In this project video I'll show you how I've made a stacking ring in Autodesk Fusion 360. Old caps could be very useful to store small items like LEDs, nails, screws, wires, batteries and more. Unfortunately these peanut butter caps didn't stack very well. When stacked they slip off each other. With this stack ring they caps stack perfectly. I've printed the ring in black PLA on my Wanhao i3 3D printer. After printing I glued the ring on the cap.