Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5991653.

made a box cutter balisong a few days ago and figured why not make one of a Exacto Knife. The handle parts are connected by 1.75 mm filament(the hole will need to be drilled out in both the handles and blade holder), which you can heat the ends of with a torch to keep in place. The blade can be held in with any 2mm diameter screw/bolt as long as the head isn't taller than the blade holder.

Butteryfly knives are illegal in Hawaii, New Mexico, South Carolina, and Washington and have restriction is Wisconsin, Utah, New York, and California, so obviously don't print this if your in those places.