I am building a large "spin and win" like device consisting of a frame and two spinning wheels, with the smaller wheel in front of the larger one. The axel for these wheels is a 3/8" carriage bolt that is 6" in length. The frame and each wheel has a 1/2" hole to accommodate the axel and a steel sleeve. The sleeves serve two purposes: reducing friction when spun and protecting the plywood from being damaged by the threads on the bolt that serves as the axel. Nuts behind the frame and in front of the frame allow for adjusting the forward position of the axel on the frame.
The wheels spin smoothly and easily. The problem is that spinning the wheel causes the wheel to rub against the washers and nuts that hold everything in place on the axel and, depending on which way the wheel is spun, will either tighten the nut to the point where the wheel cannot spin or loosen it to the point of wobbling.
I don't know how to solve this. I've tried using two nuts tightened against each other and that didn't work.
I'm open to suggestions.
Edit: It is a set piece for a show so it needs to be able to easily disassemble and reassembled.