Yes, this is the craze of 2016 and the craze of 2017 combined in one beautiful nonsense. :)
You will need:
-A precise printer (preferably 3D)
-608 bearing (whatever type you prefer)
-three M8 nuts
After printing all the parts (the hemispheres WITH support) just insert the nuts, the bearing and the bearing caps. They should friction fit nicely. Glue the hemispheres to the body with superglue. There are two spinner bodies with slighly different size. Use the one, that is more confortable for your hand.
Happy spinning! :)
*Leaning back and waiting for 'I choose you!' comments.
Mechanical engineer | Maker | Master procrastinator | Professional 3D printing enthusiast at @freedeeprinting | Full time Star Wars fan