A great online gear generator
For anyone who finds themselves needing to generate cut patterns for gears on the go, I highly recommend this wonderful dynamic site created by Abel Vincze of Iparigrafika Ltd: Geargenerator.com. You can make one gear, or half a dozen gears. You can animate them. You can also turn around and download the vector pattern as an SVG.
It's just great. I have used it for a few hobby projects that involve 3D printing spur gears. The tool lets you create systems of gears that mesh very nicely. Thank you Vincze for making this awesome tool available, and for free no less!
If you liked this awesome free tool, I highly recommend visiting another tool he has created: HTML Spirograph. It lets you generate beautiful spirograph images by tweaking various parameters.