[EricH]

Originally Posted by helgy8

maybe, maybe not. instead of questions, any ideas?

The reason we ask questions is so we can help you better.

If you have something like delrin available, you could conceivably make a ring out of that, though I don't know how tough it is to move delrin (which can be fairly slick) against other plastics, like PVC.

You could also, instead of compressing the balls, use some form of bristles to move the balls up. This has been done before, and it will eliminate some other concerns that have been brought up. If you have the 2006 Behind the Design book available, look at team 694's entry.