Micrometer

A micrometer (often micrometer or simply called microns) is a linear encoder.

It consists of a fixed and a variable with a fine thread measuring surface, usually by a bracket ( micrometer ) are interconnected. The part to be measured is placed between the two contact surfaces and the thread (usually knurled ) by an adjusting screw so far turned down until the two contact surfaces contact the part. The Abbe comparator principle is respected.

On a scale parallel to the direction, the size of the part in all pitches of the screw, usually whole or half a millimeter can be read; a second scale around the periphery is used for reading that portion, which accounts for only a fraction of the pitch ( pitch ). Often you can read at this fine scale, the hundredths or thousandths of a millimeter. In order to avoid distortions of the measured value due to different measuring force (deformation of the specimen and the measuring screw ), the thread via a slip clutch, colloquially referred to as a ratchet or feeling screw rotated.

Micrometers also be integrated into other instruments, such as theodolites, leveling instruments and Universal. They are also used to define the glass plates in a variety of optical devices, and to tilt so as to achieve a parallel displacement of the beam path.

For the measurement of interior and exterior dimensions, different measurement screws are required.

Henry Maudslay developed the instrument in 1829, as the measurement results of the devices used hitherto very depended on their handling. This current a vise -like device consisted of the base made ​​of brass and had two jaws made ​​of hardened steel, one of which could be moved by means of a fine screw. Along the guide surface of the jaws there was a split in the tenth of an inch scale, while the crank hundredths and thousandths of inches indicated.