Construction was by forming it over a tin can, which had a round piece of cardboard on top to provide a backing surface for cutting the fins out with an X-acto knife. The bearing is a slightly raised bump in the foil, riding on a steel wire that was sharpened on the end with the grinding wheel on a dremel tool. The wire is bent into a shape that clips over the light bulb.
It worked nicely when used in the open. But the white plastic globe diffused the light to such an extent that the beacon effect was hardly visible, and due to restricted air circulation it rotated very slowly. Still, it looked a little strange and I left it inside the globe for a while. It worked for a week or two. Eventually it stopped rotating.