Question

Which of the following is not correct when minor and major diameter have errors?

(a) Will cause interference between mating parts

(b) Flank contact increases

(c) Less root section

(d) Less wall thickness

I got this question during an interview.

Question is from Effect of Pitch Errors topic in section Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Correct option is (b) Flank contact increases

The explanation: Errors on the minor and major diameters will cause interference in the mating thread. Due to errors in minor and major diameter, the wall thickness and root section will be less, also the flank contact will be decreases and the component will be weak in strength.