afce3e68_Worm_Gears__Having
[S. no.] 16 [To Obtain] Lead Angle of Worm [Rule] Multiply the Pitch Diameter of the Worm by 3.1416 and divide the product by the Lead, the Quotient is the cotangent of the Lead Angle of the Worm. [Having] 
Pitch Diameter of the Worm and the Lead
Worm Gears
Having