Three Dial Geared Puzzle Box [gearbox]




About: I'm a social-worker, working with 12 - 23 year-olds. I used to be a printer. In 2018 I opened a small makerspace ( in my house, where I have lasercutters, 3d-printers, Arduino's, Mindstorms and ...

Being a little addicted to my Trotec lasercutter, I had to design a puzzle box.

This box has three dials, connected with each others with gears. The middle gear is missing two teeth to make it possible to scramble the code.

To open it, you first need to know the code and than you need to manage to enter the code. When you turn one dial, the next one will turn in the opposite direction at an other speed. When the two missing teeth are at the next gear, you can turn it freely to scramble the puzzle.


Step 1: You Will Need


  • 4 mm wood (30 x 30 cm)


  • Lasercutter
  • Wood glue
  • Clamps

Step 2: Lasercutting

The design is to fit on a small piece of material.

The red lines are cut lines and the black is etching.

Step 3: Start With the Gears

  • Glue the the part with the big rounded hole on the bottom of the marked top piece with the tree holes.
  • Glue the round pieces on the marked circles on the gears.
  • Glue the half circles that are marked with the small gears on the small gears accordingly.
  • The two other half circles can be glued to the markings on the back of the big gear.
  • Put the discs on the gears in the holes on the top plate.
  • Glue the two pieces with tree half holes on top of the gears. (don't glue the big gear stuck)
  • Glue the three dials on top of the round disc. Be sure that the slots on the back are all lined up and put the disc in het position that you want the puzzle to be solved. (in my case that is 10 - 10 - 10)

Step 4: The Box

  • Glue the inner drawer together. (be sure to put the indentations on the outside)
  • Glue the four small studs in the in the indentations.
  • Glue the three sides (bottom and sides) of the outside together, using the drawer as a template.
  • Glue the finished top on top. (take care not to glue the drawer stuck)

Step 5: Start Puzzling

  • Put some talcum powder inside if the gears are hard to turn.

Turn the two outer dials in the same direction, and the middle dial will turn in the other direction slower.

At one moment you will feel that one of the outer dials can turn freely. This is to scramble the puzzle.

After the scrambling of the puzzle it is hard to open it again, even if you know the code.

What would I do different next time:

  • A little more teeth would make the puzzle even harder.
  • The design should have a little more room for the gears, drawer and studs to move smoothly.



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    17 Discussions

    Waste Of Space

    Question 1 year ago on Step 2

    Would you please supply this drawings as a DXF.
    I have a lot of difficulty changing the SVGZs to DXFs.
    Thank you

    2 answers
    Waste Of SpaceWaste Of Space

    Answer 1 year ago

    I too use Inkscape for some things, but the drawings will not import into the lasers RDworks program unless they are in the correct format. This being so, it is a long and tedious job to change the drawings to a DXF format and the DXF format that Inkscape exports to is not a standard one.

    kenyerWaste Of Space

    Answer 1 year ago

    I simply use Inkscape and SVG is the default format for Inkscape. You can probably use Inkscape to export it to an other format.


    Reply 1 year ago

    That depend on your budget. The most affordable way is to use one for free at a makerspace or fablab. If you want your own, you can buy them from alibaba from around a 1000,-. If you have more to spare, you could try glowforge (but they are still not delivering outside the US) I bought mine second hand and fixed it up for 'only' 4000,-. And I do understand that that is much to much money for most people. That is why makers can use my lasercutter free of charge.


    Reply 1 year ago

    Sounds like a "not nice" comment from someone who expects hand tools only.
    Kenyer, you answered with grace and a smile. Good for you!


    Reply 1 year ago

    Luckily, most makerspaces have :) (the only reason I have one is because I am trying to start a makerspace in my area)


    1 year ago

    Very cool instructable! I'll add it to the list of things I'd make, if I only had a laser cutter :) Nice job!

    1 reply

    Reply 1 year ago

    I'm developing a Makerspace in my area to solve that problem for you, so when you are near "De Hoekse Waard", let me know ;)


    1 year ago

    I have an older Universal 40 watt laser engraver. I'll tackle this project tonight after I get home from work. Thanks for the project! Ed in Columbus, Ohio


    1 year ago

    I think some edits are in order starting with the title.
    I believe you mean to say "three" not "tree" in the title as well as throughout the instructable. You misspelled "dial" in the title. With these two errors in the title I wasn't even sure what it was describing. Just trying to help.

    2 replies

    Reply 1 year ago

    Thank you. I wasn't sure about the tree, but this was google-translate's suggestion. Being Dutch and dyslexic, word like that are always hard for me. :)


    Reply 1 year ago

    Looks great now! Good job.