[Jared]

I used stainless rod that was somewhat polished to have a smooth shaft that wouldn't corrode in our humid winter climate and brass because I hadn't turned it much and wanted to play with it. I think next time I would use acetal (Delrin) for the rollers because it's self-lubricating and real easy to machine. Aluminum is certainly cheaper than brass and I think it would work just fine. It will wear out sooner since it's softer but unless you're planning on putting a serious amount of hours on it there shouldn't be much trouble. The main thing is to use a shaft material that is harder than the bearing material so you don't wear out the shaft since generally speaking bearings (or bushings) are cheaper and easier to replace. Using the same material for both isn't a good idea. Looking forward to seeing yours and don't be afraid to start a thread.