I made this hamster spinning wheel from an Ikea plate, 3D printed parts, a carriage bolt and a bearing from an old fidget spinner.
Our hamster runs 4.5 km a night
Step 1: 3D Print and Assemble the Base
I printed the base in PLA with an 0.8 mm nozzle on my Wanhao Duplicator i3. Assemble the base with 2 screws. The bearing should fit in precisely.
Step 2: Prepare the Plate
Drill a hole in the plate of 8 mm. Cut it square with a knife, so the 8 mm carriage bolt fits in fine.
The plate is separated from the bearing by a 3D printed ring.
Step 3: Assemble the Spinning Wheel
Assemble the wheel by mounting the bolt and fix it with a nut.
Step 4: Let Your Hamster (and You) Have Fun
If the wheel spins too fast, you can slow it down by fastening a tie wrap around the separation ring, so that it makes contact with the bearing.
You can fix in the cage by using some rubber adhesive footpads.