Customizable Permutation Lock Kit (Combination Lock)

cults3d

When I'm designing a functional model like this, Autodesk Fusion 360 is my go-to CAD software—the dimensional accuracy and mechanical features you can achieve can't be beat. Get it here! (affiliate links) These are usually called combination locks, but the numbers you have to enter are really a permutation–the order of the numbers DOES matter! To create your own customized permutation/combination lock, first choose a size (3, 4, or 5 digit passcode) and the actual permutation you want to use (e.g. for a 3-lock, 2-7-4). From the files, print one (1) each of the top, bottom, and hook of the size you chose, as well as the wheels for the numbers you want. Fit the wheels into the slots, place the two halves onto each other, and attach with either a M3x20 nut and bolt or superglue (make sure not to get any glue on the wheels–you won't be able to spin them if you do!). Both a bolt and glue would make the strongest lock. When you rotate each wheel so the digits of the permutation you selected face outward, you'll be able to slide the hook into the assembly; when it's all the way in, change the digits so they don't match your permutation and the lock will be secured. Keep in mind that it's made of plastic: it probably isn't sufficient to protect anything really valuable, though if you use PETG or another strong plastic it would be pretty difficult to break. That's it! Make as many as you'd like in a variety of sizes. Please share feedback or results.