micromètre

Micrometre, also known as a micrometer screw gauge, is a precision measuring instrument used to determine extremely small distances or thicknesses. It is commonly used for measurements of length, thickness, and external diameter. The device operates on the principle of a calibrated screw mechanism. A precisely machined screw thread is rotated, moving a spindle towards or away from an anvil. The distance moved by the spindle is indicated on a barrel, which is often marked with a scale.

The accuracy of a micrometer depends on the precision of its screw thread and the clarity of its scales. Typical micrometers can measure to within 0.01 millimeters or 0.0001 inches. There are various types of micrometers, including outside micrometers, inside micrometers, and depth micrometers, each designed for specific measurement tasks. Outside micrometers are used to measure the external dimensions of an object, such as the diameter of a wire or the thickness of a plate. Inside micrometers are used to measure internal dimensions, like the diameter of a hole. Depth micrometers are used to measure the depth of a recess or hole.

Calibration is crucial for ensuring the accuracy of a micrometer. Regular calibration against known standards, such as gauge blocks, is necessary to maintain its precision. Micrometers are widely used in manufacturing, engineering, machining, and scientific research where precise dimensional measurements are required. Their ability to measure with high accuracy makes them indispensable tools for quality control and detailed work.