Question

Which of the following is not true for contact points used in dial indicators?

(a) These are generally blackened

(b) Made of hardened steel

(c) General purpose contact point is of square form

(d) Contact end is polished

This question was addressed to me during an interview for a job.

My query is from General Care of Dial Gauges topic in division Dial Indicators and Indicating Gauges of Engineering Metrology

Answer 1

The correct option is (c) General purpose contact point is of square form

Explanation: The contact points are made of hardened steel and blackened to avoid rusting. To prevent scratching of workpiece, the contact end is polished. The general purpose contact point is of spherical shape.