Magnetic puzzle box geocache

I designed this puzzle for a geocache. It's heavily inspired by RWReese's design, and it opens the same way; you have to smack the puzzle to get ball bearings to jump from one magnet to another, unlocking the cache. Once unlocked, it slides open to reveal a standard "bison" container which holds the log sheet.

The base of the puzzle has six rare earth magnets so that it can be directly stuck to a metal surface.

You'll need:

• Eight 3/8" x 1/10" rare earth disc magnets (I purchased mine at Lee Valley, part #99K32.03)
• Two 3/8" steel ball bearings (I bought steel slingshot ammo from Canadian Tire)
• And glue to permanently attach the magnets in place (I used two-part epoxy)

Make sure the holes are clean - the magnets should sit flat in the bottom of the holes, and the ball bearings should freely move in the holes without sticking.

When gluing the magnets in place, be careful not to get any glue on the sides of the holes that might cause the ball bearings to jam. I suggest sticking the two halves of the puzzle to a metal surface, to keep the magnets in place at the bottom of the holes when the glue dries.

OpenSCAD design file is attached. Enjoy!