Lol. Is anything ever REALLY finished?
About the program, personally I'm not concerned about it being easy to understand. I just want something I can use to run my machine and that has some provisions for customizing the setup. My only special request would be to have provisions for plugging in code for the Adafruit motor shield and possibly some "step and direction" code to interface with common commercial stepper drives.
I've been meaning to ask, is there anything I can do to help support your efforts? Obviously you've put a lot of work into this project and, as a beneficiary of that work I would like to contribute. I noticed a link for contributions on your home page. Are cash donations preferred, or would some custom gears and/or mechanisms be more useful? My little Taig mill and lathe are pretty handy for that kind of stuff.
The pinion gear in the photo is made of Delrin (a.k.a. Acetal) plastic. Turns out that this sample was cut too deep so didn't work very well with my current shaft spacing. I think the key is to make the circumference of the blank evenly divisible by the number of teeth desired, and then advance the tap into the blank by a distance equal to the depth of the worm screw threads. Originally I thought that the "pitch diameter" would be less than the outside diameter, as it is with regular spur gears. In this case however, the first pass "locked in" the tooth count, then as I went deeper and the circumference decreased the bottom of the threads started overlapping. If you look closely at the pic, you can see a good tooth profile on the sides of the "groove", and the threads getting real thin at the bottom. The good news is that almost anything will work, but if you want accurate control over the tooth count and shaft spacing it takes a little planning.