Question

Why are shallow grooves provided in larger flats?

(a) To minimize the possibilities of uneven hardening

(b) For design purpose

(c) To maintain high accuracy for a longer period

(d) To make them lighter

This question was addressed to me in an online interview.

My question is from Tool Maker’s Flats and High Precision Surface Plates topic in division Linear Measurements of Engineering Metrology

Answer 1

Correct choice is (a) To minimize the possibilities of uneven hardening

To explain I would say: A shallow groove is provided around the periphery of larger flats to avoid uneven hardening and for easy handling.