Toothed pully design information needed.

Can anyone on the list give or point to an accurate source of information on
cutting Stepper Pulleys? I have been working with mklotz@...
(Marvin W. Klotz), on writing a utility for all the parameters, he is doing
the work, I don't know enough. We based initial information on an article in
Engineering In Miniature, July 1988. However some of the formulas don't seem
to work correctly, or at least they don't agree with the information that is
in the Stock Drive catalog.
Any and all help would be greatly be appreciated.
bill