This is a medium duty hinge I developed as part of an enclosure I'm building for my Prusa i3. I use a lot of 1/4"-20 bolts, so I used this size for both the hinge pin and fastening holes in the current STL. I also used a hinge size of 30mmx30mm for each side (with some extra for the captive nut on the hinge pin).

This part is parameterized (via OpenSCAD), so you should be able to adjust the hinge, fastener, and pin sizing to your heart's content.