What causes keys to break off in a lock? Broken key extractions and what to do if you need a broken key removed from your lock.

Many people have experienced the frustration and inconvenience of having their key break while attempting to unlock their door, often leaving a portion of the key still inside the lock.  Why does this happen?  The reason(s) causing this phenomenon can be many and varied.

Metal fatigue plays a central role in why keys break. The most popular brands of locks sold today are using keys that are manufactured using soft metal alloys.  In fact, most aftermarket key copies use the same type of key.  This represents the vast majority of keys in use today.  However, even a key made from a higher strength metal can break if it is subjected to abuse.

What constitutes abuse? The most common, but least obvious, is using a key as a door “Pull” when pulling a door or gate open with one hand after opening the lock cylinder. People often do this when one hand is occupied carrying something.  This imparts enormous stress on the key causing the  metal to weaken and snap over time.

 Other reasons or contributing factors may include an opening that is presenting problems.  A door or gate may become difficult to operate due to weather conditions.  Wood doors and frames may expand or shrink due to hot or cold temperatures, as well as, changes in precipitation.  Corrosive elements such as sea air can prove to be significantly more damaging than rust and thus affect performance.  Sagging hinges can bind and misalign a lock.  Also, a dirty and /or malfunctioning lock mechanism can be to blame. Lastly, keys that are on key chains that are left in a lock cylinder may cause damage to both the lock cylinder and the key due to the excessive weight of the sum of the keys on the key ring. 

What to do if your key breaks off into the lock? Obviously, a successful broken key extraction is the best desired outcome in these situations.  The internet is filled with vendors selling broken key extraction tools, and bloggers giving their advice on how to remove a broken key.  One misguided website blogger even advises readers on how to apply super glue into the key way as a means of removing the broken key (We strongly advise against this advice). If a large enough portion of the key is exposed outside of the lock a do it yourself key removal might be performed using a pair of pliers.  But, this best case scenario is not often presented in real life.  

There are situations where the key cannot be removed, at least with the hardware mounted.  The only viable solution might involve sacrificing the lock cylinder or door hardware.  This can only be determined upon a close inspection performed by a professional.  The services of a trusted local locksmith can save you both time and unnecessary expense.

Remember, it is prudent to follow good lock maintenance protocols and periodically clean and lubricate your locks using an approved lubricant.  Also, take immediate action in having a lock or door evaluated at the earliest indication of trouble.  Why wait until your locked out due to a broken key.