pic: Inverted CIM 2-Speed Gearbox

[cbale2000]

Originally Posted by Chris is me

I wouldn't do either of those things, especially since you are cantilevering the first stage. You don't want the extra flex that these materials will add to your gearbox. Spend the few ounces of weight where it matters; I guarantee you something else will be on your robot that you would rather cut weight from than your gearbox plate. If you really want to minimize gearbox weight, pocketing the gears is where you could start shaving a few ounces.

To clarify my previous comment, you CAN use polycarbonate for gearboxes generally speaking, but you would probably not want to use your current design if you went this route.

A quick redesign using solid (not pocketed) plates and eliminating cantilevered shafts (by simply supporting them on both sides) might still be a worthwhile weight savings.