Calipers are indirect measuring instruments used for transferring measurements from a steel rule to a job, and vice versa.
Calipers are classified according to their joints and their legs.
Classification of calipers based on joints
- Firm Joint Calipers
- Spring Joint Calipers
Classification of calipers based on legs
- Inside caliper for internal measurement
- Outside caliper for external measurement
Calipers are used along with steel rules, and the accuracy is limited to 0.5 mm; parallelism of jobs etc. can be checked with higher accuracy by using calipers with sensitive feel.
Spring joint calipers have the advantage of quick setting with the help of an adjusting nut. For setting a firm joint caliper, tap the leg lightly on a wooden surface.
Jenny calipers have one leg with an adjustable divider point, while the other is a bent leg. These are available in sizes of 150 mm, 200 mm, 250 mm and 300 mm.
Jenny Calipers are used for
for marking lines parallel to the inside and outside edges
for finding the centre of round bars.
These calipers are available with the usual bent leg or with heel.
Calipers with bent leg are used for drawing lines parallel along an inside edge, and the heel type is used for drawing parallel lines along the outer edges.
This calipers also called as hermaphrodite calipers, leg and point calipers and odd leg caliper.