The rear of the machine shows the hand crank that is built similarly to the top shaft: 1/2" aluminum rod run through the frame that is bushed with brass tubing. The lower drive shaft has two wooden pulley on it that I also turned out of cherry. These pulleys have a v notch cut into the edge to track the rubber drive bands. The pulleys have a small wooden hub screwed into the SIDE of the pulley which the hub has a insert in it where a screw runs through it and grips the shaft. File a small flat on the shaft to help land the screw.
Note that each of the leyden jars exterior aluminum foil surface is bonded to a brass strap which in turn is bonded to the other jar. This grounds the two jars exterior to help draw in charge to the internal foil surface. I used a very thin film of rubber cement in the jar then smoothed the foil onto it with a smooth wooden stick. Pre-cut & test fit the foil forst and pre-smooth it before fitting it inside.