Originally Posted by Kevin Sevcik (Post 1160870)

It's interesting that you did that to lighten up some AM Toughboxes, since the TB back plate is polycarb (Lexan) and the front plate is 1/8" aluminum. And AM will sell you aluminum spacers as well.

At any rate, 1/4" Lexan will be about 10% lighter than 1/8" aluminum, for starters. If you're not direct driving out of the gearbox, 1/4" Lexan will be plenty strong enough. The main downside to Lexan is that it's prone to cracking. Not as much as acrylic, but much more so than aluminum. So you'll want to be careful about tightening things and subjecting it to heavy shock loads. There's a reason AM chose aluminum for the front plate of the TB, that's the plate that takes the most load from radial forces on an overhung shaft.

Since 1/4" Lexan only saves 10% over 1/8" aluminum, perhaps you should look elsewhere in the TB for weight savings? AM will sell you aluminum versions of the large gears that will save you 0.56 lbs together. In the past, I've tossed the large gears on a CNC and webbed them to save a similar amount of weight. And there's the aluminum hex output shaft that would save you another 0.1 lbs or so.

So what I'm basically saying is that if all you did to lighten up a TB is custom side plates and spacers, then you have some other low hanging fruit available.

Originally Posted by Joseph Smith (Post 1161028)

So, reading through these replies, it looks like most teams either stick with aluminum or have the plate closest to the motors polycarbonate (or delrin) and the other plate aluminum. The general consensus seems to be that you can easily remove weight by changing your gears (switching to aluminum or milling out the steel ones.) This is probably what we will try next year. Has anyone had problems with the aluminum gears, or milled out steel? I would like to avoid any stupid rookie mistakes :)

Originally Posted by Gray Adams (Post 1160983)

We have a gearbox this year that is one side 1/4" delrin, other side 1/4" aluminum. We pocketed the aluminum plate out and it weighed almost the same as the delrin. It really doesn't seem to be any better not to use aluminum, and the aluminum looks a whole lot nicer after bead blasting and anodizing. In fact, the delrin was a little bit warpet because it was such a large piece (9"x 6" I believe). We only used delrin because we mounted Banebot 775s to it and that way we didn't have to worry about the cases shorting to the frame.

Originally Posted by MICHAELABICK (Post 1161071)

Please do not do this. It WILL NOT SOLVE YOUR PROBLEMS. The case will still short, just through the metal gears instead. You most likely got lucky with your 775s

Originally Posted by Hawiian Cadder (Post 1161112)

You could use Plastic gears out of a FP Gearbox to help with that.

Originally Posted by Cory (Post 1161044)

We have been pocketing steel gears since 2004. Never had a failure.

968/254 used custom aluminum gears in 2007 (some pocketed, some plain) with no problems.

Same thing with WCP aluminum gears this year.

Originally Posted by Joseph Smith (Post 1161208)

When you pocket steel gears, do you mill them out in a spoke shape (comparable to the aluminum performance wheels you can buy at AndyMark) or do you just drill holes out of them?

Originally Posted by Cory (Post 1161211)

We drill holes and then pocket a step on each side with a .125 radius at the edges,leaving a web thickness of .075" if i remember correctly.

Originally Posted by MICHAELABICK (Post 1161071)

Please do not do this. It WILL NOT SOLVE YOUR PROBLEMS. The case will still short, just through the metal gears instead. You most likely got lucky with your 775s

Originally Posted by Hawiian Cadder (Post 1161112)

You could use Plastic gears out of a FP Gearbox to help with that.

Originally Posted by squirrel (Post 1161130)

we made our own mechanism gearboxes using older FP plastic gears and polycarbonate side plates. Very easy to make with minimal shop equipment....