Jan 18, 2015 | By Alec

Does it ever happen at a convenient time? I suppose it’s central to the nature of keys that if one breaks while trying to lock, unlock or start something, it’s a bad time. After all, who touches a lock when they’re not trying to go somewhere, go to sleep or come home? And locksmiths can be a bit pricey, as I’m sure you’ve noticed.

Fortunately, the creative duo behind the Smith│Allen studio has been working on a 3D printed solution for this exact problem, so you’ll (theoretically) never have to worry about breaking a key again. Simply design and 3D print a new one! Now why you’d turn to 3D printing to solve this problem is beyond me, and as you’ll see in a moment it isn’t fool-proof either, but it nonetheless illustrates the unique manufacturing potential of 3D printing.

As they explained, a common disaster recently struck them too. ‘Disaster! My only copy of the my car key broke, I park on the street and have to move my car by Saturday 9AM today is Friday and I have to go to work. What to do? I could call an auto locksmith or take it in to the dealer but that would be expensive and take time. There has to be a better way.’

They have therefore worked on an upgrade to bring this key ‘into the 21st century’ by designing a new copy using free Fusion360 cloud-based 3D modeling platform (sign up as an enthusiast to gain access for free). Now this will require a bit of modeling work and a highly accurate printer (the key needs to fit, after all), so this project might not be for everyone. Smith│Allen relied on a Objet Connex 500 from Stratasys, but those aren’t exactly cheap. Alternatively, you could try Shapeways though that would mean sharing your key designs with strangers. Perhaps not the most comforting thought?

Nonetheless, their project is interesting. They initially made a series of photographs that properly capture all the key’s details and profile. To do so, ‘Lay the key down and get it as flat as you can. Try to get the light as even as you can. Take the photos from a bit further away than you think you would need to, taking them further away means the profile will appear 'flatter'. The flatter the image the more accurate the trace will be.’

These photos can be used as your basic workspace in Fusion360 software, though you’ll also need to do some extensive measuring work with a pair of calipers to add all the details. In a nutshell, this requires several steps: ‘Use the calipers to measure the length and width of the key. Make a new sketch then a rectangle of the basic size of the key. Measure the keys thickest point and extrude the sketch to that volume.’

Next, you’ll need to add in all the grooves one by one, measuring them with your calipers and recording them in a 2D sketch. Check out Smith│Allen ‘s full guide for this on Instructables, but the process will entirely depend on the shape of your own key. This whole process can be very time-consuming, so beware. It might also take several iterations to get all the details right.

However, once you’ve reached a satisfactory stage, you can save your design as an STL file and 3D print it on your printer. Mind you, keys are typically subjected to a lot of strength and wear-and-tear, so make sure you the strongest possible filament. Also make sure to try it in a non-essential lock first, as your key can easily break off despite all your work – Smith│Allen’s key did. ‘I just went for it, and it worked...sort of. The key fit the lock and was able to turn, it broke when turning the additional bit to start.’

Not every story has a happy ending...

Truth be told, this guide doesn’t even have a happy ending, as Smith│Allen hasn’t yet succeeded replacing their key with a durable alternative. But it’s a very impressive and creative project nonetheless; why shouldn’t keys be 3D printed? But perhaps more can be achieved with a metal 3D printer…


Posted in 3D Printing Applications


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Nick wrote at 5/1/2017 9:14:35 AM:

The scheme I have seen is (1) 3d print the key, stick it in the lock (2) hold the broken key's chip near the key (3) turn the lock with a lockpick's tension wrench. The key is there to hold the tumblers in place. The turning force is actually supplied with the tension wrench. The local automated key cutters have you put the key on a stage and they pick the blank and cut the key from a picture, while never touching your key. All done from an automated version of this. This is easier to do if you know the parameters - standard locks have tumblers in standard lengths and they are a standard distance (based on the cylinder) apart, if the machine is programmed for the blank it is easier to get it right from a picture.

De_Inquisition wrote at 10/31/2015 1:35:59 PM:

I'm currently working for a company which duplicates keys for customers. was just researching the 3D printing capabilities and if any application can be applied to keys. this write up has told me that it isn't a good idea right now :-( lol. maybe we'll get stronger cheaper material to use for keys in the future with 3D printers.

@LocksInPhoenix wrote at 5/27/2015 5:46:16 PM:

Interesting and cool indeed. This nicely highlights the abilities of a 3D printer. But not very useful if your car is newer than 1997 and you have a transponder chip imbedded in the head of the key. Your car won't start without having the chip programmed to the vehicle.. and I don't think you'll be printing transponder chips any time soon.

Chris wrote at 1/19/2015 4:12:44 AM:

And this is why you should never post photos of your keys on the internet

Idr Ive Yourcar wrote at 1/18/2015 12:09:58 PM:

The plastic key can be used to cut a metal key. Also the plastic key could have a metal spine and top to take the twisting force. Why does everyone assume the whole thing has to be printed ? A 3D printed key cutting machine would be far more useful.

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