[sanddrag]

This Ultra-Lightweight gearbox was the undergraduate senior project of manufacturing engineers Travis Covington and Kirk Oden at California State Polytechnic University. They are the experts on it, but I'll explain as best as I can.

The gears all started life as several-foot lengths of 7075 and 7068 bar stock, obtained from a local supplier. Dozens, perhaps hundreds of hours went into their fabrication: slicing and machining blanks, hobbing teeth, pocketing for weight, etc. The hard annodizing with Teflon impregnation was a proprietary process done at a local sponsor. It achieved a surface hardness of approximately Rockwell 50 C.

This year, we designed a similar gearbox (using steel gears) which included the Fisher Price motor as well. The difference was substantial. However, we eventually removed the Fisher Price from the drivetrain in order to use in the elevator, and moved the Banebots 550 (previously in the elevator) to the roller.

In two previous years we competed with a 4 speed transmission. While it was neat, we did not find it terribly useful in the rather small playing field (especially given the increase in cost and fabrication time).

We now try to use as many AndyMark gears as possible to save time and money. We still use some Martin gears when we can't make the design work with the tooth counts AndyMark stocks.