Question

Which of the following is generally used to check the hardness of the gauging surface of screw ring gauges?

(a) Rockwell hardness testing machine

(b) Charpy hardness testing machine

(c) Diamond pyramid machine

(d) Scratch test

I had been asked this question by my school teacher while I was bunking the class.

Question is from Measurements of Limit Gauges topic in division Testing and Calibration of Gauges and Dynamic Measurement of Engineering Metrology

Answer 1

Right choice is (d) Scratch test

The explanation is: The hardness of the gauging surface of limit gauges may be generally measured on a hardness testing machine, preferably on the diamond pyramid machine. In certain types of gauges like screw and plane ring gauges, hardness is checked by means of a scratch test.