Question

A screw is said to be over hauling screw, if its efficiency is

(a) less than 50%

(b) more than 50%

(c) equal to 50%

(d) none of the mentioned

The question was asked at a job interview.

Enquiry is from Efficiency of Self Locking Screws in portion Friction of Machine Kinematics

Answer 1

Correct answer is (b) more than 50%

The best I can explain: Efficiency of self locking screws is less than 1/2 or 50%. If the efficiency is more than 50%, then the screw is said to be overhauling.