Question

Which of the following option is true for truncation?

(a) Thread can be tranculated at crest only

(b) Thread can be tranculatd at root only

(c) Thread can be tranculated at crest and root both

(d) Thread can’t be tranculated at crest and root both

This question was addressed to me during an interview.

My question comes from Screw Threads Terminology topic in chapter Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

The correct option is (c) Thread can be tranculated at crest and root both

The explanation: A thread is truncated sometimes at the crest or at the root or at both root and crest and root. The radial distance from the crest to the nearest apex of the fundamental triangle is truncation at the crest is and at the root it is the radial distance from the root to the nearest apex.