Micrometer screw
Micrometer Mi*crom"e*ter, n. [Micro- + -meter: cf. F. microm[`e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that of the image of the object formed at the focus of the object glass. [1913 Webster]

{Circular micrometer}, or {Ring micrometer}, a metallic ring fixed in the focus of the object glass of a telescope, and used to determine differences of right ascension and declination between stars by observations of the times at which the stars cross the inner or outer periphery of the ring.

{Double image micrometer}, a micrometer in which two images of an object are formed in the field, usually by the two halves of a bisected lens which are movable along their line of section by a screw, and distances are determined by the number of screw revolutions necessary to bring the points to be measured into optical coincidence. When the two images are formed by a bisected object glass, it is called a divided-object-glass micrometer, and when the instrument is large and equatorially mounted, it is known as a heliometer.

{Double refraction micrometer}, a species of double image micrometer, in which the two images are formed by the double refraction of rock crystal.

{Filar micrometer}, or {Bifilar micrometer}. See under {Bifilar}.

{Micrometer caliper} or {Micrometer gauge} (Mech.), a caliper or gauge with a micrometer screw, for measuring dimensions with great accuracy.

{Micrometer head}, the head of a micrometer screw.

{Micrometer microscope}, a compound microscope combined with a filar micrometer, used chiefly for reading and subdividing the divisions of large astronomical and geodetical instruments.

{Micrometer screw}, a screw with a graduated head used in some forms of micrometers; turning the head one full revolution advances the position of the tip of the screw only by a little.

{Position micrometer}. See under {Position}.

{Scale micrometer}, or {Linear micrometer}, a minute and very delicately graduated scale of equal parts used in the field of a telescope or microscope, for measuring distances by direct comparison. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Micrometer screw — Screw Screw (skr[udd]), n. [OE. scrue, OF. escroue, escroe, female screw, F. [ e]crou, L. scrobis a ditch, trench, in LL., the hole made by swine in rooting; cf. D. schroef a screw, G. schraube, Icel. skr[=u]fa.] 1. A cylinder, or a cylindrical… …   The Collaborative International Dictionary of English

  • micrometer screw — micrometer screw, a screw with very fine, precisely cut threads ana head graduated so that the distance traveled by the screw from its base setting may be exactly ascertained. Measurements in units as small as 1/10000 of an inch can be made with… …   Useful english dictionary

  • micrometer screw — [mī kräm′ət ər] n. a finely threaded screw of definite pitch, with a head graduated to show how much the screw has been moved in or out: used in micrometers, etc. to give fine measurements, as of thickness, sometimes to .0001 of an inch * * * …   Universalium

  • micrometer screw — [mī kräm′ət ər] n. a finely threaded screw of definite pitch, with a head graduated to show how much the screw has been moved in or out: used in micrometers, etc. to give fine measurements, as of thickness, sometimes to .0001 of an inch …   English World dictionary

  • micrometer screw — mikrometrinis sraigtas statusas T sritis fizika atitikmenys: angl. micrometer screw; micrometric screw vok. Mikrometerschraube, f; mikrometrische Schraube, f rus. микрометрический винт, m pranc. vis micrométrique, f …   Fizikos terminų žodynas

  • micrometer screw — screw that has a thin thread and is used to tune precision devices …   English contemporary dictionary

  • micrometer screw — /maɪˈkrɒmətə skru/ (say muy kromuhtuh skrooh) noun a screw with a very fine thread and a graduated head, used in micrometers, etc …   Australian English dictionary

  • Micrometer — Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that… …   The Collaborative International Dictionary of English

  • Micrometer caliper — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …   The Collaborative International Dictionary of English

  • Micrometer gauge — Micrometer Mi*crom e*ter, n. [Micro + meter: cf. F. microm[ e]tre.] An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given… …   The Collaborative International Dictionary of English

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