How to Make a Bad Key Work

Over the past few weeks I’ve made several hundred dollars unlocking doors where somebody had a working key but it was so poorly copied that it would only work if you knew how to make it work.

First before doing anything rash try slowly pulling the key out while trying to turn it. If that doesn’t work, put a little bit of rotational pressure on the key and vigorously shake it up and down. Light pressure works best.

  • Don’t pee in the lock.
  • Don’t turn your key really really hard until it breaks off in the lock.
  • Don’t drill the lock (unless you have some good drill bits and a big battery and a lot of time).

Working with locks every day I’ve become very skilled at getting bad keys to work. In fact I have to be careful that I don’t overlook a problem with a key that I mindlessly overcome because it is second nature. It occurs to me that maybe I should share these techniques with the public in the hopes that those with more time than money can save themselves $100.

The most common problem by far is that a key is copied by somebody who hasn’t cleaned their machine or hasn’t calibrated the machine in years or both. The result is that the key blank will be placed in the clamp with a bunch of brass shavings underneath it, pushing it up 5-10 thousandths of an inch. This will yield a key that will sort of work if you are used to using bad key copies but will confound people who are used to keys that work properly. The way to make such a key work is to pull the key out slightly as you apply rotational force to the key. The reason this works is that pulling the key out actually lifts the pins up to their proper height because keys are cut at about a 45 degree angle and as you pull the key up the pins are riding up that 45 degree cut. You can even push the key up towards the top of the lock with some degree of success, depending on how tightly the keyway was manufactured.

This same technique will work on a lock that is very old and worn. Over the decades the face of a lock will get worn where the key touches it. The wear will get deeper and deeper as people keep shoving their key into the keyhole. Eventually the wear may reach a point that the key is moving beyond the place it should stop and the pins will begin traveling up the 45 degree incline of the cut they should be sitting at the bottom of. In this scenario the pins would actually be lifted above the shear line. A lock with this much wear may have pins that are worn down too, meaning that the two kinds of wear may actually counteract each other. I have seen these locks in the field though where the key actually has to be pulled out to where it would have stopped if the lock wasn’t worn away there to work properly.

The hypothetical owner of a house may subconsciously learn how to overcome bad key copies and use the same terrible keys for years but then ask their friend to walk their dog during a vacation, instructing them to use their poorly copied key. The friend will attempt to use the key but not knowing the trick, they’ll be locked out. They will call the owner who will instruct them to “jiggle it around a bit” but will be unable to communicate the trick that has been committed to muscle memory and is not even a conscious effort anymore. If that doesn’t work, they’ll call me and I’ll open the door for $75.

Jiggling keys around (shaking the key while it is inserted in the lock) is also very useful, especially if the key is used in a masterkey system or is a cheap doorknob like a Defiant. Shaking the key around while applying rotational pressure will cause the pins to get caught at the shear line if you’re lucky. If the key is cut properly it will raise pins to the shear line just by inserting the key all the way into the lock.

Another problem that sometimes occurs that is usually in the households of old men with a can of graphite: the pins in the lock will get stuck above the key. The graphite will form a sticky paste that will overcome the power of the springs above the pins. When this happens you stick your key in, the pins rise up above the key cuts, but they do not go all the way down into the cuts of the key. This can be overcome by rapping the lock lightly with a screwdriver handle. Also spraying liquid lubricant in might help. Be careful if you do because graphite makes a terrible mess when it is suspended in a liquid. It will streak down your door and into your carpet, all over your hands and get on your clothing. Don’t use graphite in the first place. Use a PTFE lubricant.

And yet another problem is when a key is cut at the proper depth but the person copying the key doesn’t use the correct part of the key to gauge the lateral distances for the cuts. This most often occurs with Kwikset keys and untrained workers who don’t know that one must gauge the key by the shoulder. Some Kwikset keys have stops at different points on the bottom of the key in relation to the top of the key. A hurried hardware store employee or somebody who just doesn’t care will gauge the keys by the bottom of the key and the cuts will be too far out on the key. This means that the key might still be usable by pulling the key out while trying to turn it.

Of course humans will figure out a way to mess things up and there are many more ways to improperly copy a key including using the wrong blank, using blanks that don’t conform to OEM spec, etc. The main thing is to try the key before you need to use it. I’ve done more than one lockout where the customer had blithely trusted a key and put it in their secret key hiding spot only to discover in their time of need that the locksmith in the parking lot kiosk hadn’t properly copied the key and it didn’t work.


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Bjørn Madsen

I am the Seattle locksmith you've been looking for. High Quality work at a reasonable price delivered in a timely fashion.