Introduction: Segmented Wooden Cryptex
Since the release of Dan Brown’s The DaVinci Code, the Cryptex has become an iconic puzzle. While this one won’t destroy itself, it will certainly keep its share of secrets. This project is mainly designed to be an exercise in segmented woodturning.
Upon initially finding the design for a wooden Cryptex, I wanted to build one on a lathe instead of a drill press. I knew it’d be difficult, time consuming, and require a fair amount of patience. With that said, this isn’t the project to rush through to make a deadline. Take your time and go slowly. How slow? Each ring contains 26 staves plus 12 border segments. That’s upwards of 300 separate pieces on a seven-ring design. I’d also recommend making spare rings…
There aren’t too many critical tools to have access to, but you will need a table saw, miter saw, sander, Pyrography iron, lathe with a jawed chuck and more than a few clamps. It’s also helpful to have a digital angle gauge.
Step 1: Cutting Ring Staves
The original designs used a circle cutter on a drill press to make the rings and a dowel for the center chamber. I didn’t like marking off 26 notches around the outside and thought there’d be a way to make them with a lathe. I settled on a cylinder with 26 staves so the joints would separate the letters. To do this, each one will need to be ripped at 360/26/2 = 6.92 degrees.
Start by deciding how big your want the rings to be. The outside width of the staves will dictate your circumference. Ex: 1” on the outside means a 26” circumference and an 8.25” diameter. Size this to fit on your lathe chuck or your desired payload.
Begin by cutting a few wider boards at 12”, bevel your table saw blade at 6.92 degrees and rip them down to create 26 staves. Glue them up in pairs, let dry, then 4’s and 8’s. When you’re down to 3-4 sections, assemble the cylinder using a band clamp. If you want something really awesome, add bits of veneer between each piece. Use lighter wood so the burned letters have enough contrast. I used mahogany for mine but I’d probably go with something stronger.
Once you have your cylinder, clean the glue from the outside and cut 1” wide rings on a miter saw, trimming off the last bit with a hand saw if needed. Use a disc or drum sander to clean up both sides of each ring. Keep at least one ring at 2” or wider for the end.
To add definition between each ring, I added a ¼” band of walnut. These were cut individually with 12 pieces and then glued down to each ring. These walnut blocks were cut on the table saw at a 15 deg bevel similar to the staves. The walnut also served to strengthen each assembly. Instead of making more rings, cut them down to ¼” in thickness and glue them to each ring. Use a spindle sander to round down the assembly.
-Table saw setup 2x
-Completed ring staves
-Gluing up the ring assembly
-Cleaning glued assembly
-Gluing down walnut walnut bands
-Sanding rings flush
Step 2: Turning the Rings
Lightly clamp each ring to your lathe chuck and use a skew to clean up the inside of each ring and a tool of choice to clean up the outsides. Once they are evened up, carve a 5/16” tenon down on the outside about ½ way through the blank. On mine, I started with a 5” diameter and went down to 4 7/16” on the outside
Flipping the blank over, use a skew to trim a matching recess on the inside of the walnut side. This one will be 3/8” deep to make room for the locking pegs later. Using a caliper, standardize the outside diameter, drop the walnut band down by ~1/8” and lightly round over the outside edge for extra definition. Sand all surfaces. Test-fit all of the rings and adjust as necessary. I found it helpful to number each ring and then cut each one to fit its neighbor.
Burn your alphabet into the rings using a standard burning pen and a knife to extenuate the divisions between the letters. Choose your password and use a detail saw to cut away the inner tenons behind the letters of choice. Thinner spaces require more precision in dialing the password.
For the right end, we need a ring with two tenons to connect to the rest of the stack and fit into the side. Take your leftover ring material and turn it down with two tenons, one to fit the last ring and the other to fit the right side. Carve out one inner tenon to allow the chamber to pass later and mark the outside with your burner.
-Getting the rings to round
-Rings mounted on lathe
-Walnut center chamber assembly
Step 3: Building the Sides
Draw out a design for each side. I normally use MS Publisher.
Simple: square with 4 connecting dowels. Intermediate: complex shape with 3 mortised posts. Advanced: Segmented, multi-layered and turned to contrast the rest. Make your choice. J Although I’m usually up for a challenge, it’s cold and getting late.
Cut out each end, carefully mark the centers, and then sand and route the edges. On both sides, use a hole saw in a drill press to cut recesses to fit the tenons on the rings. I used a Glaser screw to cut each one instead. Add a smaller through-hole to the right side for the center chamber to pass.
Test fit all components but don’t glue it together yet.
-Planed supports before trimming down tenons
-Completed left side
Step 4: The Locking Pins
The chamber is held in place by a series of protruding finish nails that will ride in the recesses between the inner rings. Sit the chamber in the left side and add rings one at a time, marking the location of each recess. Pre-drill the holes along a single line, add the nails, glue in place and use a rotary tool to smooth the heads.
-Turned chamber with nails glued in place
Step 5: The Caps and Finishing
Almost done now! Cut a block to use to close the chamber off. Carve a tenon into the inner surface that will fit the remainder of the chamber’s open end. Add a mark to align the chamber with the rings and use your burner to add a clue in the end. Or don’t…
Finish however you'd like. I used danish oil since I didn't want the assembly seizing up. It also gave an awesome color to the wood (Mahogany, Walnut and Sapele).
There, now wasn't that fun? Now go drop one on a friend's desk and watch the fun begin.
-Detail on end caps
-In the finishing room
-Complete Cryptex + the 5 year old test article
Step 6: What Can Go Wrong?
Learning experience here.
This project had a number of first’s for me, plus I rushed along to finish the project in time. Don’t make my mistakes; here are some lesson’s learned…
-Precisely measure your staves for the rings. Any bias will be multiplied 52x by the end. i.e. being off by 1/10 of a degree will make the ring off by an entire letter. Once you have the blocks of 4-8, use a joiner or disc sander to clean up any biases.
-Give your glue enough time to dry. I’m in a cold climate and didn’t have the time to let all of my joints set. I ended up breaking about ¼ of the joints in the rings due to substandard gluing.
-Make spares. If nothing else, you have parts to practice on.
-Use a contracting chuck to hold the rings. If you’re limited on equipment, size the puzzle to your abilities.
-Measure, write down, and standardize all of the rings. I free-handed way too much of this one and now want to redeem myself.
-Make the center chamber a little large and allow yourself room to turn it down to precisely fit the rings and ends.
-Previously completed Cryptex (USAF edition)