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External/Outside Micrometer

It is used to check the outside diameter of the circle by the means of the accuracy of 0.01 mm or up to 0.001 mm. Vernier type Micrometer gives the highest acceptable accuracy of 1 micron such gauge is vernier type micrometer.

external micrometer mitutoyo

How to Measure with Micrometer?

micrometer scale

According to the above figure, the last unit of the main scale is 8 mm. The bottom scale has a span of 0.50 mm, if we see this graduation we have to be added 0.50mm to actual reading.

The second scale is the rotational scale with a number of 0 to 50. Each number shows digit after dot point. For instance 0.46 mm appear at the matching line.

The accuracy of External Micrometer 0.01 mm which is very acceptable,  accurate and precise .

There is another kind of micrometer available called vernier micrometer, which also gives an accuracy of 0.001 mm. Digital and External(Analog)  both Micrometer follow national or international measurement standards by the mean of its unit is mm or inches.

The cost of a Digital Micrometer is a little bit higher than the External type. If we think cost related to the accuracy, that is fair enough. Cost may vary brands to brands, usually depend upon the quality of material and technology used.

You can choose Digital Micrometer with an accuracy up to 0.001 mm, if cost does not matter.

Some most famous Brands which are known for their quality promise available in a market like Mitutoyo, Baker etc.

Digital Micrometer

Digital Micrometer is a very popular instrument these days because of its easy of compactness of taking an observation. Digital Micrometer can observe measurement in mm or inch depend upon our need basis.

The accuracy of Digital Micrometer 0.001 mm which is highly accurate and precise than External Micrometer. You can choose Digital Micrometer with an accuracy of up to 0.001 mm if the cost does not matter.

Digital Micrometer follows national or international measurement standard by the mean of its unit is mm or inches.

Depth Micrometer

We also measure depth through Vernier caliper, but Vernier caliper does not deliver as much accuracy and precision, because the extension rod of Vernier caliper has no standard, it used only for comparison purposes.

Depth micrometer used to measure the depth of an object with precision and accuracy with least count of 0.01 mm. The measuring span is 25 mm just like in micrometer, that can change by changing upsetting rod.

Depth Micrometer by mitutoyo

How to Measure with Micrometer?

Measuring Concept of Depth Micrometer is the same as External Micrometer. The main differences are direction and position. The reading scale is Vertical in-depth micrometer and the Direction of reading is opposite (starting from the end scale).


Some normal characteristics of Depth Micrometer describe follows


The accuracy of Depth Gauge is 0.01 mm which is fair enough for linear measurement and also accurate than vernier caliper. You can choose Digital Depth Micrometer, in order to simplify observation only. Both types of Depth Micrometer delivers the same accuracy.


Depth Micrometer follows national or international measurement standard, while vernier caliper is not(in order to check depth through extension rod only).

The main use of depth micrometer is to check the depth of any objects. Basically used in industrial areas of manufacturing plants.

External source Video for better understanding

Source: YouTube Channel “Weldnotes .com” How to Read a Metric Micrometer

Back to: Introduction to Dimension Measurement

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