pic: 4 Speed CIM Gearbox

[sanddrag]

Originally Posted by DMetalKong

How well does the Delrin hold up. Originally I had planned the plates to be Aluminum, but the Delrin sounds like it would be a neat idea, especially since it would mean less machining.

In some ways Delrin can be more of a pain. Standard drills and end-mills tend to load up when machining Delrin. Even strong flood coolant won't clear it sometimes. We've found a continuous compressed-air stream on the tool is needed. Also, the material often doesn't come perfectly flat from the supplier. This and its inherent flexiness can cause some gear mesh issues. Threads tapped in it aren't particularly strong, requiring special PEM nuts for anything that screws into it. The weight benefits are nice though.

Originally Posted by DMetalKong

Another thing, would it work to replace some of the gears with brass? I heard that brass gears are supposed to work in, providing a better mesh. I am thinking of replacing most of the gears with aluminum/brass if that will work.

Bad idea. Steel gears will mesh just fine. Throw another .0005-.002" between their nominal center-to-center distance to make sure of it. In my opinion brass is far too weak and soft for applications in FRC drivetrains.

Aluminum gears can be quite successful if done properly. It is A LOT of work though, and requires a very specialized and dedicated sponsor shop. The 968/254 gearbox from 2007 is a fine example. Read about it here.