Question

A conical spring is to be designed with base diameter 100 mm and another end diameter 50 mm and pitch of spring is 5 mm to a height of 80 mm. How many revolutions are there in spring?

(a) 15

(b) 16

(c) 17

(d) 18

This question was posed to me during a job interview.

The doubt is from Helix upon a Cone topic in section Curves used in Engineering Practice of Engineering Drawing

Answer 1

The correct choice is (b) 16

The explanation is: Whatever the end diameters of a conical spring the number of revolutions depends on the pitch and height of the spring. Number of revolutions = length of spring/pitch of helix = 80 mm/5 mm = 16.