch units for taking precise outside diameter (OD) measurements, and a ratchet-stop mechanism for uniform pressure during adjustment. The vernier scale on the thimble and sleeve is graduated to 0.001”. The micrometer has a tapered frame for measuring narrow slots and tight spaces, and is made of high-grade tool steel with a satin chrome finish that helps resist rust and reduce glare. A knurled ring-type lock nut helps provide secure locking of the measurement position.

Micrometers 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. Micrometers are typically used in manufacturing, machining, and mechanical engineering. There are three types of micrometer: outside, inside, and depth. Outside micrometers may also be called micrometer calipers, and are used to measure the length, width, or outside diameter of an object. Inside micrometers are typically used to measure interior diameter, as in a hole. Depth micrometers 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.