Introduction: Three Dial Geared Puzzle Box [gearbox]
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
Materials:
- 4 mm wood (30 x 30 cm)
Tools:
- 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.
Attachments
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.

Participated in the
Epilog Challenge 9
23 Comments
11 months ago
Hi, it is not possible to download .svgz for laser cutting. Could you help me please? Thank you, Michal
Reply 10 months ago
I added a PDF. I hope that one works better.
Reply 10 months ago
But the details on the pdf aren't good enough. Lightburn doesn't recognice most of the lines... )_:
Reply 10 months ago
The cutting lines in the PDF are vectors so it should work in any program. I don't know how lightburn works. You can import the PDF in a program like inkscape, AI, gravit designer or something like that and change the settings to your needs.
Reply 10 months ago
Thank you, it is ready :)
Reply 10 months ago
I'm not sure why it doesn't work. I see the problem. It also doesn't download when I try. I will see what I can do.
Question 5 years 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
Answer 5 years 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.
Answer 5 years 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.
Question 5 years ago on Step 2
we’re would I get a laser cutter from
Answer 5 years ago
Ebay
Reply 5 years 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.
5 years ago
....as if most readers have the tools required for this......
Reply 5 years ago
Huh.
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 5 years ago
Luckily, most makerspaces have :) (the only reason I have one is because I am trying to start a makerspace in my area)
5 years 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!
Reply 5 years 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 ;)
5 years 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
5 years 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.
Reply 5 years 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. :)