This is a fidget nut spinner that you print in place, with the spinning wheel captive on the nut. There is a part at the bottom of the center part without threads, this aids in printing as well as allowing the center wheel to free spin when it reaches that point. The threads will wear down as you use it, making it spin easier and easier. But if you want, you can take a little light sand paper to the threads to loosen up things even more.
The wheel is printed with 100% infill to give it momentum as it is spinning. The center has 6 walls to improve strength of the threads.
Enjoy.