A couple of weeks ago I stumbled upon some videos explaining how combination locks work and immediately headed to my LEGO collection to see if I could build one of my own. I decided to build a typical 3 number combination lock and incorporate it into a LEGO safe. Check out the video to see exactly how it works. Step by step building instructions can be found below.
Some notes on the construction.
For the ‘numbered’ dial I’m using the printed dish from set 4488 Mini Mellennium Falcon, which was released way back in 2003. There are a couple of other printed dishes that might work, but none of them are all that readily available. I would recommend just custom decorating a regular dish.
Be sure you actually know the combination before fully assembling and locking the safe! I designed this safe so that you can’t just take it apart normally. If you have to break into it you might have to physically break some pieces.
You can actually change the combination by changing where the ‘tabs’ are located on the discs. Using the axles like I have done only really gives you a few options of where to put them, but you can use other parts to create the tabs as well.