This is an idea I had for printed-assembled, reversible hinges. I started with HingeBox Printable As An Assembled Unit Without Supports by profhankd. I cut off the hinge section from the source STL file and remodeled it in SketchUp using his design as a guide. My hinges are actually double hinges or can be thought of as links between two rotating plates.

In my first test, the links were very thin. The resulting hinge was floppy and the two sections are able to twist, because there is nothing keeping the links parallel.

In the second test, I removed a link and made them about the same length as the solid sections of the plates. This hinge was much more stable and the twisting was almost gone.

In the third and final test, I made the links as long as possible, and the solid sections of the plates very thin. In order to do this, I had to flip the conical pins and hollows within the hinges. This hinge was the most stable of the three and to me it is the most aesthetically pleasing.

Let me know if you end up using these in any of your projects!