This experimental presentation explains about the usage of the vernier caliper. It starts with a definition of the vernier caliper, then goes on introducing the parts, errors, special definitions and as to how a measurement could be taken.

1. VERNIER CALIPER
By Aditya Abeysinghe
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3. Like the micrometer screw gauge, the vernier caliper is
used to take measurements that are accurate to within
.001 of an inch or .02 of a millimeter or in other words it’s
used to make very precise measurements which cannot be
accurately measured from a meter scale
INTRODUCTION

4. PARTS OF A VERNIER CALIPER
Fixed jaw Movable jaw
Outer jaws
Fixed jaw Movable jaw
Inner jaws
For internal
measurements
For external
measurements
Vernier scale
Main or meter
scale
Fine adjustment
screw
Lock
Depth rod
(to
measure
depth)

5. Least count- Least Count refers to the smallest distance that can be measured using
an instrument. Most of the vernier Calipers have a least count of 0.1mm.
Least Count = Length of 1 MSD – Length of 1 VSD
Where MSD and VSD refer to Main Scale Division and Vernier Scale Division
respectively
Generally N divisions on main scale coincide with N-1 divisions on vernier scale
1 VSD is equivalent to (N-1)/N main scale divisions
Using the formula for Least Count, we get
LC = 1 MSD – 1VSD
= 1 MSD – (N-1)/N MSD
= 1/N MSD
SPECIAL DEFINITIONS ON CALIPER
MEASUREMENTS

6. E.g.:
A vernier scale has the length of 9 main scale divisions
and is divided into 10 divisions.
Since 9 divisions of the vernier scale coincide with 10
divisions of the main scale
VSD = 9 / 10 mm = 0.9 mm
MSD= 1 mm (the least length that can be measured from
the main scale – 1/10 cm)
Least Count= 1 MSD- 1VSD = 1mm - 0.9mm = 0.1mm
*The least count may vary between different vernier
calipers.

7. Although the least count may vary between different
calipers, the length formula for any caliper is as follows:
Length = MSR + (VSR * LC)
Where MSR, VSR and LC refer to Main Scale Reading,
Vernier Scale Reading and Least Count respectively.
LENGTH FORMULA FOR A
VERNIER CALIPER
0
0

8. Any vertical caliper may have two types of errors:
1.Positive zero error
2. Negative zero error
Positive zero error –
Occurs when the zero of the vernier scale is to the right of the
vernier scale when the two jaws are in contact.
To take the precise value for the measurement we are taking,
we have to substract the value of the positive zero error from
the obtained measurement.
ERROR IN A VERNIER CALIPER

9. Negative zero error –
Occurs when the zero of the vernier scale is to the left of the vernier
scale when the two jaws are in contact.
To take the precise value for the measurement we are taking, we have to
add the value of the negative zero error to the obtained measurement.
0
0
0
0
Positive Zero Error
Negative Zero Error

10. No zero error is the precise arrangement of the meter
scale and the vernier scale so that the zeros of both
scales fit each other as follows:
To take precise measurements, we have to ensure that
the caliper we are using is of no zero error.
NO ZERO ERROR
0
0

11. 1. First find whether there’s an error on the caliper.
2. Second find its least count(LC)
3. Place the object between the appropriate jaws (outer/inner) or on the
depth rod according to the measurement.
4. The reading of the main scale (MSR) which is to the left of the zero
of the vernier scale is the Main Scale Reading
5. Now look up for the no. of divisions on the vernier scale which
exactly coincides with any of the main scale reading. This is the
Vernier Scale Reading(VSR)
6. The length of the object is calculated using the formula: Length =
MSR + (VSR * LC)
7. If there’s an error in the caliper add or substract depending on the
type (positive error/negative error)
TAKING A MEASUREMENT

12. There are three types of measurements that can be
measured with a vernier caliper.
They are:
1. Measuring the external width/external diameter of an
object with outer jaws
2. Measuring the internal width/internal diameter of an
object with inner jaws
3. Measuring the depth of an object with the depth rod
E.g.: Measuring the length of a test tube.
TYPES OF MEASUREMENTS

13. 1. First find whether there’s an error on the
caliper.
2. Second find its least count(LC)
3. Place the object between the outer jaws
4. The reading of the main scale (MSR) which is to the left of the zero of the
vernier scale is the Main Scale Reading
5. Now look up for the no. of divisions on the vernier scale which exactly coincides
with any of the main scale reading. This is the Vernier Scale Reading(VSR)
6. The length of the object is calculated using the formula: Length = MSR + (VSR *
LC)
7. If there’s an error in the caliper add or substract depending on the type (positive
error/negative error)
MEASURING WITH OUTER JAWS

14. 1. First find whether there’s an error on the
caliper.
2. Second find its least count(LC)
3. Place the object betweenthe inner jaws
4. The reading of the main scale (MSR) which is to the left of the zero of the
vernier scale is the Main Scale Reading
5. Now look up for the no. of divisions on the vernier scale which exactly coincides
with any of the main scale reading. This is the Vernier Scale Reading(VSR)
6. The length of the object is calculated using the formula: Length = MSR + (VSR *
LC)
7. If there’s an error in the caliper add or substract depending on the type (positive
error/negative error)
MEASURING WITH INNER JAWS

15. 1. First find whether there’s an error on the
caliper.
2. Second find its least count(LC).
3. Keep the object in contact with the brim
of the vernier caliper. Extend the depth rod
until it meets the depth to be measured.
4. The reading of the main scale (MSR) which is to the left of the zero of the vernier
scale is the Main Scale Reading.
5. Now look up for the no. of divisions on the vernier scale which exactly coincides
with any of the main scale reading. This is the Vernier Scale Reading(VSR).
6. The length of the object is calculated using the formula: Length = MSR + (VSR *
LC).
7. If there’s an error in the caliper add or substract depending on the type (positive
error/negative error).
MEASURING WITH DEPTH ROD
Vernier caliper
Object whose
depth is to be
measured
Depth rod