Micrometer in Thousandth of Millimeter – Reading and Interpretation

Micrômetro - Micrometer - Micrómetro
Use and reading of micrometer in milesimal millimeter

Use of the instrument of measurement ‘micrometer’ in the metric system and milesimal resolution: reading and interpretation

This text will exclusively address the interpretation of the milesimal part of the micrometer. If you are not yet versed in the use, reading, and interpretation of the centesimal part of the micrometer, interact with this page before proceeding.

This text assumes that you are familiar with the nomenclature of the components of the Micrometer <- if necessary, remember by clicking here and with the reading of ruler or line gauge, in millimeter <- remember by clicking here.

Operation of the milesimal millimeter micrometer

figure 1 – Drum in partial cut to reveal the nickel dividing the hundredth of an inch by ten

The main difference of this configuration is that it has ten lines parallel to the ‘baseline’ engraved in the sheath. Another difference is in the position of the middle marks – Figure 1

The resolution of the thousandth micrometer, the reading of the vernier.

In the centesimal micrometer, the resolution was obtained by dividing the thread pitch of the micrometreic fuse by the number of divisions of the thimble (Resolution = thread pitch of the micrometric fuse / number of the thimble divisions) or Tesolution = 0.5mm / 50 = 0.01mm.

On this thousandth micrometer, the smallest difference between indications is divided by ten by a vernier engraved in the shealth. This way, the resolution will be: Resolution = 0.01mm / 10 = 0.001mm.

Reading of micrometer in thousandth millimeter

Commented examples of micrometer reading in thousandths millimeter

Animation 1 – reading of the measure by the sum of the parcels
  • To determine the value of the measure, it is necessary to sum:
    • the value read in the scale engraved in the shealth, in millimeter
      • represented by ( o ) ‘in green color’ in the animation below
    • with 0.500mm in case the counter of half millimeter it is exposed
      • represented by ( o ) ‘in blue color’
    • with the value of the thimble aligned with the ‘refference line’, in centesimal millimeter
      • represented by ( o ) ‘in orange color’
    • with the value read in the vernier, aligned in the thimble, in thousandth millimeter
      • represented by ( o ) ‘in red color’
Eduardo Stefanelli

Engenheiro por profissão, professor por vocação

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