Use and Reading of Micrometer in Thousandth Inch

Micrômetro polegada - Micrometer inch - Micrómetro pulgadas
Reading and interpretation of micrometer in thousandth of inch

Use of the instrument of measurement ‘micrometer’ in the english system and thousandth resolution: reading and interpretation

This page assumes that you have already interacted with the page: micrometer in millimeter hundredth resolution – use, reading and interpretation and with the page: reading of ruler or line gauge, in tenth inch.

The operation of the micrometer in thousandth inch

figure 1 – thimble in partial view to reveal the shealth marks

A complete turn in the thimble (and of the fuse) produces the advance equal to the thread pitch. The screw of this fuse, usually, has the lenght of the one inch and the pass of 25 thousandths of inch.

In the sleeve there is a graduation that controls the advance of the thimble/fuse – figure 1. The inch (10 tenths) is divided by nine main marks, the distance between them is the tenth of inch, these marks have numbers to help the reading. The tenths of inch are divided by three marks that control the advance of twenty and five thousandth of inch (0.1/4 in = 0.025 in). This means that each time that a new mark is revealed by the thimble, the fuse moved close to twenty and five thousandth of inch(0.025in).

The resolution of the thousandth inch micrometer

The configuration most commonly found in the metal / mechanical workshops is the micrometer spindle having a pitch of 0.025 in and the barrel 25 divisions-Figure 2. Thus, by turning the micrometer spindle each marking of the barrel passing through the ‘Reference line’ will indicate that The movable stopper moved away (or approached) 0.001 in (one thousandth of an inch).

figure 2 – image of the graduation of the thimble corrected to reveal the 25 marks/divisions

Reading of the micrometer in thousandth inch by the measurement formation


  • to determine the value of the measure, it is necessary to add:
  • the value obtained in the graved scale in the sleeve, in tenths of inch (0.1in)
  • represented by the ( o ) ‘in green color’ in the animation below
  • with 0.025in x number of counters of 0.025in exposed (0.1in /4 in)
  • represented by ( o ) ‘in blue color’
  • with the value of the thimble aligned with the ‘reference line’, in thousandths of inch
  • represented by ( o ) ‘in the orange color’
  • click in the icon in the inferior corner of the interactive screen animation to alternate the value of the measure
  • use the icon ‘eye’ to hide the values total and partial
  • with the ‘eye closed’, click in the colored circles to show the value related to them

Commented examples of reading and interpretation of micrometer in thousandth inch

The comprehension of the reading of this instrument is very intuitive for those who know the vernier scale: simulator of reading and interpretation in thousandth inch resolution 0.001″ . Evidently, it is necessary to transfer the manipulated data given by the vernier to the one given by the thimble. See also the figure 2 of the page: Micrometer in inch with resolution tenth of thousandth – use, reading and interpretation

Eduardo Stefanelli

Engenheiro por profissão, professor por vocação

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