A bump key is a specially crafted key that is commonly used to open any lock the key blank will fit in. Criminals use bump keys to quickly open key based locks that utilize a cylendar and tumbler design without causing damage or leaving any other indication that the lock was tampered with. Criminal use of bump keys has been going on for decades so it is not a new technique of opening locks. Lock owners have been in the dark about how easy it is to defeat their home lock systems for a very long time.
How Does a Bump Key Work?
Using a bump key is pretty simple, but there are a few things you have to do to get the key to work properly. First, you full insert they bump key into the lock to be opened. Next you pull the key back one click. Then you place a slight amount of pressure on the key by turning it slightly, or pressing against it, so when the tumblers are aligned they are not permitted to fall back to their original position. Finally, you strike the key with a screwdriver handle or some other small object while you keep pressure on the key. If your bump key is properly cut, the lock should easily open. If it takes more than a few tries to open the lock, you are doing something wrong, or your key is not cut properly.
The Dangers of Using a Bump Key
Locks are not designed to use the cut pattern bump keys use for its tumbler positions. It is a trivial matter to recognise a bump key as device to open locks illegally. The key also needs to be cut in a way that the slope on the front side of the key is not too steep, or the key won’t insert into the lock properly. Also the slope on the back side of the key also cannot be too steep or you will not be able to retract the bump key from the lock. It will be quite a challenge to explain to a locksmith what you were doing if the key does get stuck in the lock. Bump keys are usually considered to be a lock pick, so if lock picks are illegal to possess in your geographic area, the bump key is probably also illegal. Never carry around a bump key with you unless you have specific intent to use it.
Testing a Bump Key
Always test a bump key on an open door or a similar lock that cannot easily be observed from the outside. This way, if the bump key does happen to get stuck in the lock, you can dismantle the lock to remove it.