Gyroscopic Exercise Ball

This is my take on the venerable Dyna Bee gyroscopic exercise ball that came out in the late 1970's. It uses 48 pennies (US) as the flywheel mass. As a twist, I've added a geared zip starter to get the rotor spinning up to speed. From there, you keep it going with pure wrist power.Aside from the 3D printed parts, you will need a 0.125" diameter steel rod and some superglue to put it together.UPDATE: I've modified the shell to make it easier to align the zip starter with the slots in the side.Print SettingsPrinter:UDIORafts: NoSupports:NoResolution: 0.2mmInfill:20% Notes: Print to two of the shell.STL, two of the rotor.STL, one of the ring.STL and one of the gear.STL. I've included two versions of the rack.STL (the zip starter) - one about 11" long and a shorter one about 7.5" long that should fit on a 250x250mm print bed. You will also need a 0.125" diameter steel shaft (available from most hardware stores) that is 2.465" long, and also 48 US pennies, preferably new.Post-PrintingAssemb