Vernier Caliper
Fig. shows the vernier caliper, which is commonly
used to measure accurately(1) outside diameters of shafts,
(2) thicknesses of various parts,
(3) diameters of holes or rings and
(4) internal dimensions of hollow jobs or articles.
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| Vernier Caliper |
It works on the principle of vernier and can measure the dimensions to an accuracy of 0.02 mm. For making a measurement of external dimensions, the job is placed between the fixed and the movable jaws. The movable or the sliding jaw is moved until it almost contacts the job kept against the fixed jaw. The sliding jaw assembly of the vernier caliper that carries the fine adjustment screw should be clamped to the graduated beam with the help of adjustment clamp. The two jaws are then brought into contact with the job by moving the sliding jaw with the help of fine adjustment screw. The jaws should make now definite contact with the job but should not be tight. The main slide assembly is then locked to the beam with help of clamp. The caliper is then carefully removed from the job to prevent springing the jaws and the reading is taken. For making a measurement of internal dimensions, the job is placed outward between the fixed and the movable jaws meant for measuring inner dimension.
Vernier Depth Gauge
Vernier depth gauge is basically employed for checking
depths of blind holes such as grooves, slots, depth of key ways and heights of
shoulders, etc. The principle on which it works is the same as that of a vernier caliper. It is available with similar measuring accuracies as the vernier caliper and readings are taken the
similar manner. It consists of a
movable head with a base, which
moves along the beam. A main scale on the beam and vernier scale on the sliding
head with fine adjustment screw are incorporated in the similar manner as in a
vernier caliper.Vernier Height Gauge
Fig. illustrates the vernier height gauge, which is employed for measuring the
height of parts and in precision marking work. It consists of a heavy base, an
accurately finished bottom, a vertical bar mounted square to the base, carrying
the main scale, a sliding head with vernier, an auxiliary head with fine
adjustment screw and nut and a bracket attached to the sliding head. This
bracket is provided with a clamp by means of which interchangeable jaws can be
fixed over there. The jaws can be fixed for measuring height or replaced by
scribing jaws according to requirement or need. The graduations on the height
gauge are given in Fig. |
| A vernier height gauge |
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| A graduation on the vernier height gauge |
vernier caliper
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