Question

The base diameter of a conical helix is 100 mm. The angle between the base and slanting side is 45 degrees. Pitch of helix is 5 mm. What is the height of helix and number of revolutions?

(a) 50 mm, 10

(b) 25 mm, 5

(c) 30 mm, 7

(d) 100 mm, 15

I got this question in examination.

My question is from Helix upon a Cone in division Curves used in Engineering Practice of Engineering Drawing

Answer 1

Correct answer is (a) 50 mm, 10

Easiest explanation: Base radius = 50 mm.  Angle given is 45 degrees. Tan (angle) = height/ base, tan (45) = height/ 50, height = 50 x tan (45) = 50 mm, so at height of 50 mm the helix end. Number of revolutions = height/ pitch = 50 mm/ 5 mm = 10.