Permutation Lock

thingiverse

These devices are commonly referred to as combination locks, but they're actually permutation locks - the sequence of numbers truly matters. My 6th grade math teacher pointed that out, and I've always remembered it. Print one copy of each file. The infill of the chassis and top doesn't matter too much (I used 50% for some added strength), but print the wheels and plunger with 100% infill. Currently, there are only wheels for four numbers I randomly selected for my combination: 3, 4, 6, and 8. If this thing becomes popular and people ask me to, I'll add ones for the other digits. Instructions for assembly: 1. Print all the parts. 2. I recommend sanding down the edges of the wheels a bit (there was probably some warping, and they need to be able to rotate smoothly in the chassis). 3. Place the wheels in the slots in the chassis, making sure that all the numbers are facing the same direction. 4. Rotate the wheels so that the spaces corresponding to the numbers align with the slot in the chassis. 5. Insert the long end of the plunger into the hole and through all the wheels. Mark the spot where the wheels can spin freely and the protruding part of the plunger doesn't obstruct them. 6. The short end of the plunger should fit right into the closed tube on the chassis. 7. Rotate the wheels, facing random numbers outward, and pull on the plunger's arc to ensure that the mechanism is working. Unless you're on the combination, you shouldn't be able to pull it out. 8. Attach the top to the chassis with the wheel slots covering the top of the wheels. I used 3D Gloop, but any super glue should work fine. The Permutation Lock is ready! It's pretty sturdy, but I wouldn't use it to lock up anything too valuable. A dedicated thief would be able to break through this thing eventually.