I'm impressed! Making each tooth a group is an interesting idea!
Is there any chance you would be willing to add something to deal with gears where the depth doesn't match the diametral pitch? I would be happy to make a PayPal donation to help this along! My specific application is Hardinge change gears. For some reason, they decided to use 20 degree pressure angle, 22 pitch gears, but with a gear tooth depth corresponding to 29 pitch. The technical description is as follows:
Fellows 22/29 Stub Pitch, 20 Deg PA, .003" to .004" Backlash
Diameter over wires includes allowance. For backlash and odd number of teeth. Use two .0785" wires for checking over teeth.
Face Width - .370" / .375" Bore - .625" / .6265" Keyway - .125" Bore to top of key - .693" No Heat Treating
Note: The 22/29 stub pitch has the pitch diameter of a 22 DP gear (N/DP). The tooth depth is that of a 29 DP gear. Whole depth is 2.25/29=.0776". The addendum is the tooth amount above the pitch line (1/29)=.0345". The Std. OD is, PD plus two addendums (n/22) + 2(1/29). Hardinge gears are .005" less than std OD.
Here's a description of the Fellows Stub tooth form:
http://books.google.com/books?id=x2GThADLN-sC%26amp;pg=PA31%26amp;lpg=PA31%26amp;dq=stub+pitch+gear%26amp;source=bl%26amp;ots=6aF1puqw8N%26amp;sig=QOR5ORl4NdVsN3vc7_6eZ6G-Qwc%26amp;hl=en%26amp;sa=X%26amp;ei=SjinUsSaN8P7kQeI1YGABw%26amp;ved=0CBgQ6AEwAA#v=onepage%26amp;q=stub%20pitch%20gear%26amp;f=false