[Retired Starman]

My team was very successful using bicycle chain on our arm last year. I went to a bike shop, got the shop to "sponsor" us and give us some old sprockets from their used parts pile. They come with holes for mounting, but no hub, so I cut aluminum disks to bolt onto the sprockets, them machined a hub to attach them to the axles.

I use machinable shaft collars from McMaster-Carr to make easy hubs. I bore them out to the shaft size, then drilled and tapped a couple of holes to attach to the disk I'd mounted the sprocket on.

Bicycle sprockets come in a large range of sizes, are much lighter than 25 or 35 size chain sprockets, are pretty strong (don't know how they would do on a drive system), and easy to come by.

Dr. Bob

Chairman's Award is not about building the robot. Every team builds a robot.