This display is optimized for standard challenge coins with approximately 1.759in or 44.68mm diameter.
An oblong sphere shape is arrayed around the edge of the pocket to provide a soft interference fit around the coin, while still being easy to press in and remove.
Each holder dovetails into the previous one, and a plug covers up the dovetail at the end. At the back, there is also a spherical key for security and alignment.
I printed these face down to take advantage of the textured PEI surface pattern, which has some trade-offs for supporting the dovetail features, and I optimized the tolerances for this print method. Please let me know if other orientations or layer thickness require wider tolerances.
The author marked this model as their own original creation.