 CP = Circular Pitch in inches 

DP = Diametral Pitch 
CP = 3.141 / DP


The composite action test (double flank) is a method of inspection in which the work gear is rolled in tight double flank contact with a master gear or a specified gear, in order to determine (radial) composite variations (deviations).The composite action test must be made on a variable center distance composite action test device.and this is composite action test for double flank
Cone distance in a bevel gear is the general term for the distance along an element of the pitch cone from the apex to any given position in the teeth.