Improved 4 Compartment Box with Hingepin

I was having a lot of trouble getting the hinge to work well on this box, so I modified it so that a pair of metal pins could be used to hold it together. The rear top has 3mm holes added to the hinge, and the bottom has a matching 3mm slot.
Due to printer tolerances, I ended up needing to use a 2.5mm rod on my prints as 3mm was too large. 2.5mm fits perfectly for my application and I don't expect it to fall out. You could easily add some epoxy to the slot just for extra reassurance though. Two small pieces can be placed in slot and then tapped into place with another longer piece and a hammer.