One of the most popular and widespread type of lock on the market is the deadbolt; the reason for such popularity is that the deadbolt is a sure thing. You can be sure that this mechanism will work. The way it works is quite simple, one component (the door) that is hinged is connected to an immovable object (the wall) using a strong shaft that connects the two together.
There are two very important aspect of the shaft, one is the length that allows it to penetrate into the immovable frame, and the other is the strength, which makes it less possible to cut through or break into.

An understanding of physics will give you an idea of the value of the deadbolts long shaft. It is important to have the necessary pressure to push this shaft through the immovable frame that increases in proportion of its depth embedded in the frame. If you are not into physics that important thing to know is that, if your shaft pushes one inch or more past the strike plate then it would take that much more pressure to break through the door.