Tri-Spinner

I used a 5/16" hex nut and a 608 long board bearing. They are a tight fit and I had to hammer them in. I haven't had any problems with the nuts coming out. The bearing is greasy and will slide out if you use it a lot or get rough. You might clean the grease off of the outside to help it stay longer, but I just used the Simple Bearing Cap from Very Customizable Fidget Spinner to make it easier to hold and to keep your fingers grease free.