Folding Pen Gift Box

Wanted to give out some beginner fountain pens and a few pens didn't come with fancy boxes.  I found a model or two that I liked, but they weren't free, so here we are.  This unfolds to display whatever cylinder shaped object you happen to place into it (UP TO 15mm DIAMETER).

This design can be improved with the addition of a felt lining in the cradle part and on the backside of the lid if you are putting something fancy in there and don't want it rattling around against bare plastic.

I also uploaded the FreeCAD files that can be modified to accommodate additional diameters or lengths (larger or smaller) AND so people can add their fancy designs to the outside of the box or make changes to the native files instead of having to reverse-engineer anything. 

I like printing in the orientation in the screengrab.  There are no supports required if you have your printer dialed in and print inside walls before outside walls.  I used 3 walls and 15% gyroid infill for the photographed examples if you were wondering.  The surface finish comes from my textured PEI build plate.  The hinge pins (there are 2) are just a piece of un-printed 1.75mm filament.  I recommend gluing at least 1 end of each hinge pin in place otherwise they start to work themselves out of their holes.

I also recommend print these from ABS; there is some really interesting PLA, but it won't hold up if you forget this box in a car on a hot day!