Mechanical Puzzle Box | Trick Box or a Secret Box




Introduction: Mechanical Puzzle Box | Trick Box or a Secret Box

About: Handmade crafts and products that I make using recycled or waste, cheap and easy to available materials. Also custom products are made using a mix of materials.

This is a homemade Puzzle box (also called a secret box or trick box)made for storing secret items.It is a box that can be opened only by solving a puzzle, as it need a combination or a specific way to unlock.

Some puzzle boxes require only a simple move and others a series of discoveries. But, our puzzle box requires a two-step process to unlock.

This is a wooden box (made with mdf and ply) with a lock mechanism (made with pvc and metal). This is just to showcase the idea, but for more safety it can be entirely made with metal.


Below are the Tools and Materials that I used for making this simple Trick Box.


  • Hacksaw
  • File Set
  • Cutter
  • Plier ( or nipper )
  • Clamps
  • Ruler
  • Pencil
  • Compass
  • Sandpaper
  • Drill Machine


  • Mdf Board
  • PVC Sheet
  • Plastic Sheet ( strips )
  • Plywood ( 2mm )
  • Plastic Tube
  • Wood Glue
  • Super Glue


  • Metal Rod ( or nail 3mm )
  • Nut & Bolt ( 6mm )
  • Neodymium Magnet ( 4mm )
  • Coating Agent ( wood varnish )
  • Spray Paint ( silver )
  • Color Pen ( black, red & blue )

Step 1: Design the Box

Here I made the puzzle box mainly with 4mm mdf board and 2mm plywood. The dimension of the box is going to be 85x135x85 (lxbxh)mm.

Though there will be gaps for placing the lids, joining and other settlements, the size of our wood pieces will also vary.

Thus I marked and cut the mdf and ply pieces according to the sizes I need.

Step 2: Prepare Box Sides

Next, I used normal wood glue (fevicol SH) and joined both mdf and ply pieces together to form the box sides.

After drying they looks like above.

Step 3: Add Cover Holder

Next, I cut 2 identical mdf pieces of same length of the box and glued them to the top of our box sides.

This is mainly to hold the top lid or top cover to slide through it.

Step 4: Join the Box Parts

Now, I glued all the four sides of the boxes together with wood glue and kept for drying.

Step 5: Making Lock Chamber

Here, I cut two small pieces of mdf to make the lock chamber where our locking mechanism will be installed.

Thus I again glued the 3 pieces inside one side of the box and kept for drying.

Step 6: Adding Bottom Cover

Then, I glued the bottom piece of our box and thus our box is partially completed now.

Step 7: Making Lock Mechanism - I

Now is the time for making the lock mechanism. Here I used PVC sheet and a metal rod for making the lock.

I cut out 4 circles and joined two of them together to make it a bit thicker. Then I cut on one side of the circle and made couple of holes in it.

Also you can add some counter weight in the bottom part so that when it is mounted, on rotating it always stay at same position.

Step 8: Making Lock Mechanism - II

Basically there are two circles that will be mounted on a metal rod so that it can rotate freely. The circles are partially cut on one side so that our top lid can pass over it. The holes in the circle plates makes it stable upon rotating at any angle if hold horizontally.

Step 9: Installing Lock Mechanism in the Box

Now is the time for installing the lock mechanism to the lock chamber in the box. careffully insert the metal rod through the hole and place both the rings along with spacers( made with pen refile).

Thus you can see that, it is placed at a position where a small part of the lock is coming out above the box line. It will be get stucked in the top cover plate and wont let it get open.

Step 10: Making Lock Stucker

Here, I cut out a rectangular part from the top cover plate, where the lock mechanism will get stucked and wont let it move. It can move it distance of 1 to 2 mm depending upon the lock and cutting gap, but wont get opened.

Step 11: Adding Stopper

Next, I added a Nut and bolt on the other end of the top cover. It will be on the inner side and will be installed once the top cover is inserted at a certain distance from the lock chamber.

The purpose of it is to hold the plate and wont let it come out upon opening the box.

Step 12: Adding Magnets

Next I added a small magnet on the cover plate and in the box also to prevent it from sliding automatically.

Step 13: Attaching Design Pattern to Top Cover

Here, I added some design patterns in the top cover plate. This is a bulb like a design made with plastic strips and pvc.

I only added the lining of the bulb pattern.

Step 14: Coating & Coloring

Next, I applied wood Varnish on the box and Silver color to the top cover plate.

Step 15: Coloring the Bulb

Then, I applied black color to all along the bulb lines and bulb threads.

Step 16: Adding Logo

Next, I also made a small logo of my channel (technocraft Studio) and placed in the middle of the bulb and thus colored them.

Step 17: Covering the Lock Pin

Lastly, I made small lid out of wood and covered the lock pin. It is also to confuse people to think it as a switch or a way to open the box.

Step 18: Inserting Top Cover Plate

Now, insert the top cover plate along the lock side and screw the stopper. Thus its now locked and can only be opened via the specific method.

Step 19: How to Open the Trick Box

This a a two step method to open this puzzle box. I think some of you has already decoded it, but if not here is the simple way to open it.

  • The box should be hold straight or horizontal.
  • Now slowly rotate the box on one side and push the top lid to pass the 1st lock circle.
  • Then rotate the box on the opposite side and push the top lid again to pass the 2nd lock circle.

Basically what is happening here, when the box is tilting, at a certain angle the top cover plate and the lock circle will come to a parallel straight line and thus it will easily come out from the rectangle part of the top lid where it was stucked before.

With this simple trick applied on both the sides it will easily get unlocked.

Step 20: Finished Product

Here is our final finished product the Puzzle box or Trick box or a Secret box. Now you can store anything valuable or confidential items in it and nobody can open it without knowing the trick.

Hence it is safe for placing anywhere you think somebody may see it without your permission.

Here, you'll get a 75x105mm of box space to store your items.


Hope you have liked this instructable.

Please comment your views below.

And SUBSCRIBE to our YouTube channel "technocraft STUDIO" for more amazing crafts and products like this.



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    3 months ago

    Clever!! I really like the solution... thinking it would be a good project for my grade 8 wood/metal class!


    Reply 3 months ago

    Yes definitely it would be a nice project, don't forget to share with us.