My two boys made cardboard string and disk spinning toys at our local Science Museum. Lets just say that my kids ability to evenly put holes in the disk was questionable, so they never really got up to speed. We worked together to come up with a design quick in solidworks, and printed a V2 for them to play with. Simply print out the included model, add some string, and let the learning about centrifugal and gyroscopic forces begin :)

In addition to the STL I have included a STEP, Fusion360, and the native Solidworks file.