Posted by Kimbrough on October 08, 2005 at 12:32:48:
I'm a mentor for a high-school robotics competition, and we need to make some gears out of wood. (Yes, wood - competition requires using only the official provided materials.) The school shop has a plasma cutter that will cut a pattern from a CAD drawing. We could use this to make a metal template to guide a wood router. Typical gears for our robot projects would be roughly a two-inch gear with eight big teeth, with a matching rack gear that would allow us to drive an arm back and forth. Another possibility would be some gears, again a few inches across with just a few teeth, that give small reduction ratios, like 3:1 or 5:1.
Are there any public-domain or cheap CAD drawings of such gears that I could download somewhere?