A sliding ratchet (vehicle toolkit) I already had one but if you don't you can purchase on for about $25 on ebay:
2 metal poles I found inside a printer
2 alligator clips a big one and a small one for small and fragile pcb's
Screws (so the box won't fall down under the weight of the pcb's. I put 1 kilogram [2.2 pounds] of random screws I had in each box)
Everything was hot glued and surprisingly it's strong enough
If you want to see more of these kinds of projects make sure to check out my instructables page and subscribe :)
chrisjlionel made it!