You're just leaving the house and you turn to lock the door, or you're running late and jump into your car and twist the key. All that turns with your hand is the head of the key while the shaft is stuck in the lock. Now what? Call a locksmith and figure on a couple of hundred dollars and possibly an hour of time for a service call? Phone a tow truck to take your car to the dealer where you'll probably be looking at a few hundred dollars to get your ignition working again? You just might have another option; with patience and some contrived tools, you may be able to get that broken key shaft out of the lock yourself.
Note: Take care using these methods as you do run the risk of damaging your locks while trying to extract the broken key.
Getting Your Key Out
The concept is quite simple. First, you want to slide a strong, thin piece of metal in beside your key shaft to hook and pull it back out of the lock. Once you've got the end sticking out, you will grab the protruding piece of the key and pull it out the rest of the way. The piece of a coping saw blade (or other thin saw blade) is good for getting the key started, since the teeth on a saw blade all point in one direction and can grab the key shaft.
Start by giving the lock a quick spray of lubricant like WD-40 to make it as easy as possible for the key shaft to slide out. Now insert the piece of saw blade into the keyway (making sure the teeth on the blade are pointing towards the back of the lock). Take a look at a key right now. There are probably some grooves running the length of the shaft and some teeth sticking up. On one side of the teeth the key shaft is thinner or cut back—you want to slide your saw blade in along this area. Car keys that can be inserted either side up also have a thin side on each edge of the key. Grab onto the key shaft by twisting your saw blade a little. When it gets a grip, try to slide the shaft out of the lock.
Once you've got a bit of the key shaft protruding from the lock, use needle nose pliers, tweezers, or even a set of nail clippers to grab on to the shaft and pull it all the way out.
If the broken key shaft won't budge, the lock may not be in a "neutral" position, the tumblers inside the lock still holding onto the broken piece. If the lock isn't in a neutral position, you can probably get it aligned by turning it with your saw blade in the lock.
Once you get the broken piece out, don't just throw it away. A locksmith can usually make a new key from the two pieces of the old key.
Some Quick Tips
The old saying, "an ounce of prevention is worth a pound of cure" certainly applies here. Take a look at the keys you use every day. Keys will start to weaken and crack where the shaft joins the head just from regular use. If you can see any tiny cracks in your keys, get new ones cut and get rid of these old ones. Keys made from soft metal like aluminum are particularly prone to breaking. Additionally, lubricating your locks on a regular basis (with a proper lock lubricant) will make sure they turn easily.
On another note, hardware stores used to sell lock picks made with a tiny hook on the end; some may still do so.
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Murray Anderson is an experienced freelance writer with numerous articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com.