What is a Vernier Calliper?
The vernier caliper is a measuring instrument that incorporates a main scale, a vernier scale, and a fixed and sliding jaw. Other types of calliper may employ other types of readout such as a dial for least count readout or an electronic digital readout. Three types of measurement can be made with a typical calliper, that is to say, outside, inside, and depth.
Callipers are available in various sizes, with measuring ranges from 100 mm to 3000 mm (4 in. to 120 in. for inch callipers). Generally, callipers that have a measuring range of 300 mm (12 in.) or less are classified as small callipers and ones with larger ranges are classified as large callipers.
Typical measurement resolutions are 0.05 mm for a vernier calliper, 0.02 mm for dial callipers and 0.01 mm for digital callipers.
Types of Callipers:
1) Vernier Callipers: In this Making a measurement with a vernier calliper involves the use of two scales, one being the main scale on the beam and the other the vernier scale:
2) Dial Calliper: Extensive use is made of dial callipers (figure 7) because they provide an easier method of reading when compared with vernier callipers thus allowing quicker measurement. The dial calliper uses the amplification mechanism of a dial gauge. To take a measurement, simply add the position of the pointer on the dial to the reading on the main scale. Before using dial callipers, clean the jaws. The jaws should then be closed and the zero adjusted by rotating the scale bezel. With dial callipers, it is essential to keep the toothed rack clean. Contamination can cause the pinion gear to jump and lead to the pointer not returning to zero.
3) Digital Calliper: The digital caliper has a digital display and generally uses a linear encoder as its displacement detection system. This linear encoder may be capacitive, inductive, or magnetic. The advantages of this type of instrument are ease of reading and operation and enhanced functionality. Before electronic callipers are used, clean the jaws. After cleaning, close the jaws and set the zero.
Uses of Callipers:
