The shaft is supported by the two tin-can strips. Fold them in half lengthwise for added stiffness. Then bend about ¾" for the base. Nail them to the wood block, in line with the upright nail.

     You’ll have to decide how high the shaft holes should be. Locate the holes so the magnet ends are close to the upright nail head yet do not prevent the shaft from spinning freely.

     Insert the shaft in the supports till the magnet is directly over the nail head. Two collars of electrical tape will keep the shaft in place. Finally, drill a hole in the propeller so that it fits snuggly on the nail.