I recently watched Adam Savage on the Tested YouTube channel make a replica of the Demon Core Box and wanted to make one for myself (with 3D printing). I printed everything in PLA except the core itself, for that I used some PETG because I wanted it to stand out. I have cut the main body up to reduce supports and I found that you can use the two long bolts to align everything for gluing. 

Be careful screwing in the plastic bolts, they can be fragile. You can also use real ¼-20 bolts if you have them.