Lock bumping has been around for decades and is one of the easiest ways to open a lock without damaging the mechanisms inside.  Locksmiths have been using the method for years, and even other personnel like fire, police, and repo men will use the method as a way of getting through a locked door without having to bash it down.  The process is simple enough to understand with a basic idea of how the locks work.

Inside of a lock there are a series of pins in a row (with an extra pin resting on top).  As you slide in the key, the pins are pushed up to the correct height to allow the second pin resting on top to go past the “shear line”.  The shear line is edge of the plug, and without the correct key inserted into the lock, the pins cross the shear line, preventing the plug from turning.  By inserting the correct key into the lock, the pins no longer block the plug from turning, allowing the handle to be turned and the door to be opened.

Bump keys work with help from precise cutting and a little bit of force.  A key blank designed to fit into a specific brand of lock is first cut very simply so that the teeth are low enough to not push against the lower pins.  The key is then inserted into the plug up until the second to last pin, and with a little bit of torsional pressure, the keys are struck (or bumped), transferring energy through the bottom pins into the top ones.  When this occurs, the lock can be opened, and it is done without damaging the lock.

In order to transmit the right amount of pressure into the pins to bump the lock correctly, the teeth are cut according to the lock manufacturer’s specifications of what the lowest depth of pins would be.  Often, there are even kits available with different lock’s cut into bump, or “999” patterns, to be used for lock bumping.  But they can just as be easily be cut by using a blank key from a hardware store.

Lock bumping has been a common way for lock smiths and other officials to gain entry without the use of heavy force or a multitude of tools.  It can be done with just a key and an object to apply force, rather than an entire kit that is often necessary for locks.