- The thimble rotates around a cylinder which is marked in millimeters
- The left-hand side of the thimble has markings all around it
- The line labeled 0 is the primary pointer.
Close the jaws
Calculate the least count
Place the object between the two jaws (Anvil andspindle), Spin ratchet until you hear 3 clicks.
Record the position of main scale where the twomeasuring rods met
Note the position of the circular scale whichcoincides with main scale.