I am going to open my first instructable, with a spoiler. Who wants to read through a whole puzzle box build, only to find out that the actual puzzle is boring. So I am going to show you the steps to opening the box. Then if you are interested in building this pretty box with or without power tools, please read on!
I built this with hand tools for fun and also for a little challenge. It also hopefully illustrates, that you can build without a huge investment in tools. Most of the woods that I used are scrap, odd size pieces I bought from lumber yard discount bins to use as inlays and such. The top is Leopard wood, the sides are Tigerwood, the ends are Ambrosia Maple, the knob and dowel pins are Ipe. (None of these woods are listed on the CITES Appendices. )
Step 1: Lock Number One
The first lock is a friction pin. It can only be pushed out one direction. Push it the wrong way it just gets tighter. (Ipe is perfect for something like this.)
Step 2: Lock Number Two
This one is a little more develish. The pin on the left side of the box looks like the other but it is actually false. The backside of the pin is permanently glued in and cut flush. Then I epoxyed a ceramic magnet directly over the cut off pin.
The front side of the pin can be seen but not pulled out of the box...with your finger. It requires a key.
Step 3: Lock Number Two: the Key
The key is inserted into the pin and then used to remove it from the box. The magnet won't let the pin fall out. But it will allow someone to turn it with thumb friction or spin it with the key without coming out. You actually pull the pin out.
Both pins are removed and the knob (key) is returned to the top of the box.
Step 4: The Last Lock
At this point all of my friends were ready to smash the box. This final lock is actually a really old puzzle box device. Done simply with four nails. All you need is a little centrifugal force, spin the box and the lid will open...ta da.
Yeah it looks easy, but would you figure it out? So far best time I have seen so far is well over an hour.
Step 5: Sketching Out a Rough Plan
I always draw out my plans. I apologize for the roughness of the drawing and the instructables as I made corrections as I went.
Step 6: Hand Built
This is a simple box with small components. Yes a router would make the process quicker, but in this case the small components can be worked quickly and easily with hand planes.
You don't need the most expensive planes to do this, especially something this small. What you need is to make sure they are TUNED and SHARP. (Two things that can be done cheaply even with some wet dry sand paper taped/glued to a piece of glass.) The other trick is to take your time.
Step 7: Join the Gang
I gang cut, gang plane when ever possible. Gang cutting makes sure your pieces are equal and square. (At least to each other...) This same principle works for planning as well. Small pieces are easily taken out of square by a plane, so doubling the width helps with not over cutting.
Remember just plane your end grain first. As you plane the end grain you will most likely experience chip-out, on your side grain. Fix this by planning the side grain last.
Step 8: Dowels and Pins
I drilled out the four holes on each side for the dowels. Rather than hiding the dowels or doing dove tails I went with exposed dowels; this creates a neat look with the pins used for the locks. This also can be another red-hearing for how the box is opened. I used a set of dowel centers to mark where the sides needed to be drilled to accept the dowels. A handy tip is to drill one of the holes, dry fit a dowel in to make sure it is aligned properly. Then use a drill bit or forstner bit to check the alignment of the second mark. This way you know your pieces will definitely fit together.
I used a simple and cheap plug cutter to make the dowels out of the Ipe. Then I drilled the larger holes for the locking pins and installed the false permanent pin and magnet on the inside. Glue up with a good quality wood glue, let dry and using a simple flush cut saw to level the dowels. DO NOT GLUE IN THE BOTTOM YET!
Step 9: Lid and Bottom
I cut a mortise or groove at the top and bottom of the ends to accommodate the box lid and bottom. Cutting the groove for the lid so it will line up flush, whereas the bottom I cut short making the bottom piece protrude slightly. (Explanation Below) The lid I tapered the sides with a plane to match the profile of the ends. I then drilled a whole that matched my machine screw for the knob, all the way through the center of the lid. On the underside of the lid, I drilled partially through with a forstner bit to allow for the machine screw nut.
I then epoxied the nut into the hole I had created in the underside of the lid. This allows a more secure seating for the knob to be constantly screwed in and removed rather than just threading the wood. The bottom I don't want flush to the sides of the box, because I want to facilitate the spinning of the box to enable the nails to unlock. So I began planning and sanding the bottom piece so I had a very gentle curve. I didn't want the box to rock like a boat but I did want to reduce the friction for spinning the box by reducing the area of the bottom.
Step 10: Making the Knob...
Ok for this I broke from my hand built mantra. (Sorry..) You can easily purchase a knob, or use a drill lathe to recreate what I did here. The reason for this indiscretion is that this item was a present for the person who gave me my lathe, and I had to include something made on it in this project. (The benefactor of the Lathe was my Dad, but if it makes you feel any better it is over 60 years old. And I wouldn't trade it for a new one.) So the knob is turned out of Ipe, the bottom is tapped with a hole slightly larger than the machine screw shank to accommodate the epoxy. I sized/cut the head off of my machine screw a little longer than necessary, in the hopes that it makes the puzzle-solver doubt they are going down the right road. Epoxied in the machine screw and the lid is ready for finishing.
Step 11: The Locking Pins
For the simple friction pin, I used my lathe to shape down. This could be done easly by chucking the piece in a drill and using sand paper. (My old method) As you can see the pin is slightly conical. This allows it to only be pushed through the box in one direction.
The second pin was easy to build, while shaping the first pin, I just made it a little longer than necessary and cut off a piece before finishing the ends. This is what shows on the outside of the box, the remaining shaft of the pin is made out of the remainder of the maple from the ends of the box. I did this because Ipe is tough and hard but is prone to cracking and splitting when it gets thin.
I drilled a hole through the Ipe end piece for the machine screw to fit through and reach the machine nut glued into the maple. On the back side of the pin, to make it stick to the magnet (duh, I know) I just drilled a hole and interested a cut off nail head with epoxy. The important thing is that you have a magnet strong enough that the pin can't be shaken out of the box and the pin is too short to be gripped and pulled out of the box without using the key. (knob)
Step 12: Centrifugal Nail Lock (Not a Bad Band Name)
Finally the nail lock. This acutally could be tough to build and line up, but make it easy on yourself. Mark and drill all the pieces at once. The two pieces that will be glued into the box holding the nails and the one piece that is glued to the bottom of the lid is for the nails to slide through. You can even countersink both sides of the middle or lid piece to help the nails slide back into position.
The easiest way to lineup and glue the nail holders is to put the lid in place, flip the box over and work from the bottom. This way you know everything is flush with the lid. One important thing to note is the length of the nails. Depending on what dimension you would like to make the box the nails need to be short enough that when in the locked position, will not hit the pin on the far side. Also, the nails need to be long enough that when the box is spun they will stop before falling out of the piece that holds them in the box. Otherwise you will not be able to reset the lock without doing some type of ship in a bottle building magic. (Or don't glue in the bottom.)
Test it a few times and you should be able to safely glue in the bottom.
Step 13: Finish and Notes
I finished the box with some simple Zinsser spray shellac. I didn't finish the inside as I was debating whether to paint it black. So that after the first pin was removed it wasn't so easy to see the inner workings. I am actually halfway glad I didn't. Once most people get the friction (easy one) pin out the start looking at the nails they seem to forget the other pin and start trying to get in through the open hole.
Thanks everybody. I hope you found this interesting and understandable.