I am part of a DARPA Robotics Challenge Team Track D that has been accepted for the December 2013 Qualifications. Derived from http://www.thingiverse.com/thing:53451 but there are parameters that allow you to explode the gear and slice the sun into two pieces. This allows us to "fix" a busted gear more easily without printing an entire bearing. Though printing a working gear in one print always impresses people. See it in action in videos at out youtube channel. http://www.youtube.com/mojavaton and http://www.mojavaton.org Thanks to thingiverse for inspiration and resuable designs. Team Mojavaton