Swiss Army Keys


This isn’t a hack that shows you how to start a car without the keys. It’s a way to ditch the bulky keyring for a set of fold-out keys. [Colonel Crunch] removed the blades from the pocket knife and replaced them with the two keys for his car (one is ignition and door locks, the other opens the trunk). He didn’t take pictures of the process, but he did link to this unrelated guide on how it’s done.

About one minute into the video after the break we see each step in the build process. First the plastic trim is removed from either side of the knife. The blades are basically riveted on; there’s a pin which holds them in and either side of it has been pressed to that it can no longer move through the holes in the frame. To get around this one side is ground off with a rotary tool, and the pin is then tapped out with a hammer. The removed blade/scissors/tool is used as a template to cut the body of the key down to size and shape.  The pin is then hammered back into place before putting the plastic trim back on.

[via Reddit]

56 thoughts on “Swiss Army Keys

  1. Neat, but I’m concerned about the weight this puts on the lock cylinder.
    Years ago, a locksmith (fixing my old ignition switch), warned me that too much weight
    on the key ring was a common source of failure.
    He also warned me against using WD-40 in the cylinder.

        1. As long as your cut off the blades, you can take your swiss army knife on the plane. The TSA finds it and looks so happy, like its the first thing they did all day, then you tell them there’s no blade, then they go back to looking like their wasting their life away.

          1. In response to the corkscrew thing, I flew back through SFO with a corkscrew that had an attached razor knife to cut wine labels. I had forgot it was in my laptop bag, since I bought it on the trip.

            Nobody cared/said anything, but someone had their nail clippers confiscated in the same line.

      1. Yah, it’s cost me one. Had a habit of having every key to everything I ever owned on one straggling bunch with a few keyfobs for good measure. Now I’ve stripped it back to 3 on a small ring for driving.

        1. No, seriously, can you give us some examples? I can’t imagine what you’re lugging around that could actually be a problem. Are we talking keys for six cars, five houses, three sex robots, and the storage locker you use for storing bodies?

          1. My carbiner of key rings:

            My minivan (key & fob)
            * bike lock
            Wife’s minivan (key & fob)
            My house key
            * four different padlocks
            * wedding ring (it is just too big any more)
            Work keys (2)
            * work locker key
            Parent’s house key
            * parent’s garage key
            Baby ‘biner #1
            * ring of a half dozen “rewards” cards
            * two empty rings
            Baby ‘biner
            * three empty rings
            * spark plug gapping tool
            Three keys for bike locks

            Yes, this is a load of keys. I could easily have two or three more work keys, another vehicle (with or without fob), keys for my in-laws, and an LED light fob.

    1. I’ve always had a lot of keys on my keyring. It’s definitely heavier than that little knife. I’m always being told this is going to give me a problem but my life just happens to involve using a lot of keys. If I separated them I am sure I would forget or lose some.

      I’ve put about 200k miles on my Jeep with no ignition issues yet. Hypothetically, if it failed at this point was it necessarily because of the weight or just because it is old and heavily used? The same for the about 100k miles each I put on my previous two vehicles.

      1. It was kinda the “Getting away with it” on Chrysler product ignitions that lulled me into a false sense of security about doing it on everything else…. though their problem would be that on a 100k+ one, you could probably start it just with the blade of the penknife, no need to swap the key in.

    1. Just did one of these myself, already been through two airport security checkpoints without any hitches (besides being asked to fan the keys out for better x-ray coverage).

  2. I like the fact that he left the corkscrew on the knife, you have to admire a man so committed to drunk driving.

    @ Hudson – Your key knife (is that what this thing is called) is far superior.

    1. The weight on the lock and the corkscrew were the first things I noticed too. I wouldn’t want to do it due to the stress on the ignition lock, but having the corkscrew almost makes it worth it. Still… it’s a pretty cool idea even if it’s got some serious drawbacks.

    1. From the photo, I’d say the corkscrew is pretty much “unavailable” while the key is in use. Considerably more unavailable than the various bottle-cap-popper key fobs sold at C-Stores and souvenir shops everywhere.

      But later, you’ll be glad you left that on there: modifying Swiss Army knives is thirsty business.

      Now, on to replacing the saw or magnifying glass with a memory stick.

  3. I will agree with RB that if your car uses a RFID tag this hack will not work unless you harvest the chip from the old key. IF the tag is in a glass ampule then you will be in luck just put the head of the key in acetone and let the plastic dissolve. you might have to replace the saturated acetone a few times until all the plastic is gone.
    Just be ware that if the tag is not in a glass ampule the acetone will dissolve the enamel coating on the antenna wire of the tag and you will be SOL. Good luck.
    once you have the tag you can use a Dremel to carve out a notch on the inside of one of the handles close to the end where the key is.
    Beware that you more than likely can only do this for one car the tags might inter fear with each other.

  4. BTW I think there’s a similar in concept commercial version of this, you can get for your elderly relatives, to put doorkeys in when they start having issues with a weak grip and need the leverage to turn them.

    1. Good luck getting back in when the battery dies in either the phone or lock. I also question the security of the device when they wont even state which encryption algorithm or authentication system it uses; let alone subject it to peer review.

  5. I love it!

    So what if its not necessarily good for the lock, we do plenty of things that are not good for us or the tech in our lives.

    Have fun with it for god sakes! Great job guys!
    Although, do be careful with the police lol….

    Oh… I’m just starting my friends car with a swiss army kn—-key!

    1. you can give that up man. People send us tips from wherever they find them. we’re not going to ignore them just because they’ve been on reddit. Just skim right on past if you’ve already seen it. Just like the people who follow individual hackers skim right past when they’ve already seen things.

  6. Why does he call it “art” in the video? Why is it in black and white? Seems like this guy is desperately trying to be a hipster. I swap a PC component is that art? How about replacing a part on my car? What about installing a extra electrical circuit in my home?

  7. If you don’t like it, are afraid that your lock will wear out faster, or that the nanny state government will throw you into prison and confiscate your keys DON’T DO IT. Otherwise its a neat idea

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