Its is taken standard as 2*pitch circle diameter - 3**pitch circle diameter for cast teeth.

3 *pitch circle diameter - 4 *pitch circle diameter for cut teeth.

Pitch circle diameter = PI*module

regards,

Pranav

circle diameter minus center of pitch cirlce raius

Depends on the pitch:

Fine pitch:

m10 * 0.75 pitch , drill diameter = 9.25 mm

m10 * 1.0 pitch , drill diameter = 9.00 mm

m10 * 1.25pitch , drill diameter = 8.8 mm

Coarse pitch (most common use):

m10 * 1.5 pitch , drill diameter = 8.5 mm

12 is the diameter 14 is the pitch

External diameter / number of gear = pitch