Key Cutting with a CNC Mill


Keys cost like what, $2 to copy at a locksmith? But where’s the fun in that? Here’s an easy way to cut your own keys using a CNC mill!

[Bolsterman] now “works” for a real estate company that rents out various properties. Whenever someone moves out, the locks need to be changed ASAP. They use Schlage locks, which can be re-keyed to any pin combination. New keys are typically cut with a punch or a key cutting machine — he actually had one years ago, but got rid of it. Not wanting to buy a new one for his new job at the real estate company, he decided to see how hard it would be to turn his small desktop CNC into his own personal key cutting machine.

All it took for [Bolsterman] to turn his mill into a key cutting machine was a 3/8th 90° countersink bit with the end ground to a flat approximately 0.055″ across (0.035″ is the width of a factory key, but a bit of leeway makes it easier to make the key). Then you simply zero the mill off of the shoulder of the key, and using the handy Schlage pin chart (included in the original link), cut the grooves!

To automate all of this, [Torrie Fischer] created a python script for generating the GCode  for keys based on [Bolsterman's] technique — it’s hosted over at Noisebridge’s Wiki — check it out!

But if all that seems like too much effort, you could just print a new key instead…


  1. Willy Doyle says:

    I’m not sure where you’ve been buying keys, but the hardware store on the island where I live is notoriously expensive and I’ve never paid more than 75¢ for a standard key or $1 for the fancy brass version.

  2. Galane says:

    Why not just install Kwikset Smartkey locks? All you need to re-key them is the key that currently works the lock, the re-keying tool and the key you want to change the lock to.

  3. Hack Man says:

    They use Schlage locks, which can be re-keyed to any pin combination.

    Just like…. almost all other locks, ever?

  4. Nate B says:

    There’s also a Mach3 setup documented here:

  5. Muchos Gracias says:

    Photos of fingers like this allow determined persons to grab biometrics

    • Trui says:

      That’s why biometric security is nothing more than a gimmick. It’s easy to obtain somebody’s biometric information, and impossible for the owner to change it.

      • Tony says:

        1) Aquire DNA
        2) Grow clone
        3) Fingerprint clone
        4) Realise you can just send the clone to steal their stuff
        5) Profit!
        6) Send clone to work in your salt mine
        7) More profit!

        • mincedmeats says:

          Fingerprints are developed. Twins have different fingerprints. I would expect clones to have different ones also.

          Aside from that your plan is flawless.

          • Tony says:

            I’d considered the fingerprint problem, and I’ll let you know how it turns out when my clone of Bill Gates is done.

            If it does in fact turn out fingerprints aren’t set by your genes, does anyone have any tips for makes someone look old beyond their years?

            I’m trying to avoid the ‘Say Bill, you’re looking good these days’ bit from security. Maybe I’ll wait for those anti-aging trials to start.

  6. ERROR_user_unknown says:

    This is a manual mill not a CNC machine. If he had a script hat automatically cut a keys numbers into a blank at the click of a mouse that would be a CNC. Bonus points for using a 2D or 3D photo of the key to make the copy from.

  7. If you have a CNC machine, you have to be careful with brass, bronze and copper. The leave very fine powder that penetrates all the little nooks and crannys of CNC machines. To avoid problems do very frequent cleaning, but not with compressed air. Compressed air should NEVER be used to clean a CNC machine that machines bronze, brass or copper since it will send the powder all over the machine and end up blocking sensors, rulers the machine.

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