Vernier Height Guage.docx

Experiment No 3 Objective: To measure the Height of object by using Vernier Height Guage

Apparatus:  Vernier Height Guage  Work piece Theory: Vernier height gauge is similar to vernier caliper but in this instrument the graduated bar is held in a vertical position and it is used in conjunction with a surface plate. A vernier height gauge consists of (i) a finely ground and lapped base. The base is massive and robust in construction to ensure rigidity and stability. (ii) A vertical graduated beam or column supported on a massive base. (iii) attached to the beam is a sliding vernier head carrying the vernier scale and a clamping screw. (iv) an auxiliary head which is also attached to the beam above the sliding vernier head. It has a fine adjusting and clamping screw. (v) a measuring jaw or scriber attached to the front of the sliding vernier. In a vernier height gauge, as illustrated in Fig .3, the graduated scale or bar is held in a vertical position by a finely ground and lapped base. A precision ground surface plate is mandatory while using a height gauge. The feature of the job to be measured is held between the base and the measuring jaw. The measuring jaw is mounted on a slider that moves up and down, but can be held in place by tightening of a nut. A fine adjustment clamp is provided to ensure very fine movement of the slide in order to make a delicate contact with the job.

Fig. Vernier Height Gauge Unlike in depth gauge, the main scale in a height gauge is stationary while the slider moves up and down. The vernier scale mounted on the slider gives readings up to an accuracy of 0.01 mm.

Fig.4 Vernier Height Gauge Vernier height gauges are available in sizes ranging from 150 to 500 mm for precision tool room applications. Some models have quick adjustment screw release on the movable jaw, making it possible to directly move to any point within the approximate range, which can then be properly set using the fine adjustment mechanism.

Fig. Measurement of Height using Vernier height gauge Vernier height gauges find applications in tool rooms and inspection departments. Modern variants of height gauges such as optical and electronic height gauges are also becoming increasingly popular.

Procedure: 

. The base of the height gauge is first wiped clean and placed on a flat surface such as a surface plate and is checked for error, by observing that zero of the vernier coincides with the zero of the main scale when the measuring pointer just touches the reference surface.



. The workpiece is then placed on the surface plate and the slider is moved with the help of slider clamping screw and the measuring jaw is placed on the surface of the specimen, so that it just touches the surface of the workpiece whose height is to be measured.

Employ the same precautions as in vernier caliper experiment to ensure application of correct measuring force. 

Now the measuring jaw is firmly clamped.



Read the measurements as below Main scale reading = A Vernier scale reading ×least count = B Final reading = A+B

Observation and Calculation Sr No

Main scale (A)

CONCLUSION:

Vernier scale

V.s*L.C

Total reading

(B)

A+B