Weapon mounting

We need a way to build and mount a bar spinner, which is light, and something we can make with primitive tools (sadly we lack lathes etc), we have been looking for bearing hub on the Internet, but haven't come across any thing usable, we also need to make the bar to fit to it, we were going to use 2 12mm teeth bolted to the out side of each end of a 6mm bar, but we haven't got any idea how to mount it, Any help would be good, as this is the last few days we have to work on it before the event. Thanks!

Scrap that, were just going to use a 10mm (ish) plane bar, mounted to a hub out of an old small wheel, and then bolt the pulley to the out side.