The main parts of a door lock include the knob, the dead latch, the rose insert, the strike plate and the key. Technically, only the inside of a knob is directly related to the locking mechanism.
The outside of the knob includes the keyhole, and this is also related to the lock. Sometimes, the dead latch is also known as the cylindrical dead latch. This piece connects into the door itself in order to connect the two door knobs on either side of the door through the latch. The strike plate connects to the door frame, and it is lined up with the dead latch. When the door is closed, the two are connected. The rose insert connects between the inside knob and the door. The key is also an important part of the lock since it is required for the lock to function.
There are many different types of strike plates. The plats are rounded, flat on one side, squared off or even round. Generally, strike plates come with a lock set, but it is also possible to purchase them separately as a replacement. Cylinders are also important parts of the lock because they contain the code that determines if a key opens the door.