Question

The normal lead, in a worm having multiple start threads, is given by

(a) lN = l / cos λ

(b) lN = l . cos λ

(c) lN = l

(d) lN = l tan

I have been asked this question by my college professor while I was bunking the class.

I need to ask this question from Worm Gears topic in division Toothed Gearing & Gear Trains of Machine Kinematics

Answer 1

The correct option is (b) lN = l . cos λ

To elaborate: The term normal pitch is used for a worm having single start threads. In case of a worm having multiple start threads, the term normal lead (lN) is used, such that

            lN = l . cos λ

where lN = Normal lead,

l = Lead, and

λ = Lead angle.