- A Box in a Box- the start
- Facade You Are- the outer box
- The Top and Sides are Fake- more outer box pieces
- The Finish is Finished- sanding, staining and varnishing
- A Faux Hasp and Secret Latch
- The Release Mechanism- the sides slide
- Hiding Some Clues and Adding Handles
- I Can Stop Myself-adding stops to the sides
- Hiding the Bottom Slot
- Shhh…This Drawer is a Secret
- Hiding the Keys
- Now to Stop the Top
- Some Pads for the Bottom
For my latest project I had this idea to make a puzzle box. A puzzle box is a box that cannot be opened without figuring out hidden locking mechanisms. I first saw a puzzle box in 7th or 8th grade when a schoolmate of mine brought one to school. A little later when we had the opportunity to make an independent project in wood shop, I made one there. It turned out all right, or at least as well as a 13 year old with no plans could create. Unfortunately that box is no longer around, so I can’t show you what it looked like.
Let Us Begin
My idea is to make my puzzle box look like an ordinary decorative box that opens with an ordinary flip top lid. What follows is the complete process of making the box from beginning to end. Unlike previous projects, I completed this one before posting the progress. I am hoping this will allow me to shorten the blog a bit while still giving enough information to anyone interested in creating a similar box.
This puzzle box is quite a bit more complicated than the one I made in 7/8th grade, but the overall layout of sliding sides and top are the same. So is the presence of a secret drawer under a false bottom. To start this blog I have some pictures of the completed project as well as a short video showing the puzzle solution, i.e. opening the box. The first two images are of the puzzle box closed and opened. After that I added a video showing the secrets to opening the box.
The Box in a Box
The design I came up with is a small box that would have a facade added around it that would allow for the sliding pieces to be layered into place. So this box will actually be inside the outer box.
To make the inner box I used some quarter inch poplar cut into the six sides for the box shape.
After cutting the wood to the proper lengths, I glued the two long sides (front and back) to the bottom and false bottom pieces seen in these pictures. The top was not glued, but acted as a spacer during clamping. The short sides were not glued either but acted to keep everything square during gluing. The top and sides will need to slide freely in the completed box.
Nex,t using two pieces of poplar, I added a layer that overlaps the inner top and that glued in place on the left. I made this piece from two parts because I didn’t have a wide enough piece of quarter inch poplar to do it with one. This whole top piece slides back and forth when the inner top is slid inside the front and back pieces. The top layer acts as a guide holding the top in place, as can be seen in the right side picture. The top layer will slide inside a groove that will eventually be inside the facade. You can also see a better view of the false bottom in the picture at the right. This is where I’ll put the secret drawer in the finished piece.
Facade You Are
The facade pieces for the left and right side I made from two pieces of quarter inch oak . These were glued together to make a false seam that will make the sides look like the top piece is the lid.
The front and back facade pieces were made the same way, though these were made from 3/4 inch oak. In the picture on the right I have set in place the four facade sides around the inner box in what will be the final locations.
Another view of the facade pieces set in place is on the right. I will glue the small wood strips in the other two pictures to the edges of the front and back. You will see that when the inner box is glued to the front and back facades, a slot will be created in the top, front and back sides. These slots are where the top, left and right sides will slide when opening the box.
The Slots take Shape
The gluing of the wood strips is shown here. The bottom left is the back piece. The notch at the top left allows the left side to slide up to reveal the hidden drawer. The notch on the top right allows the top to slide to the left. The right side slides down, so it doesn’t need a notch. The front side pictured on the above right is just the mirror image of the back.
In this set of images you can see the back facade being glued to the inner box. In the center top image the slots created in this process are most visible. On the lower pictures I have slid the top and sides into these slots to test the progress so far.
I glued the front facade in the same way as the back. In this set of pictures I’m showing this process. The box is really starting to take shape now. In these pictures you can see clearer views of the slots that the top and sides will slide through.
This is Now a Box
Doing another test, I slid the inner top and sides into the slots of the main box. The box is now beginning to function as it will when completed.
When I insert the top and sides, there are quarter inch gaps that you can see here between the inner sides and where the facades will need to be.
I used some quarter inch slabs that act as spacers to fill these gaps.
Top and Sides are Fake
These are some additional views of the spacers that I glued to the top and sides. On the right, I marked one of the side pieces for pre-drilling. The facades for the top and sides will be glued and screwed in place. This will provide the sides with extra strength as these are moving parts.
The left side was glued and screwed in place. In the bottom picture the opening for the hidden drawer is revealed after sliding the left side up.
The top slides over the left inner side holding it in place when closed.
In the top left picture you can see where I glued a back stop for the drawer opening into place. I glued and screwed the right side facade in the same way as the left. You can see here that when the right side is slid into place it prevents the lid from sliding so the box cannot be opened when the right side is up.
Topping it Off
As with the sides, I glued and screwed a quarter inch facade to the spacer of the top.
For the bottom I cut a wood plate from quarter inch oak. I screwed this plate to the 3/4 inch front and back facades. I didn’t glue this piece. By just holding this with screws, it will be easy to remove if something goes wrong with the inner latch mechanism. By taking off the bottom, the left side can be slid down and out without releasing the right side. In the bottom left image you will also notice the gap on the bottom of the box. There you can see the right side slot. The right side slides down through this slot, so the bottom cannot extend to cover this.
To keep the bottom flush, I cut a small quarter inch bottom strip that I glued to the right side.
Now the Box is Complete….so far
This is a series showing the right side with the bottom plate piece attached and then slid into its slot in the box.
Finally, all of the facade has been completed as you can see in these images. The base part of the box is completed and ready for the addition of the hardware and locking mechanisms.
These pictures show the puzzle box in action with the side slid down, the top slid to the side and the left side slid up revealing the drawer slot. When closed, the top holds the left side closed and the right holds the top closed. The bottom picture shows the back side of the box so right and left are reversed there.
The Finish is Finished
Using a belt sander, I smoothed all the surfaces and made sure all sides flush and ready for staining. I did a lot of sanding in the grooves to everything get every to slide nice. I used paraffin wax in all the grooves as well to keep them sliding well. Hopefully when the humidity goes up it will prevent them from swelling and locking the box shut in the summer.
I used a red oak stain.
The final finish is a gloss polyurethane varnish.
A Faux Hasp and Secret Latch
These are the hasp, hinges and lock that I will use to complete the illusion of an ordinary locked box with a flip lid.
My idea is to make a release mechanism disguised as the loop for the hasp. In order to release the right sides to slide down, you will first have to remove the lock and flip up the hasp. Then rotate the loop to the left. Only then will the right side slide down. The first piece I made for this was the locking shaft. It was made from a 1/2 brass rod turned to the shape in these pictures on the lathe.
I drilled a hole into the front of the box and then counter sunk it so the locking shaft could be inserted.
The locking shaft is then faced off so that it sits flush with the wood surface. This allows the hasp to lie flat over the top.
Adding a Loop
In the left image you can see the locking shaft extends into the box. This end has been drilled and tapped to accept a #8-32 screw, which will act as a backup to prevent the rod from coming loose if other mechanism parts were to fail when the box is closed. The thin brass rod seen in the center image is used to make the loop for the hasp. The mechanism will work by turning the locking shaft to the right. This will pull a pin from inside the right sliding side. The hasp/loop will prevent you from turning turning the shaft when the hasp is down.
The brass loop was soldered into the locking shaft. This loop also works as a small knob for turning the shaft.
An Inside Ring is Added
Cutting a flat spot onto the locking shaft allows a set screw to seat securely against the locking shaft. I cut inside diameter of the ring to the diameter of the locking shaft. Two holes were threaded and tapped into the ring. One is for a set screw, the other will hold part of the lever action for the release mechanism.
This is the basic design of the right side release mechanism I sketched it out on paper using some brass pieces to work out the design. The image on the right is the almost completed lever/yoke pieces. I used two pieces of quarter inch brass stock to make yokes. One attaches to the locking pin the other to the ring. The picture on the right also shows the 1/8th inch rod that will be soldered into the yoke. This locking pin will insert into the right side slider preventing it from moving when shaft is rotated to the right. The brass piece in between the yokes serves as a connecting rod. When the locking shaft is turned left it pulls the connecting rod and slides the release pin out of the right side. The right wooden side can then be slid down starting the box opening process.
The Release Mechanism
These pictures show the two yokes being fabricated. One has a hole that is drilled into the end for the release pin to be soldered into. The other has a perpendicular hole drilled so it can be attached to the release ring. Both are drilled through the yoke ends so that pins can hold them to the connecting rod.
Using a small block of wood as a release pin guide, I drilled and glued into place against the right front of the inside of the box. This will help guide the release pin as it slides in and out of the right side.
Here I assembled the release mechanism to see how everything lined up. This test used a temporary connecting rod.
After cutting the release pin to length and rounding one end I marked and drilled the right side where the pin will slide into. .
The Locking Mechanism
The release pin could now be soldered to the yoke.
With the release rod and yoke inserted into the right box side and the other yoke screwed to the ring, I tested for the best length for the connecting rod.
The Real Connecting Rod
Once the correct length was determined I then made the final one from quarter inch brass square stock.
Brass wire was cut to length and soldered into place holding the two yokes, connecting rod and release pin all together.
This is the whole release mechanism assembled outside of the box.
Putting it Together
When installed into the puzzle box, you can see, as the release shaft is turned, the release pin is pulled from the right side of the box allowing it to slide down.
Hardware Hasp and Hinge
These images show the box put back together so far. The hasp has been screwed into place and the sides and top slid into place.
On the back side I attached faux hinges to complete the illusion that the box has a flip top.
Hiding Some Clues and Adding Handles
The right sliding side has a separate bottom from the rest of the box. There is a gap or slot visible seen here in the left picture from the back of the box. Left as is it would serve as a clue that there is something not quite normal about this box. To hide this, thin brass quarter inch strips were cut to be mounted along the bottom edges of the front and back of the box.
The brass strips, once mounted, hide the small gap/slot on the bottom of the box. I used the front brass strip to add my initials and year “JTS 22”.
And Now the Handles
The sliding sides fit very snuggly. To help slide them up and down, I decided to add decorative handles to each side of the box. I made them from quarter inch brass square stock. In these pictures I am cutting them to the correct length.
The handle pieces were then drilled and tapped for #6-32 screws. The holes line up with the screw holes in each side of the box.
To give the handles an added feature, I used a 3/8ths inch end mill to cut a notch into both handles.
I then used the rotary table on the mill to cut round ends onto each handle.
Attaching the Handles
Holes were drilled all the way through both sides and the inside holes counter sunk so I could attach the handles to the box.
I Can Stop Myself
With the sides complete I wanted to add some stops that would only allow the sides to slide far enough to open the box and access the secret drawer. If I didn’t do this the sides could be completely removed from the box. This means they could get separated or lost over time.
For the right side this was pretty easy. I measured how far down the side needed to go for the top to slide past it. I then added two small wood screws so they would hit the false bottom when the right side was slid down.
Left Side Stops
The left side was a bit more difficult. I measured how high the side needed to be slid up to reveal the secret drawer compartment. Then added screws as with the right side.
Then I needed to add a second set of screws to the inside front and back surfaces. The side screws impinge on these surface screws when the side is slid up preventing it from sliding all the way off. When slid fully up, it opens just far enough to expose the drawer opening.
Hiding the Bottom Slot
When added, the brass strips hid the slots on the bottom of the front and back, but a slot remains visible on the under side of the box. It is just visible on the right side of this image. To hide this, I decided to add some wood slats to the bottom of both sides to act as “feet”.
The feet were cut from one inch by quarter inch oak strips. They are pre-drilled and the bottom marked for screwing these on.
The holes were counter sunk and then the feet were painted black. After the paint dried, I screwed the feet into place. Now the bottom slot is hidden under the right foot when the box is closed.
Shhh… This Drawer is a Secret
It was now time to make the secret drawer.
Brass sheet metal was used for the bottom of the drawer. I cut the side pieces to length from quarter inch by half inch poplar strips.
Using right angle clamps I glued the side pieces to the front and back. After the glue dried, these two drawer pieces were glued together into a frame.
The drawer bottom was cut to shape and then pre-drilled for the brass nails that will hold it to the sides.
Drawer Needs a Knob
Using a half inch piece of brass stock I shaped it into a drawer knob on the lathe.
The front of the drawer was then drilled in the center so the knob could be held in place with a #6-32 screw.
To attach the bottom to the drawer I used small brass nails . In the center and right pictures, you can see the drawer slid into the puzzle box.
Hiding the Keys
Though the lock does not keep the puzzle box closed in the traditional way, it still needs to be removed in order to release the right side and get the box to open. I didn’t want to have the keys separate from the box, so I decided to hide the keys inside a handle on the top of the puzzle box.
To make the handle I used (2) quarter inch square pieces and (1) half inch flat piece of brass. The keys will be hidden under the half inch piece. The two quarter inch pieces will be soldered together to make it match the width of the cover piece. I didn’t have a half inch by quarter piece handy so I needed to make one.
As the rotary table was already set up, I used it to round the ends of these pieces to the right length.
In these pictures I have soldered the (2) quarter inch pieces together. Everything was filed and sanded smooth as well.
The ends of the lower piece were milled in the shape of the key at a depth that was the keys thickness.
With the milled ends and the cover in place you can see how the keys can be slid into the handle. In the upper right image, two holes have been drilled into the handle so it can be fastened to the puzzle box.
These are some more views of the completed parts for the handle.
I didn’t want this piece to mount directly to the box, so I made two brass disks with holes in the center to act as offsets.
Next I drilled two holes into the top of the puzzle box and counter sunk them. Screws through these will hold the handle to the puzzle box.
Keeping the Keys on Place
The keys slid easily in and out of the slots in the handle. To have them held in place a bit more securely I came up with the following. I drilled quarter inch holes in the bottom handle piece at the locations of the ends of the keys. Through these plugs made from quarter inch brass rod can be inserted. These plugs will be spring loaded to hold the keys in place while being loose enough to allow ease of key extraction.
Using an old piece of clock spring I cut it to the same length as the quarter inch plug holes. I then drilled two holes in it with the same diameter and distance as those for holding the handle to the box. In the last picture you can see the handle assembled for testing. The spring is clamped between the offsets and the bottom handle piece. The plugs are inside the handle in the holes drilled for them. The spring pushes the plugs against the keys holding them in place. The tension is enough to hold the keys, but they can still be removed with your fingers.
The pieces were disassembled and then put back together with the screws holding the assembly to the puzzle box. The wood screws that run along the front and sides of the puzzle box were re-inserted and screwed into place.
Now to Stop the Top
We’re getting very close to the end with just a couple of things to do. The next step is making a stop that will prevent the top piece from being completely removed.
I will use one of the wood screw holes in the top to do this. By drilling it all the way through a screw can extend through the top and hold a brass rod in place that will act as a stop. Originally I was going to have two stops so the picture on the top left has two screws removed. I realized that a stop through the front hole would hit the release mechanism on the inside front of the box, so I settled on one stop at the back of the lid.
The stop was cut from quarter inch brass rod. I cut it to length and one end was rounded with a file. The other end was drilled and tapped for a #6-32 screw.
T give the stop more strength I counter sunk the hole about a half into the top with a 1/4 inch drill. This allows the brass rod to be inserted to depth giving it more support. Next, the screw was inserted into the hole in the top and the rod fastened in place. Finally in the bottom picture, you can see the stop in action with the lid slid all the way open. With the stop in place the top cannot be slid further when the stop hits the right side piece.
Some Pads for the Bottom
Finally, some adhesive felt pads were stuck to the bottom of the feet.
And there we are. The box is complete. I hope you have enjoyed the process and thanks for looking.