3D Spin Top

The best spin tops have a tip made of a very hard material in order to minimize friction between the top and the spin surface. This design requires a steel ball to be glued into the bottom of the print. One design uses 1/4 inch stainless steel ball bearings and the other 3/8 inch (Amazon has them). By using these and a concave glass lens or mirror surface, you can get spin times over 6 minutes.

Here's a short video showing the top in action: https://www.youtube.com/watch?v=lySgPi_sKsk