Measuring Calipers

Measuring Calipers:

First of all, keep in mind that the topic under discussion is “calipers” not the vernier caliper.


The measuring tool with two extended arms or legs which are generally used to measure or transfer reading of internal and external diameters of objects, thicknesses of different parts and point to point distances.

measurement by caliper


Caliper has two legs same like compass and different type is used for each external and internal measurement.

Extreme end of each leg is its measuring point that called Tip.

Different types of tips are fabricated to cope up various measurement requirements and to meet different measuring conditions. The legs are adjustable to open and close position for a certain range in every caliper.


Pivoted Joint/Function joint:

Also called function joint the point where both legs are pivoted to each other. That junction allows caliper legs to move freely to open or close position, when required.


The functioning part of caliper is its leg.As the length of legs increases, measuring range of caliper increases too.


Lower extreme end of a leg called tip or measuring tip. It is the main contact point between the caliper and object to be measured. A different tip design makes different caliper type.

Spring loaded lock screw:

Its main function is to avoid free movement of caliper legs when measuring. It helps to freeze a measured value and eliminates error probability.

Only opening and closing of locking screw allows the legs to move. It helps user to make fine adjustments.

caliper construction and types


There are many shapes and tip designs of caliper for different purposes but mainly four types:

Inside Caliper:

Its measuring tips direction is outward side and opposite to each other so used for internal measurements.

Outside Caliper:

Its measuring tips are facing each other (inward side) so used for external measurements as both tips are in same direction.

Divider Caliper:

It is mostly used to transfer the same dimensions from one object to another object or part. Its other uses are to draw the parallel lines, circles and divide objects into equal parts. Divider makes marking through its scriber type tips.

Odd leg caliper:

It has a bent leg on one side and scriber on the end of other leg, that’s why called odd leg.

This caliper is  normally used to make marking of a line at the desired distance from an object’s edge. It always draws a line parallel to edge of work piece, because the bent leg slides along the edge and other leg engraves line on a certain distance where both legs are adjusted.

 Why it’s called Indirect measuring tool?

Caliper not indicates measured value directly and only can transfer the value to a measuring instrument or tool like measuring tape or steel rule.

At very small level, now days some of calipers are provided own scale to indicate measurement directly.It is mostly used in medical field like body fat tester caliper and dental caliper those have graduated bow (scale) with sliding pointer on it, to show the result locally. So we can say that calipers are not indirect measuring tools any more but still use of indirect form is applicable in heavy industry, mechanical workshops for big parts where tolerances are ±1 mm or greater.

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