It is the precision instrument and with its help outer, inner and depth of any job can be measured in metric system of 0.02mm to and 0.001 inch in British system because it has both the scale metric and British.

It is normally made of chromium steel.


  1. Fix jaw
  2. Main scale
  3. Vernier head
  4. Moveable jaw
  5. Fine adjusting screw and nut
  6. Depth beam
  7. Inside measuring jaws
  8. Locking screw
Parts of vernier caliper

  • Fix jaw : it is a part of beam and fitted at right angle and faces for outer and inner measurement.
  • Bin or main scale : it is a wide mild flat having main scale marked in mm and inch. Movable jaw side on has head and fine adjusting head which can be adjusted on beam as per requirement.
  • Vernier head : it is a main part of caliper having vernier scale on it. An aur like fixture is fixed. To make the head stationery a locking screw with this is fitted.
  • Movable jaw : the measurement with the help for movable job and fixed jaw for outer, inner and height of the job is measured with this.
  • Fine adjusting head : it is attached with the journey ahead with the help of screw and nut. It is used to measure precision measurement. Before to take accurate reading app.set the one year ahead then for fine adjusting lock it with its main scale with locking screw now with the help of fine adjusting not sift the hernia head slightly forward or backward to get accurate measurement.
  • Depth beam: to take the modern Vernier caliper more useful, a very thin piece is attached at the back side of hernia head which slide between grove in main scale.another stopper piece with screw is fixed at last end of main scale which keeps the depth beam in proper position.
When zero lines of main scale and vernier scale meet each other then dipped beam tip is equal to main scale surface end.p it is used to measure group or hool deapth. It is also called depth gauge or depth bar.
  • Inside measuring jaw : some vernier caliper has Jaw opposite to out jaw . To reduce the torch surface its age is made like nife sharp. This jaws are used to measure with of groove for inner diameter.
  • Locking screw : it is used to lock the adjusting head with main scale. 
Some Kali parts do not have separate jaw for measuring inner measurement after leaving some point person of outer jaw it's below part is designed smaller inside known as nib .this small portion is made around for limited thickness so while taking the inner reading by such calibre the thickness of an nib is added in caliper reading.

3 . List count of vernier caliper

The minimum reading by Vernier calliper is known as Vernier caliper list count. It is 0.02 mm in metric system and 0.001 inch in British system.

Method of find out one year caliper least count in metric system. Scale is graduated in two ways in metric system.
  1. Main scale is graduated to 1 mm mark.
  2. Main scale is graduated to 2 mm and 1/2 (0.5) mm.
Least count: those calipers having only mm graduation mark their main scale 49 mm distance is equally divided into 50 division.

Main scale 1 division = 1 mm
Main scale 49 division=49 mm
Vernier scale 50 division= main scale 49 division.

4. Method of metric vernier reading

Before taking the reading see the position of zero line in main scale of vernier scale and note the division it is crossed.

Now at 0.5 mm division reading in it.then multiply by 0.022 graduated Mark matched with main division of vernier scale and add this to first reading.
During reading of vernier caliper the following value should be known
  1. Main scale 1 man division value=1 mm=1 mm
  2. Main scale 1 subdivision value=0.5mm=0.5 mm
  3. 1 vernier division value=0.02 mm=0.02 mm

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