A 3D Printed Cryptex

Once you’ve dialed in your 3D printer calibration settings, you enter the phase of printer ownership where you’re eager to show off what you can make, and you’re sure to impress with [pjensen’s] 3d printed cryptex spinning around in your hands.

If you’re a regular reader of our 3D Printering column, then the behind-the-scenes screengrabs should look familiar: [pjensen] used Autodesk Inventor to sculpt the shapes, staring with the cryptex’s individual rings. After embossing the alphabet across each ring, [pjensen] adds slots into the inner loops for pins to slide through. An outer chamber holds the rings in place and prohibits access to the interior chamber, which is held in place on both sides by an end cap.

Lining up the rings to spell the correct word allows the inner chamber to slide free of the whole assembly, revealing whatever goodies may lie inside. You can follow [pjensen’s] step-by-step guide to build your own cryptex, or just download his model and start printing.

9 thoughts on “A 3D Printed Cryptex

    1. When I read that book and got to the part about the glass vial of vinegar and the message printed on papyrus, which the vinegar would supposedly destroy… I was thinking mount the thing in a jig at an angle then carefully drill up from underneath it into the glass vial while having a strong vacuum to pull the vinegar down and out so it won’t get to the paper. Then the thing could be smashed apart to get at the paper.

      Should be possible with a high speed diamond burr/drill to put a hole through the glass without shattering it. No tempered glass when the thing was supposed to have been made.

      ‘Course the movie left out the second cryptex inside the first one.

      Or alternatively and rather less dramatic, clamp the cryptex into a specially made jig to hold all the parts still then put it on a milling machine and carefully start cutting. Cut an end or on a side?

      Drilling or milling, it would be best to figure out where the vial breaking system is.

      Yet another method. Freeze it to make the vinegar solid. Even if it expands enough to break the vial, no problem as long as the cryptex is broken into while keeping it cold.

      Even without all the fancy tricks, use some time and a Dremel with a cutting wheel to nibble into it. Could probably just slice lengthwise on two sides and split it open.

      Such a security device is only of any real use against someone who cares about preserving the cryptex.

      Now there’s a challenge. Build a bunch of cryptexes (cryptexi?) with the vial smashing “security” feature. Whomever can bust their way in, in the shortest time, while causing no damage to the contents and without breaking the vial, is teh winnar. Special prize for the fastest person who breaks the vial yet causes no damage to the contents.

      1. Except in the olden days you could not see what security device was inside.
        I would think that was obvious.

        And even now you can cloak it against some common scanning devices.

        1. Whatnot is absolutely right. Wait until I ‘secure’ mine with a mild explosive material. Wouldn’t want to be drilling into that and freezing probably wouldn’t help.

          My point was that the cryptex here does not have any way to crush the vial if you get the combination wrong, so they are vulnerable to a brute-force attack.

          I can’t think of a way to get the vial crushing to work while maintaining three things:
          1) Entirely 3D printed (eg No springs)
          2) Freedom of movement of the rings 360*
          3) No indication of correct/incorrect password

          1. Probably wouldn’t help in what way? Freeze the entire thing with liquid nitrogen, and cut through one end of it. Explosives aren’t explosive when they are cold.

            or ‘pick it’ – https://www.youtube.com/watch?v=cvrlreLR7SM

            And really, seeing as we’re dealing with a fictional device, they probably had a fictional way of destroying the contents that was impervious to all non-fictional methods to break into it.

          2. From the book, I was lead to believe that if you tried to use that trick (pull the cryptex with the wrong password) it would give way, making you think it was ‘unlocked’ and that’s what crushed the vial.

            If we were using springs, I could see making a ‘trap’ where if you pull the ends past a certain point it would release a spring-loaded spike into the vial. However, if you solved it, the cryptex would block the path of the spike and prevent damage to the vial. I really want to see the engineering feat of no springs though!

  1. “You can follow [pjensen’s] step-by-step guide to build your own cryptex, or just download his model and start printing”
    only if you have a fancy 3d printer
    from the instuctable “This print requires use of a printer with a soluble support material. There is no way around it … I used a Stratasys uPrint printer, which prints in ABS and a support material”

  2. If the cryptex was printed in PLA one could heat it up a bit and take advantage of its maliability. :-) Actually this is a great way to demonstrate the “print a bunch of entangled parts at once” ability of 3d printing.

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