Combination Lock Assembly

Combination Lock Assembly Instructions

Please read the General Instructions for Acrylic Models first, then watch the video below.

Be sure to watch this video before you try to put the model together. Make it full-screen using the icon in the bottom right of the video player. And please pay attention to these following updates to the assembly instructions.


Due to an error in the laser cutter file, one of the parts in an unknown number of these kits may have an off-center hole. The problem can be resolved by modifying how you assemble the model, or by asking us to send you a corrected replacement part.

You will find a set of five identical disks about 3/4” (20mm) in diameter with a 1/8” (3mm) hole in the center (or not quite in the center for about 1/200 of these disks made in the past). Three of them are used inside the three code wheels, and must be perfect for the model to work correctly. The other two are used as spacers around the front panel: for those two, slight misalignment of the holes will not effect operation of the model (and will barely be visible).

Please check these five disks and if you find one with its hole not in the middle, just use that one around the front panel. Or if you prefer, send an email to and we will send you a corrected disk immediately.

Note on disk friction

During the assembly process you will encounter three bent washers made of thin polycarbonate. They have intentionally been creased in four places to make them wavy. This creates a controlled, stable amount of friction that makes sure the code disks stay where you dial them in to. However, if the creases are too strong, you can end up with too much friction, making the dial hard to turn, especially when it’s turning all three disks at once. The disks only need to be a little bit wavy: just a touch of friction is enough. So I recommend you press them flat or even un-bend them a little before assembly. If you end up with too much or too little fraction after putting together the code wheel pack, you can easily take them back out and fold them more or less. Because polycarbonate is a very tough material, once assembled they will provide a stable amount of fraction indefinitely.