Pitch Diameter

Pitch diameter, abbreviated as PD, is the diameter of a gear pitch circle.  The pitch diameter is used to generate the pitch circle.

 

Pitch Diameter formula
\(\large{ PD = \frac{n}{DP} }\)
Symbol	English	Metric
\(\large{ PD }\) = pitch diameter (diameter of pitch circle)	\(\large{in}\)	\(\large{mm}\)
\(\large{ DP }\) = dimetrical pitch	\(\large{in}\)	\(\large{mm}\)
\(\large{ n }\) = number of teeth on the diameter	\(\large{dimensionless}\)

 

Pitch Diameter formula
\(\large{ PD = \frac{n \; CP }{\pi} }\)
Symbol	English	Metric
\(\large{ PD }\) = pitch diameter (diameter of pitch circle)	\(\large{in}\)	\(\large{mm}\)
\(\large{ CP }\) = circular pitch	\(\large{in}\)	\(\large{mm}\)
\(\large{ n }\) = number of teeth on the diameter	\(\large{dimensionless}\)
\(\large{ \pi }\) = Pi	\(\large{3.141 592 653 ...}\)