Monday, March 30, 2020

Vernier caliper | Find out its least count?



Vernier caliper is a measuring device which is used for measurement of length, width, outer/inner diameter of hole.
It is based on the principle of "Difference between two scales".

Vernier caliper
Application of Vernier Caliper
Vernier Caliper is made by carbon steel and also solid and durable in nature. It is easy and convenient to use due to its high accuracy. The measuring range is 150mm, measuring accuracy is up to 0.02mm, that is its least count. 


389 years ago, when there was no vernier caliper, it was impossible to measure the dimensions of any object less than 0.1 mm. 
Due to which, the industry's workers had to face a lot of difficulties related to measurement in making child parts & sub-child parts.
But in 1631, a French mathematician named  Pierre Vernier considered this topic and solved this problem. He invented a vernier scale that can measure less that 0.1 mm. 

Pierre Vernier

The device is named on his name, which we known as Vernier caliper. At that time, in the industrial sector, this device gives an accuracy in measurement that was a big change. With this help, we can easily measure Minimum at least 0.02 mm dimension. It provides an accuracy to measurement system.
Vernier caliper


  • Main scale & Data scale 
  • Vernier scale & Indicating scale 
  • Locking screw 
  • Metallic strip/tail 
  • Upper & lower jaws 

Main scale: 

Main scale is calibrated in inches at top side of scale. It is calibrated in mm at bottom side of scale.
Vernier scale

Vernier scale

Vernier scale has readings at also both side (Top side & Bottom side).
Vernier scale

Locking screw: 

We used locking screw to lock the movement between main scale and vernier scale so that we can easily measure the dimensions of any object. 
Locking screw

Fine adjustable screw: 

This screw is used for adjustment of vernier scale during measurement.
Adjustable screw

Metallic strip: 

It is used for measurement of depth in hole of any object.
Metallic strip/tail

Upper & lower jaws: 

Upper jaws is used for internal measurements and lower jaws is used for outer measurements. In this, one is fixed jaw and second is movable jaw.
Fixed jaw is located with main scale and movable jaw is located with vernier scale. 
Upper & lower jaws

Find out the least count of vernier caliper:

50 vernier scale readings is equal to 49 main scale reading.

Least count = 1 Main scale division - 1 Vernier scale division

1 Main scale division = 1 mm

1 Vernier scale division = 49/50 mm
= 0.98 mm

Least count = 1 mm - 0.98 mm = 0.02 mm

We hope you will understand this topic.

Thank you.

Some of related question that help to improve your basic knowledge.

Clamping force | How to calculate the clamping force in injection molding machine |

 CLAMPING FORCE:  Clamping force is an engineering term used in mechanical and manufacturing processes. The meaning of clamping force is to ...