What is Lock Bumping?

Lock bumping is the name given to a technique which is widely used by locksmiths in order to open pin tumbler locks when people have lost their keys and are locked out of either their home or workplace.

Unfortunately due to the internet it has become public knowledge and it is now being used by burglars to break into properties usually leaving no evidence that a break in has occurred, making insurance claims very difficult.

There are lots of videos on YouTube showing how to make bump keys and how to bump locks, there are also lots of websites on the internet now selling ready made bump keys and bump hammers including Amazon!

Video Demonstrations

The problem has been highlighted on both American and Australian news channels they can be viewed again below.

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What Makes Lock Bumping Possible?

A typical pin tumbler cylinder usually consists of five main parts, the body, the plug, the key way, upper pins, lower pins and springs, when the correct key is inserted into the key way in the plug the upper and lower pins will line up at what is known as the shear line, this then creates a slight gap between the body and the plug which will allow the plug to rotate inside the body and open the cylinder.

Lock bumping involves using a specially cut key where all the grooves on the key have all been reduced to their lowest point.

When inserted into a cylinder with a matching key way and struck with a suitable object it allows the transfer of kinetic energy through the upper pins and into the lower pins this action allows them to all jump up at the same time and then for a split second settle at the shear line, if the key is turned very slightly at the right moment when the pins clear the shear line it will allow the cylinder to open just in the same way as it would do if the correct key was inserted and used.

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Lock Bumping Reference

More information can be found on the following websites: