pedal axle : what size is it ? (answer is here)

what size is a bike pedal axle diameter (to fit the crankset) ?
the big question (and answer).
are there lots of different pedal axle sizes ? (no).
what about Thread Per Inch (TPI) ? ... probably always 20 TPI ? (think so).

[@dperreno]

I would say that any bike made in the last 40 years has is 9/16" x 20 tpi. You can find different sizes on older bikes, but the industry standardized on this size quite awhile ago.