Artist Aaron Kramer created this great video in which he shows us the inner workings of one of his kinetic sculptures. Along the way, we learn a lot about how to make a set of pinwheel gears.
From Aaron Kramer:
I had always wanted to make a piece that contained a pinwheel gear made from wood and metal. These gears are the kind you would find on an old windmill. They seem pretty simple but are tough to get right. Starting with the tin can base and half an idea I first needed to make a set of working gears. I used Adobe Illustrator to generate my own templates. Transferred them to wood disks that I cut with a hole saw.
The method using Adobe Illustrator is covered in Cabaret Mechanical Movement: Understanding Movement and Making Automata.
If you don't happen to have Adobe Illustrator, you can also use an online gear template generator. I explain that process in an article on Making Pinwheels Patterns.