Diametral Pitch

Diametral pitch, abbreviated as DP, is the ratio of the number of teeth to the pitch circle diameter.

 

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

 

Diametral Pitch formula
\(\large{ DP = \frac{\pi}{CP} }\)
Symbol	English	Metric
\(\large{ DP }\) = dimetrical pitch	\(\large{dimensionless}\)
\(\large{ CP }\) = circular pitch	\(\large{in}\)	\(\large{mm}\)
\(\large{ \pi }\) = Pi	\(\large{3.141 592 653 ...}\)

 

Diametral Pitch formula
\(\large{ DP = \frac{n_p \; \left( GR \;+\;1 \right)  }{2 \; CD} }\)
Symbol	English	Metric
\(\large{ DP }\) = dimetrical pitch	\(\large{dimensionless}\)
\(\large{ CD }\) = center distance	\(\large{in}\)	\(\large{mm}\)
\(\large{ GR }\) = gear ratio	\(\large{dimensionless}\)
\(\large{ n_p }\) = number of teeth on the pinion	\(\large{dimensionless}\)