Question

Which of the following is not true about effective diameter?

(a) Also known as pitch diameter

(b) It decides quality of fit between nut and screw

(c) This is the diameter of minor cylinder

(d) It is a very important dimension for screw threads

The question was asked in exam.

My enquiry is from Screw Threads Terminology topic in division Metrology of Screw Thread, Gauges for ISO Metric Screw Threads of Engineering Metrology

Answer 1

Correct option is (c) This is the diameter of minor cylinder

The explanation is: In case of straight thread, effective diameter is the diameter of the pitch cylinder and is also called as pitch diameter. Effective diameter is the most important dimension at it decides the quality of the fit between the nut and the screw.