This is a puzzle box that I was inspired to make after I saw a few people solve a wooden version of this on Youtube. The puzzle is how to open the box as it has nothing on the outside. It is good showpiece, piggy bank, or storage container for secret things. It would also be pretty cool if used for geocashing. Scroll down for the solution to open this box.
The mechanics are pretty simple and it is easy to assemble. 7 nails and a little glue is needed to complete the project. The nails need to be less than 0.4cm in diameter and at least 6.5cm long. The glue is just for one piece on the inside.
Feel free to leave a comment, post a make, or tip me.
Please do not commercially sell this design.
To solve this puzzle, slide the nails back and forth to loosen them up. Then, using some force, quickly spin the box in a circle. The centripetal force will push all the nails in opposite directions, unlocking it. Then just gently lift up the lid which should freely slide out.
Update: If the nails don't fully slide all the way when spun, spin the box the other way.