Super Heavy Metal Spinner

For this spinner, you need to cast metal in a sand mold.

Please note that using lead is problematic, as it is toxic (especially the fumes when melting it). Maybe tin would make a better choice.

The reusable form is supplied with a small handle, it is prepared to make an open mold.
Afterward, some sanding will equalize the difference in weight, so it runs smoothly.

The supplied cap is quite concave; it has to be printed upside down with some support material. But you can, of course, use any other cap for the 608 ball bearing.

I achieved 5 minutes and 13 second spinning time (speed up by hand, no compressed air or such).