Question

The ratio of the number of teeth to the pitch circle diameter in millimeters, is called

(a) circular pitch

(b) diametral pitch

(c) module

(d) none of the mentioned

The question was posed to me at a job interview.

Question is taken from Systems of Gear Teeth in division Toothed Gearing & Gear Trains of Machine Kinematics

Answer 1

Correct option is (b) diametral pitch

To explain I would say: Diametral pitch is the ratio of number of teeth to the pitch circle diameter in millimetres.

Circular pitch is the distance measured on the circumference of the pitch circle from a point of one tooth to the corresponding point on the next tooth.