Fidget spinner

Design Statement
For this project, I decided to design a functional and printable fidget spinner using SolidWorks. I modeled the main spinner body and two types of bearing caps that could be used for the grip. I worked through the design step by step and fixed several mistakes while they came up. The goal was to make everything printable and cleanly assembled.

1. Creating the Spinner Body
 

I started by opening a new part and selecting the Top Plane.

I sketched a large 80 mm diameter circle which represented the full outer size of the spinner.

Inside the same sketch, I created a three-lobed shape by tracing the sketch picture I inserted

2. Cutting the Center Hole
 

I selected the top face of the spinner and sketched a circle in the center with a 22 mm diameter.
 

This hole is where the bearing goes, so I used Extrude Cut to cut all the way through.
 

The 22 mm size matched the dimensions of a standard 608 bearing.

3. Creating Cutouts for Weights or Decoration
 

I then sketched three 15 mm diameter circles, placing one on each of the lobes.

I used Extrude Cut to cut each of them all the way through.

I used circular Pattern to also apply all these extrude cuts evenly to the other 2 lobes 

These holes were intended either for adding weights or just for visual balance.

4. Making the First Bearing Cap (Snap Fit)
 

I created a new part and selected the Top Plane.
 

I sketched a 30 mm diameter circle and extruded it to 5 mm thick.
 

Then I flipped to the bottom face and sketched another circle, this time 22 mm diameter.
 

I extrude cut it 1 mm deep to form a shallow gap to snap over the bearing.
 

This was my first mistake because the 22 mm cutout made the cap too loose to hold onto the bearing. 

To fix it, I changed the inner diameter to 19.5 mm so it would fit more tightly over the bearing.

5. Making the Second Bearing Cap (Insert Fit)
 

For a second cap option, I created a similar 30 mm circle and then sketched an inner circle of 19.5 mm.
 

I extruded the entire shape to 18.5 mm tall.
 

This was based on a mistake I made earlier: I originally extruded it only to 12 mm, which was too short to grip.
 

After testing, I increased the height to 18.5 mm for a better fit.
 

Next, I extrude cut the outer 30 mm circle down to a depth of 17.5 mm, leaving just 1 mm for the top surface.
 

This formed a plug-style cap with a shaft that fits snugly inside the bearing.
 

I had also in the beginning used 21.8 mm for the inner circle at first, but it didn’t fit the bearing.
 

Switching to 19.5 mm solved that.

Troubleshooting and Errors
 

I initially cut the center of the cap too large (22 mm) which made it slide around. Reducing that to 19.5 mm fixed the snap fit.
 

My second cap’s shaft was too short at first (12 mm), so I increased the extrusion to 18.5 mm and got a better result.
 

I also misjudged the shaft size on the second cap by making the inner circle 21.8 mm. Once I changed it to 19.5 mm, it snapped into the bearing properly.

Final Results
 

I printed the spinner body and both bearing caps separately.
 

Each cap fits the bearing in a different way — one snaps on top and the other inserts inside.
 

Everything was assembled easily after fixing the dimension issues.

Before:                                                                                                    After:

Final Design Choices
 

The biggest issue was misjudging several key dimensions.
 

I originally made the snap cap too loose with a 22 mm hole. I fixed it by resizing to 19.5 mm.
 

The second cap also had two problems: it was too short at 12 mm, and the shaft was too wide at 21.8 mm.
 

I changed the height to 18.5 mm and narrowed the shaft to 19.5 mm, which made it fit properly inside the bearing.

It works!