Regarding the "Involute Gear" profile thing:
A few months ago I came across that term for the first time, here on these Forums.
I did a little Googling, and quickly came across a web-site created by some machinist/engineer that walked us right through the exact steps of creating an Involute Gear-- complete with animated GIFs.
It was quick, easy, and fun (for the geek in us) to work through. A total Geometry lesson.
I have the TurboCAD drawing-file and the image/PDF somewhere on my system.