This project has been made on a laser cutter that I used at FabLab Innovation (http://www.fablabinnovation.dk/)

Ever since seeing the movie - the Da Vinci Code - I have been fascinated with the cryptex, a small scale combination vault, that can only be unlocked by entering the right word on the scroll, allowing the user to pull out a tube which contains some sort of secret.

I decided to construct my own cryptex using laser cut parts, by that I mean only laser cut parts. In this project I developed 3 versions, an initial prototype to see if I could construct the basic mechanics in the cryptex, a second version that had a more aesthetically pleasing design, and the third and final version that had some improvements, that I came up with on my own. The cryptex has a total of 343 parts that are glued together. In this instructable I will describe the process and thoughts behind the different features in the cryptex and how I build it. I will also include the files for building one yourself.

If you like this instructable, please consider voting for it in the Full Spectrum Laser contest by clicking vote in the upper right corner of this instructable, I would really appreciate it. Thank you in advance.

Step 1: The Final Version

Before going through the process of creating this cryptex. I will show the final version.

The final version has the ability to lock in secrets using 10 discs with 26 letters on each disc, that is a total of 26^10 different possibilities or 141167095653376 different possibilities, of course, in practice this is not true, because a cryptex will normally contain a keyword that makes sense, eg. in the Da Vinci Code the keyword is "apple", so a lot of possibilities can be ruled out, eg. words like "ehuakebnps" which is just a sequence of random letters, this can of course also be the keyword, but it is highly unlikely considering that a cryptex is normally unlocked through some kind of riddle.

In the first two versions, I had some issues with positioning the letters 100% correctly, so it could be difficult to unlock the cryptex, so in the final version I added a "click" function, where the disc would be turned 1/26 of a turn and click into position, it could also only be turned clockwise (when looking from the right hand side), this made it far easier to position the letters, and also gave a nice rattle sound similar to the one that can be found in a ratchet, while the mechanism I used in this cryptex, is almost identical to the mechanism found in a ratchet. I also raised the disc with the letters, making turning the disc a fair bit easier, since I expected some resistance from the clicking mechanism.

I can of course not claim the mechanical design in the cryptex as my own idea, since it is exactly how a standard combination bicycle lock works, but the idea of inserting a spring loaded gear to add the clicking effect, I believe is original. It might be that somebody else got the same idea, but I came to this idea independently.

The whole cryptex is made entirely out of 3 mm. MDF, and uses a total of 343 parts, though 260 of those parts where the individual letters, because each letter had to be inserted so the cryptex could be made to open up with a chosen keyword. Assembling one takes up to a few hours. The whole thing is assembled using only PVA glue, and afterwards I gave it some WD40 to make it turn smoothly, though in hindsight using grease would have been better since MDF has a tendency to suck up liquid and expand (though I have had no issues with that so far), and not everybody likes the smell of WD40, I do not mind it though.

Step 2: Basic Mechanics of a Cryptex

A cryptex might seem like an intriquate machine, and in some ways it is, but most of it is the same mechanism repeating itself in a row. Inside the cryptex, there is a long recess that is made out of a series of notches, every other notch (the discs without the letters) are locked into place, the notches on the discs with the letters can rotate though. The tube that sits in the cryptex has some keys or teeth. These keys will sit in the notches that are locked into place, and to pull the tube out, the notches must align to make one long recess where the keys can slide through. If it is a bit confusing the video will explain it a bit better. So as you can see the cryptex is actually fairly simple. Since the end pieces in the cryptex, also are locked into position the can be used to keep the whole thing together. The bars on the outside of the cryptex are the ones that keep the whole construction together, I later moved them to the inside of the cryptex to make it look nicer and so they could not be removed by force and then allow the cryptex to be opened without the keyword.

Step 3: Clicking Mechanism

As I wrote in the beginning of the instructables I had some problems with having to very precisely align the letters to open the cryptex and that bothered me, so I decided that I needed some kind of clicking mechanism so the letters would align themselves. I did that by adding a inward facing gear between the static and dynamic rings(the rings that can not turn and the ones that can, ie. the rings with and without the lettes) and then I also had a ring with a "spring" that would be able to bend down when the gear is turned in one direction but will lock the gear when turned in another direction, this gives it the clicking effect and also makes it more precise. The recess on the inside is made for 3mm. keys but I added 0.5 mm. on either side, to give it some tolerance. It also gives the cryptex a really nice tactile feeling when using it, and the sound is also very nice. I cut out some of the gear tooths to make a round surface where the inner part with the spring would turn, to make sure that the construction is concentric.

In hindsight it would have been better if the cryptex could be turned both ways.

Step 4: Design Features

On top of wanting to have a functioning cryptex, I also wanted one to have on my shelf at home, as a kind of conversation piece. I liked the look from the davince code, where the cryptex looks like a rolled up codex or scroll. So in the final design, I made the end pieces have a bigger diameter than the middle part, I also wanted to have some kind of indicator where the word has to be aligned, so I kept one of the crossbars from the first version, to have it as a display. As a last thing I also made the radius of the letters discs 1 mm larger, to get a better grip, but that also added a nice design feature that made the disc have kind og a checker pattern.

Step 5: Building the Cryptex

The cryptex is made out of laminated sheets of 3 mm. MDF, it in some ways mimicks the same way a 3D-printer works. The parts are laminated using normal fast setting PVA glue, the same stuff one would get in a craft store.

Step 6: Dynamic Disc

The dynamic discs are made out of 3 parts. The gear for the clicking mechanism, the middle part and the disc with the spring mechanism. Afterwards the letters are added. If the disc has to spell out the letter C, the letter C should be in the recess outside the notch where the key goes through, afterwards come D, E, F etc. in the counter clockwise direction, so when the disc is turned clockwise the next letter shown is the next in the alphabet. Then it goes all the way to Z and then from A to the start letter, in this case C. To make sure that the gear align correctly the spring disc is inserted and aligned so the notches for the key align.

Step 7: Static Disc

The static disc is made the same way that the dynamic disc is made, but without the letters. As simple as that.

Step 8: Inner Tube

Unfortunately I have no pictures of assemblying the inner tube, and there is not really that much to it, so hopefully the picture of the final part will do.

Step 9: Final Assembly

This is the most crucial step, after gluing these parts together, there is no going back. The most important thing to do, is to make sure that the discs are in the right order and sequence. The disc has to alternate between static and dynamic, and the letters has to be in the right order. The individual discs are made so they have an inner part on one side and an outer part on the other, this is the case for all the discs, when they are stacked the inner and outer parts will make the discs turn concentric and lock together so they can not be shifted. On the static discs there are finger joints on the inside, that will be mounted on 4 connectors, that also holds the end pieces together and lock all the discs in. The discs should be stacked so the recess aligns, then the assembly bars get some glue and are added on the inside, this is a difficult step because you do not want glue all over the inside of the cryptex, or it will get stuck.

Step 10: Conclusion

After making 3 versions, I ended up with a working, somewhat good looking cryptex. With the added bonus of the click effect. Though I would have liked to be able to turn the wheel in both directions, and there is a bit of twist in the structure, but that is due to the material and because I used glue instead of eg. screws.

<p>Большое спасибо за подробное описание и чертежи, это было очень интересно) Thank you very much, for plans and instructions, it was really intresting. My model made by 4mm plywod.</p>
<p>Hello friend, I like your work. It is awesome. I tried to make my own model but I've failed.<br>Thanks for share your work with all of us!</p><p>I have a question: Can I change the combination of lock?</p>
<p>Changing the combination is fairly simple. In the disc where the letters go there is a notch on the inside where the key slides in. Put the letter you want in your combination in the indent on the outside that sits at the same angle as the notch on the inside. The next letter should be the next in the alphabet, so if you letter on the disc you're working on is g, then h should be the next and so forth. When you reach z add the &quot;a&quot; letter and work your way up to the letter you added first. Do this for all the disc.</p>
<p>So I converted all the dxf files into a solidworks models of my own so I could modify it to my own needs and try to understand how to assemble it before I cut the parts. I have some questions still about the static and dynamic disks.</p><p>I attached some picture of my solid models. For the first picture, what keeps the ratchet mechanism for the letter wheel stationary? Is it glued to the back side of the static disk? if it wasn't secured in some way, then the ratchet disk would rotate, and there would be no clicking sound.</p><p>For the second picture. I still down understand why there is that ring without the letter notches. Is it glued to the letter ring, so it can rotate as well, and make the clicking noise or is there really no reason for there to be that ring, and I can just use another solid static plate in its place to make the assembly simpler?</p><p>Thanks</p>
<p>I am planning to do a 3D assembly and upload it to grabCAD where you can see all the files in the exploded view, and where you can also download the assembly. I hope to have it ready by this weekend.</p>
Hi! where can I find the 3d assembly file?
<p>I designed mine to have 14 letter wheels, and they are all solidworks files. I'm not sure if uploading them here will actually work. If not I can send the files to Da3da1u5 and they can upload them to the instructable if they find them suitable.</p>
Thanks!!! do you happen to have the files in PDF or something to see the images because it doesn't show in here, or maybe send me the files to my email? is that too much to ask? I'm sorry, it's just that I got the pieces like a month ago and I'm still trying to figure out how to assemble it. my mail is analucia.ortizgomez@gmail.com <br><br>thank you so much!!!!!
<p>I attached the 3d pdfs. NOTE: on the static wheel pdf file there are three rings; the ratchet mechanism with the spring arms, the main ring with the 4 nubs, and the ring with the notches for the ratchet mechanism. Now in the main assembly file, the first static ring as show in the file only contains the ring with notches and the main ring, with no ratchet mechanism. This first ring is the only one that is DIFFERENT from the rest of the static ring assemblies. ALL the other static rings are the same as shown in the &quot;static wheel&quot; 3d pdf file.</p>
<p>It's impossible to read those files... </p>
<p>these are just the files i came up with</p>
<p>Thank you for making 3D-files! I am very sorry that I completely forgot to make the 3D-files as I promised. I've been a bit too busy with school lately. If you have any questions, feel free to ask!</p>
<p>And the rings without the letters, are there for the ratches mechanism to work. They are glued to the inner bars, which keeps them from rotating, and the also keep the letter discs in place, so the whole thing does not fall apart, once it has been opened. Think of them like washers on a nut.</p>
<p>I hope it makes sense.</p>
<p>The part of the ratchet mechanism with the spring, is glued to the letter disc. The part with the gears on is glued to the dividers, which are secured with the bars on the inside. So the ratchet mechanism with the gears are static.</p>
<p>This is an amazing project. I loved it and chose it to be my first project. However, I am very new to laser cutter and design programs. I could not manage to scale it for 5mm wood. Is there anyway you can upload this project scaled for 5mm wood? (cdr or dxf extension would be perect). I appreciate it and many thanks in advance.</p>
<p>Hi, sorry for answering so late. I can't redraw everything for 5mm. plywood and keep it the same size. But you can just scale all the parts by 5/3 and everything should work.</p>
I have scaled for 5mm and could upload/share the file. I am still working on assembling though to ensure everything scaled well. The thicker wood does make it a little stiff and clunky when trying to turn the disks; I may adjust the internal click dials a tad. I am hoping to assemble here shortly and happy to update comment thread accordingly.
<p>Hello!</p><p>Do you sell this cryptex anywhere?</p>
<p>I currently do not sell it, but I might be able to do so in the beginning of next year. I have purchased a laser cutter to have at my home. I will notify you when I get it, if you are still interested in buying one. I also have to figure out how much it will cost, either as a kit or a final product. The finished product might be quite costly since it takes a long time to assemble it.</p>
<p>Very excited about this project! Using 5.3mm wood and shortened top five disks for first go around; Updated the design using AI - everything looks in order. All parts cut and looking forward to assumebling next. Has anyone used a lubricant other than WD-40 in between the static and dynamic wheels? Thanks!</p>
<p>When I made it I used sillicone lubricant like the kind one would use on bearing shafts. Afterward I sprayed WD-40 on the inside of the assembled cryptex to make it easier for the two parts to slide together. </p>
<p>The Files you have linked above are corrupted</p>
<p>strange, I tried downloading them and opened them in AutoCAD and it worked fine. What software are you using? I can upload them in another format if you want?</p>
I use Coreldraw I have tried importing both the dwg and the pdf and I get file is corrupt on the pdf and invalid file type of the dwg. Sorry for any inconvenience I'm causing
<p>I have moved the files to the first step. I have saved it in ai. pdf. dwg. and svg. format. </p>
<p>hopefully one of them will work</p>
<p>I am sorry, I tried the pdf and it will not enlarge, if you could do a corel file it would be awesome!</p>
<p>Can you open illustrator files in coreldraw. I can open the file in illustrator and save it in another format for you.</p>
<p>Thank you i was able to get the Ai file to work </p>
<p>Good to hear!</p>
<p>works in eDrawings :)</p>
<p>works in eDrawings :)</p>
can someone convert it to a .svg file plz? thanks
hi! it's me.. again!!! I'm sorry for asking so much, so I already got the inner tube (finally) but that's all I have!! so here are a few questions:<br><br>the dynamic disc goes like the first photo? I don't need anything else?. I see there are 2 different desings for the clicking mechanism, one with 4 dents on the inside and the other one rounded.<br><br>also on the second photo I attached Seems like on the right there is a rounded piece that I don't have!<br><br>also on the 3rd photo for the static disc, I need those pieces only? <br><br>(I'm sorry I'm just very confused because on same steps I can see different parts but in the description says I only need 3. <br><br>thank you so much you have no idea of how many people I showed this and they all loved it but are to lazy to try it.
<p>I am planning to do a 3D assembly and upload it to grabCAD where you can see all the files in the exploded view, and where you can also download the assembly. I hope to have it ready by this weekend.</p>
thank you, that would be amazing if you can upload it. thank you very much
<p>The ring with the small inner diameter, and the four nobs, are joints that are attached to the four bars on the inside that keep the whole assembly together. That ring is glued to the ring with the gears on the inside. </p>
<p>Can someone post photos of the static and dynamic disk assemblies? From what I can interpret, The rings on the outside of the static disk look like they can still rotate because of the ratchet mechanism.</p>
<p>Why not make the ratchet and ring portion of the static disc assembly just another one of the solid plates, so it can not rotate at all? It would mean less peaces, and easier to assemble.</p>
so, I have TONS f questions, one of them is..<br> for the inner tube in guessing one of the two parts from the left is the one I have to use once.<br><br>the thing is, when I sent the file to the laser cut company, they have me EVERY piece, more than 500 so I'm kind of confused, so to have an email or something? it should I pay all my questions here? <br><br><br>thank you!
OK no forget about that inner tube, I did it! my question is directly with the outside .<br><br>on the steps for building the dynamic discs photos 6 and 7 have different parts and I don't recognize which ones are the ones from photos 10 to 12.
I loves it, I already have the parts laser cut. I read somewhere in the instructable something about a video, do you have it? <br><br>thanks and congratulations!
<p>Hi,</p><p>Thanks, it makes me very happy that people like my project. The video should be on the first page of the instructable. If you for some reason can't see it, then here is a link: <iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/_VEz7dVIHsE" width="500"></iframe></p><p>- Daedalus</p>
<p>Why do I need to scale up to use thicker wood?</p>
<p>Because the parts at the current scale only fit together with 3 mm. plywood. </p>
<p>What size of wood should I use?</p>
<p>I used 3 mm. thick wood. But if that is not accessible then you can use whatever size you have and scale the file accordingly. Eg. if you have 4 mm. wood then you have to scale it by 133.33...% (4mm./3mm.*100%)</p>
<p>Also what length and width of wood should I use?</p>