Question

Which of the following is not used to measure the plain plug gauges if the tolerance less than 0.025 mm?

(a) Bench micrometer

(b) Diameter measuring machine

(c) Hand micrometer

(d) High magnification dial comparator

The question was posed to me in an interview.

The origin of the question is Measurements of Limit Gauges in section Testing and Calibration of Gauges and Dynamic Measurement of Engineering Metrology

Answer 1

The correct option is (c) Hand micrometer

The best I can explain: If the tolerance on the plug gauge is less than 0.025 mm then, it is important to use more accurate measurement method. In such cases, bench micrometer or high magnification dial comparator or diameter measuring machine should be employed. In this case, hand micrometer can only measure over a limited range of size.