Formula Sheet

m = module 

N = number of teeth

PA = Pressure angle = degrees

a = Addendum = m

b = dedendum = 1.25 * m

dP = pitch diameter = m * N

dbc = base circle diameter = dP *  cos(PA)

D = diametral pitch = 25.4 / m

P = circular pitch = Pi / D

ht = whole depth = 2.157 / D

c = clearance

hk = working depth = 2 / D

b = face width
n = speed (rpm)
w = transmitted power (hp)
V = velocity of pitch diameter = Pi * dP *n / 60000
Ft = tangential force = (w*745.69987) / V
LS = Lewis tooth stress = Ft / (m * b * Y)