In this simple puzzle box you have to open a tiny drawer by deciphering hints engraved on its top.

Some tools included need to be used to unlock other tools and solve enigmas which makes it a "Sequential Discovery" kind of puzzle.

Designing this puzzle and writing this article required A LOT of time.

I'm sharing it for free but i'm very open to tips.

You can also buy this box or any other of my puzzle boxes from this website:

https://box.durss.ninja

You can also request a kit of this box if you want to build it by yourself. Just specify it when filling the form on the website.

Supplies

x22 - 6x2mm (0.23" x 0.07") magnets (amazon)

x1 - Tiny luggage padlock (amazon)

x1 - Push pin fridge magnet (amazon)

x1 - 6mm (1/4") chicago screw (amazon)

x1 - 300+x150+x3mm (11.8+" x 5.9+" x 1/8") birch plywood sheet (amazon)

x1 - Masking paper tape roll (amazon)

x1 - Wood varnish (amazon)

x1 - Wood glue (amazon)

x1 - Sandpaper 80-120grit (amazon)

x1 - Threadlocker (amazon)

x1 - 2.5mmØ wooden skewer (amazon)

x1 - candle or candle wax

x1 - Wood carving knife or a cutter

x1 - Caliper (amazon)

Step 1: Tape the Wood Sheet

Taping the wood sheet will avoid leaving burn marks on the wood.

Laser cutters usually make burning marks due to the heat and ventilation next to the laser head which doesn't looks good.

Adding tape makes it so the burning marks are only left on the tape, leaving the wood under it much cleaner.

Step 2: Laser Cut

Use the attached SVG to cut the plywood sheet.

Red lines are cut through paths.

Gray lines are scoring path (light cut that must not cut through the wood but just its surface)

The image above shows the params i'm using and estimated cutting time on my Glowforge basic.

IMPORTANT: The SVG has been exported from illustrator. It's not the most SVG compliant software. Before lasercutting it make sure the magnets' holes are ~5.8mm. If it's not the case, scale the design accordingly.

For example if the holes are 4mm on your software, scale the design by a factor of 5.8/4 => 1.45

lasercut.svg
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Step 3: Peel Off Masking Tape

Remove the masking tape from all the cut wood parts

Step 4: Sanding Moving Parts

Many parts will have to slide between the top and bottom parts of the puzzle.

For them to be able to slide you will have to sand them so they are at least 0.2mm thinner.

Use the 80grit sand paper to scratch as much of the parts then soften it with higher grit if you have any.

Measure with a caliper, if you have one, the thickness before sanding and make sure the part is as evenly

thinner as possible.

The parts that need to be thinner are all the ones on the picture above.

Be careful not to sand the sides that have lines on them, these are important hints to solve the box !

Step 5: Wax Moving Parts

Sanding the parts made sure that they won't be clamped between the top and bottom parts but it probably won't be enough to make them slide smoothly. There will still be lots of friction.

To reduce that friction, we will use candle wax.

Simply rub a candle on the bottom side of the pieces as well as their sides.

Step 6: Glueing Middle Parts

Many pieces have to be glued as precisely as possible on the back piece.

Use the template lines to help you place the pieces correctly.

Once all the pieces are glued, place the moving parts as in the 2nd picture and make sure they all slide properly

Step 7: Critical Part 1

There are some parts that must slide really well or the puzzle reset won't work properly.

The first one is the top right part in red on the picture above.

To make sure it slides properly and the mechanism won't stay locked, push it down against the little rod (in blue).

Apply a constant pressure downward on the red part and pull down the green part.

The red part should be free to go down on place of the blue part.

If not then try to very slightly shorten the blue rod.

See the attached video to better understand the manipulation if necessary.

Sequential Discovery Puzzle Box - Step #7
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Step 8: Critical Part 2

Now we need to do the same test for the top left part.

This time put the red part down, make sure the blue part goes inside its groove, and apply constant pressure upward on red part while pulling down the green part.

The red part should be able to go up.

If it does not, try to slightly shorten the blue rod.

Sequential Discovery Puzzle Box - Step #8
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Step 9: Adding Magnets

Here comes the tricky part!

You have to place all the magnets the proper way.

The picture above shows you how which way you need to place them.

But you have to make sure the red is attracted to the push pin magnet!

The idea is that the push pin will need to attract the magnet from the outside top of the box.

Step 10: Make Sure It Works

Before glueing the top of the box we need to make sure things slide properly one last time.

Push the key holder on the left very gently, it should automatically close at some point
The top right part should be pushed down
The top left part should be pushed up
When everything in "open" state (top right parts on the top, top left part the bottom), pulling down the middle part should release the top left/right parts.

If any of these do not work, you might have to sand the sides of the moving parts to reduce the friction against the fixed parts.

Step 11: Varnish the Top Part

I'm no varnish expert so there might be a better way of doing this.

But, what I do is I put varnish on a tissue then I rub the wood surface with it and repeat the process until all parts are covered.

Step 12: Add the Padlock System

Glue the fixed part (image 1) on top.

Put threadlocker on the chicago screw (image 2) and assemble it on the top part (image 3)

Step 13: Digging a Hole

The chicago screw of the top part has some thickness that would induce a gap if we tried to glue the top part.

To avoid that we need to dig the red part of the picture for ~1,5mm.

You should have a laser cut line indicating the area to dig.

If you have a wood carving knife it's the best, but you can also do it with a cutter as well. Just be careful with your fingers !

Step 14: Adding Cursors

10 cursors can be moved from the outside of the box.

There are only 2 kinds of cursors as shown on the first image.

The two cursors named "1" must be inserted on the parts as shown in the second image.

The cursors named "2" must be set inside the grooves on the right of the board and in the proper orientation.

They all have a short lead and a long lead and must be placed as shown on the 3rd and 4th images

Step 15: Glue Last Layer

Final step, gluing the top part above the others.

Put glue on all the red parts but be VERY careful not to put too much glue.

We will clamp the board after to make sure it sticks properly and this will spread the glue a lot. If you put too much glue near the moving parts of the mechanism, the glue may flow into them and glue them which would completely break the puzzle.

Once glue is applied, put the top part above it and clamp it.

Aligning might be quite tricky due to all the cursors that must fit on their holes. You may want to use a toothpick to wiggle the cursors one by one until the top part fits.

Last thing, cut a 9mm long chunk of the skewer and insert it inside the tiny hole on left of the board. This will be the rotation axis of the key's drawer.

Tip : Don't try to close the final drawer before gluing the top board, magnets will drive you crazy, just leave it opened, you'll close it once glue has dried