Top-10 Mechanical Measuring Instruments

Here is some most commonly used mechanical instruments for measurement in industries. Without this instruments I don’t think any quality process possible.

Highlights of this blog in this Video

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01. Vernier Caliper

Vernier Caliper is a widely used linear measurement instrument with a least count of 0.02 mm. It is used to measure linear dimensions like length, diameter, depth.

It is Basic Instrument of measurement, consist of two types of scale

vernier  caliper mitutoyo

The main scale and the Vernier scale that can slide along the main scale. Two types of measurement we can do, the first one is through external jaw (measure external dimensions) and another one is internal jaw (measure internal dimensions).

How to use vernier caliper?

02. Micrometer

External Micrometer is also known as Outside Micrometer or External Micrometer.

It is used to check outside diameter of circle by the means of accuracy of 0.01 mm or up to 0.001 mm.

baker micrometer specification

Vernier type Micrometer gives highest acceptable accuracy of 1 micron such gauge is vernier type micrometer.

How to use micrometer

Difference between Micrometer and Vernier caliper

1. Usually Micrometer is more accurate and precise than Vernier caliper

2. Measurement range of micrometer is 25 mm while vernier caliper has wide range.

3. You can check depth by vernier caliper but in case of micrometer you have to use Depth Micrometer

4. Inside Micrometer is used for measurement of inner diameter but in case of vernier caliper it is checked by internal jaw.

Basics and difference vernier caliper and micrometer

03. Steel Scale

Steel scale is single piece linear measuring instrument. Steel scale indicates two units that are cm and inches, cm division on one side and inches, on another side.

Watch full video to understand engineering scale

04. Vernier Height Gauge

Vernier height gauge used to measure vertical dimension from reference ground. Vernier Height Gauge consist of a graduated scale or bar is held in a vertical position by a finely ground fixed base.

The graduated scale has least count of 0.02 mm like Vernier Caliper has. And the way of taking a reading of measurement in Vernier Height Gauge is same as in Vernier gauge.

Vernier Height Gauge
How to use vernier height gauge?

05. Vernier Depth Gauge

Vernier Depth Gauge as the name suggests is used to measure the depth from the surface of reference of an object. Vernier caliper also has depth bar but this can not be used as the standard measurement.

See the least count and how to use depth vernier?

06. Bevel Protractor

A simple protractor is a basic device used for measuring angles with a least count of 1° or ½°. Bevel Protractor is an angular measuring instrument capable of measuring angles with a least count of  5’.

bevel scale

The protractor dial is graduated in degrees with every tenth degree numbered. The sliding blade is fitted into this dial I.e. it may be extended to either direction and set at an angle to the base.

07. Dial Gauge (Plunger, Level)

The dial indicator or the Plunger dial gauge is one of the simplest and the most widely used mechanical comparator.

First of all the use of plunger dial gauge used to compare work-pieces against a master

See video for more

Lever Dial Gauge also knew as Test Indicator. It used to measure sensitive contact.

Lever Dial gauge usually measure up to 0.80 mm. But some special type lever dial design for measurement up to 2 mm. 

lever dial gauge
Lever type dial gauge

08. Engineering Square

A ruler can be used to draw straight lines but there is no quarranty that the line drawn is accurate and exactly straight,this is where the engineering square is brought into use.

engineering square

An engineering square also known as machinist square is similar in size and construction to a try square.

It is a tool used for making straight lines and are used to measure angles.

09. V Block

In Industries where precise marking and firm holding of objects is required, V-Blocks play a major role and are extremely important metalworking jigs.

The construction had two clamps:screw clamp and a U shaped handle like clamp and a V-block .


The materials used are hardened tool steel and cast iron. The V-block is used as a locator and a centralizer.

It is mostly used to fit round or cylindrical objects tight and rigid for easy marking or cutting.

10. Radius Gauge

Gauges are derived from the French word”jauge” which means the result of the measurement. We are all aware that gauges are used to measure the thickness, size or capacity of something.

concave and convex shape

Likewise, radius gauges are instruments that are used to measure the radius of the object.

blades of radius gauge

The radius gauge is combined with another gauge known as fillet gauge which in mechanics means a rounding of the part design

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