Vernier Calipers

How to Measure using vernier calipers:

- Make sure the jaws are adjusted to touch the opposite sides whose distance is to be
measured.
- Place the calipers on a ruler to measure the distance between the jaws.
 

As the metre rule or measuring tape are only accurate to 0.1 cm. For greater precision, we
need special instruments: vernier calipers and micrometer screw gauge.

Introduction

The vernier calipers is used to measure lengths accurately to 0.01 cm or 0.1 mm. Readings can be read off using the instrument itself without using a ruler. This instrument comprises of 1 external calipers, 1 internal calipers and a tail for measuring depths.

Method of reading

1. Close the jaws and ensure that the zeros present on both the vernier and main scale 

form a straight line. 

2. Jaws are then adjusted and clamped onto the object to be measured. 

3. Note the reading on the main scale. 

Note the reading on the vernier scale. 

4. Final reading = main scale reading + vernier scale reading. 

 

Zero error: 

Occurs when the zero marks on vernier scale and main scale failed to align when the jaws are completely closed completely. 

Positive zero error: 

Initial Reading (without taking account of zero error) is overestimated as the zero mark of the vernier scale lies on the right of the main scale.  

Hence Actual reading = Initial reading - Zero error

 

 

Negative zero error:

 Initial Reading (without taking account of zero error) is 

underestimated as the zero mark of vernier scale lies on the left 

of the main scale.  

Hence actual reading = Initial reading + zero error

 

  

As a precaution, always REMEMBER TO CHECK FOR ZERO ERROR 

BEFORE USE OF VERNIER CALLIPERS

.