The diametral pitch of an ANSI B92.1 involute spline as the standard writes it: the pitch over
the stub pitch that sets the teeth's depth, such as 16/32. These are the pitches the standard
gives its 30 degree flat root side fit, 2.5/5 to 32/64; the finer ones it makes only with a
fillet root or at 45 degrees.
The diametral pitch of an ANSI B92.1 involute spline as the standard writes it: the pitch over the stub pitch that sets the teeth's depth, such as 16/32. These are the pitches the standard gives its 30 degree flat root side fit, 2.5/5 to 32/64; the finer ones it makes only with a fillet root or at 45 degrees.