[jman4747]

So if I have the tooling and can keep the weight down why not save the money? And if I get 3 times as much free sheet steel wouldn't it just be better to save the money and be smart about its use?

Basically what I'm getting at is it isn't as simple as Steel is denser or aluminum is less rigid. For instance at the beginning of last build I found that a welded steel version of the kit-bot frame we used would be several times more rigid and cheaper. It would only have been about 2-5lbs heavier and that robot was 98lbs at inspection. We didn't posses the tooling to work it quick enough yet so we scraped it.

Witch metal to use has to do with the circumstances surrounding the team and the build.