[NoodleKnight]

Since its just a demo gearbox, and they're using a polycarbonate, precision isn't that necessary, it just has to work. Even if the tolerances are out of whack, the gears will break-in and all will be well.

And I second sanddrag, gears do look cooler, haha. But that's my opinion, I'd be too lazy to cut plastic gears and just stick to the plastic wheel ideas, maybe put a layer of epoxy or rubber cement on them to increase friction. I mean, it just has to show the shifting mechanism; if anyone is curious about how it does with real gears, just show them your robot =)