Introduction: Secret Enigma Box

About: Having fun creating more or less stupid stuff

This box contains hidden mechanisms that prevents from opening it without finding clues on its faces to solve it.

At first the box only consists of four cursors that have to be positioned properly and two other cursors that cannot move, but if you look more closely you'll alo see a key hole and two strange rectangles on the sides.

To open the box you'll have to decipher it by looking at the engravings and finding some hidden parts to get new clues. Two codes are to be found in the proper order to open the box.

So far it takes ~45min to people to firgure out how to open the box

Step 1: Materials

To build this box you'll need these things :

  • 4 springs Ø5.5mm , 17.5mm long
  • 2 springs Ø6.5mm , 10mm long
  • MDF sheets 3mm thick
  • MDF sheet 6mm thick (can be replace by two cuts of a 3mm thick wood)
  • Wood glue
  • Sandpaper
  • Masking tape
  • Wood varnish
  • 1 lock + key
  • Laser cuter
  • Felt fabric (optional)
  • Epoxy glue
  • Clamps
  • Hinges
  • Wood chisel or cutter (optional, for fine tuning on sliding stuff if necessary)

This box contains all the necessary springs. They're not the exact same sizes as mine but they should work.

These clampsare a must have generally speaking when doing wood stuff.

This masking tape should work to protect wood before cutting/engraving

This adhesive felt will be perfect for the inside of the box.

Here is the epoxy glue i used.

Grab the hinges you like the most (here for example), the nailed plate shouldn't be more than 6mm long.

I used cheap wood chisels that worked nice for fine tuning here and there.

I bought the lock/key on a local store because i was unable to find a suitable one online. The main requirement is that it should be equal or less than 9mm thick. Mine is 9mm thick, 40mm long, 36mm large and the deadbolt (the part that slides when turning the key) goes 8mm outside the lock (souldn't go further than 10mm without having to move the drawer). This part is clearly the trickiest if you want to build your own box. I'm thinking of a 100% lasercut lock system but for now you'll have to deal with that constraint sorry.

About the laser cuter, i own a Glowforge so the parameters i'll give will be for this specific lasercuter, but any other lasercuter will work, you'll just have to figure out the parameters by yourself. because renting a lasercuter depends on the amout of time you need it, as an indication, cutting + engraving took me around 3hours on my glowforge.

Step 2: Lasercuting Parameters

As explained before, i own a Glowforge, so the given parameters will be for this specific lasercuter.

First, i covered the MDF with masking tape to avoid burnt smudges due to the venting system of the laser cutter. Be careful not to overlap tape bands, particularly over the engraved parts as it would fade them slightly off.

The design contains 4 different engraving colors and 2 special engravings. Here are the parameters i used:

  • Red: speed=1000 - power=60 - Lines per cm=180
  • Orange: speed=1000 - power=50 - Lines per cm=180
  • Light orange: speed=1000 - power=45 - lines per cm=180
  • Yellow: speed=1000 - power=40 - lines per cm=180
  • Key shape: speed=500 - power=full - lines per cm=90
  • Grooves: speed=700 - power=full - lines per cm=90

The grooves are the engraving at the back of the top face. They're used to create "steps" on the sliders. The sliders inside the box have waves at their top matching the grooves. This way when moving the cursor they will more naturally stop at specific positions.

The key shape engraving allows for the key to be lower in the drawer and not cramp the main drawer's opening.

Cutting parameters are just the default one for "Medium Draftboard" material when cutting 3mm elements, and "Thick Draftboard" for 6mm elements.

Only cutting exception with the Felt Fabric. Mine is really thin, here are the params i used :

  • Custom material: 1mm
  • Focus height: 1mm
  • Speed: 500
  • Power: 65

I put bellow the Illustrator file with everything needed inside, from shapes to isometric views !

I also put an .SVG export of the .AI file for people that do not haveIllustrator, but please note that formatting is broken (no artboard, no dark background, et..)

Step 3: Cutting Lid Layers

Right under you'll find the 5 layers composing the lid.

Just cut and engrave them with the parameters explained on the previous step.

Only one specific action with the 5th (top) layer that has to be engraved both sides. I made it so it's perfectly simetrical which means that you can first cut/engrave one side, then flip the cut part at its exact same place and do the second side (as shown in the pictures above). To be sure the holding part don't move i added magnets to fix the MDF on the honeycomb bed.

You'll also want to smoothen the grooves with a wood chisel or the sliders might be really hard to move.

Small warning, don't throw away the center hole of the 5th layer ! It will be used as a pin holder that will act as the button to open the main drawer !

Step 4: Pro-tip : Cleaning the Masking Tape

Cleaning the masking tape can be a bit annoying because of the engravings. The most part can be removed easily but for the small parts you can use some strong tape to remove them.

Just press the tape on the small remaining parts and they should attach to the tape.

Step 5: Lid Assembly : Layer 1 + 2 + 3

Simply glue the 3 bottom layers together with wood glue.

Be as precise as possible, the more precise you are, the better it will work later !

The 3rd layer is composed of 3 main parts but also 3 small rectangles that will need to be placed precisely to avoid slider from blocking. The easiest way is to first place all the sliders in their holes, and glue the spacers inbetween as shown in the picture above.

Maintain the glued parts together with clamps and let it dry as long as your glue requires it.

Step 6: Main Drawer Assembly

Cut and engrave the 3 main parts of the drawer on a 3mm wood.
Cut the locker on a 6mm wood (or twice on a 3mm and glue both together)

Glue the 3 layers together carefully and insert the locker on the hole. No need to glue it but it costs nothing to do so.

Finally, sand the bottom of the drawer to remove the equivalent of about 0.25mm. This is very important ! The drawer's sliding hole is 3mm * 3 (9mm). If the drawer was the exact same height then it will have huge troubles sliding. That's why it's necessary to reduce its height by sanding it.

I personally added some Felt fabric on te inside of the drawer. I put the laser cutting map of it bellow as well.

Step 7: Secondary Drawer Assembly

Cut and engrave the "secondary_drawer.svg" elements on a 3mm wood.

Cut the "secondary_drawer_handler.svg" on a 6mm wood (or twice on a 3mm wood and glue them).

Glue the 2 layers of the drawer together and add the handle to it on the hole.

No need to glue the slider with four bumps to the drawer, it will attach on the side of it.

Finally, same as for the main drawer, sand the bottom of it as much as possible (but not too much !) in order to get it sliding properly later.

Step 8: Sliders

Simply cut the files below on 3mm and 6mm woods.
I added the index of the sliders as engravings to be sure not to place them in the wrong order inside the box, which would kill the possibility to solve the box.

Step 9: Placing Drawers and Sliders

Place all the sliders and drawers on the layers you assembled before.

You don't need to place the springs yet, they'll just need to be placed before adding the 4th payer.

Add the 4th layer without glue and try to make the drawers slide while pressing the 4th layer on them to make sure they will slide properly once glued. If they don't slide easily, sand their bottom a bit more.

Step 10: Adding 4th Layer

Glue the 4th layer.
Pro-tip, put the glue above the 3rd layer instead of under the 4th layer to make sure you don't add glue on places that shouldn't get glued.

As for the 3 first layers, make sure it's precisely aligned with the others !

Step 11: Main Drawer's Lockers

The main drawer has 2 locking systems related to it.

The first, and most obvious one, avoids it from opening without pressing a button.

The second is actually released when the main drawer is opened. It avoids from closing the secondary drawer before closing the main drawer.

The reason for this is that the main drawer's locking system could get damaged if the main drawer was closed after the secondary drawer.
The secondary drawer blocks the button that opens the main drawer (it's part of the enigmas), if the button is blocked, the drawer cannot be properly closed neither without forcing and potentiallybreaking it. The second lock system is there to avoid that. (i'll add a GIF explaining that better as soon as i can)

Step 12: Gluing Springs

Before enclosing the mechanisms with the last layer and the borders, use some Epoxy Glue to fix the springs to the wood.

Apply small pressure to the spring while it dries. For as long as your epoxy glue requires it.

Step 13: Adding the 5th Layer

Before gluing the 5th layer, think about adding the key locker !

Now, the trickiest part of the assembly, adding the last layer of the lid.

This can be a bit complicated as the main drawer's locking system is pushed up by springs. You'll have to manage to push it down while gluing the top layer.

My solution was to, first apply glue on the top of the fourth layer, grab a pencil, push on the spring lock with it, and slide the 5th layer around the pencil through the hole of the 5th layer. While maintaining pressure on the spring, bring the 5th layer in place and hold it in place with clamps.

Step 14: Cutting Lid Sides

Here are the sides of the lid, ready to be cut and engraved.

Be careful not to loose the front of the drawers that will be disconected from the actual sides.

Once cut, glue them to the sides of the lid.

There's only one way of gluing them properly so if you're carefull you shouldn't mix them up ;)

Step 15: Top Elements and Hint Wheels

Last thing to complete the lid is adding the elements on the top of it.

Below you'll find the laser cutting file, just glue the elements.

The small circles with symboles should be placed on the appropriate sliders according to the index shown in the image above, and in the correct orientation (same as in the image).

Finally, the small circles with a simple dash on their border should be placed inside the drawers at the places that matches their shapes.

After this, the lid should be complete and working !


Step 16: Cutting Bottom of the Box

Cut the bottom parts in a 3mm wood and glue them together.

Best way is to start with the bottom, add 3 external sides and glue them. Glue the 3 corresponding inner sides to them. Then finish by adding the last two sides to complete the box.

Add felt fabric on the inside if you wish to get something cleaner.

Step 17: Adding Hinges

Last but not least, the hinges !

MDF is very fragile and can crack easily if you try to nail it. As we need nails to fix the hinges, it's necessary to first drill hole slightly smaller than the nails before pushing the nail.

I set my hinges a bit strangly because they could avoid opening the box too much if placed this way.

Do as you want but just be careful not to hide the engravings on the side !

Step 18: Adding Some Decoration

At this point it's up to your taste and what you have at home.
I added some corners, nails and borders here and there.

I also added some varnish on the top of the box but that wasn't a so good idea in my opinion...Or i would have done better putting varnish on the other sides as well maybe.

Step 19: Tadaaaam

And your box should be complete !

There are some enhancements that can be done:

  1. The sliders can be quite hard to move.
  2. I broke the locking part of the lower box very quickly by closing the box without first pushing back the inner slider, as you'll see in the above picture i replaced it by a, not so trong, metal part for now.
  3. If closing the locker with the key before pushing back the inner slider it pushes the side out of the box
  4. The secondary drawer doesn't comes out quite enough to be able to catch the small wheels
  5. Closing the lid before pushing the back the main lock system can break the hook on the bottom part
  6. I originally put springs instead of the two manual sliders on the left but there was too much friction and we could brute force the sliders quite easily. But the design was cleaner :/.

This will be for another time :)

Hope you enjoyed !

Step 20: Solution : How to Decipher the Hints

Coming soon, i'm exhausted for now T_T

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