Wankel Rotary Fidget Spinner

Update 8/9/22: Added STEP files for anyone who would like to more easily modify the design. 

I liked the original but I found that it would bind up occasionally. I thought a bearing would help keep it smooth. I have a ton of 608 bearings leftover from the initial 3D printed fidget toy craze a couple years ago, so I figured why not. 

I modeled the housing and everything from scratch, researching the geometry that defines a rotary engine (known as an epitrochoid) was fun. I used an equation driven curve in CAD to draw it. 

The bearing should be a light interference fit in the housing (I popped it in with my hands). Slide the eccentric shaft into the triangle and line it up into the bearing. Using the bearing retainer and a M3x10 flat head screw, fasten it all together.