FP Gearbox question
 

What is the pressure angle on the final gear of the Fisher-Price Gearbox? It is a plastic gear with a very triangular profile. It looks like the profile is still an involute but with a pretty high pressure angle. The pitch is either 10 or 12 (I forget at the moment)

Anybody know what it is? Or is this a special profile for plastic gears?

If anybody is interested, I want to make a gear to drive an encoder. So it doesn't have to be an exact match, but the closer the better.

Thanks,

Chris H