People have been passing through doors, turning those door knobs,but never wondered how these work. Whether these are made of any material such as wood, metal, or glass, and whatever its size and / or shape, its parts can simply be segregated into three groups: the external parts, internal parts, and the dead latch mechanism.

The external or outside parts are the most visible to people. First are the two actual knobs. These are usually circular in shape, and are placed on both sides of the door, one on each side. Normally, for those systems with locks, one of the knobs has the keyhole (usually the one placed on the outside of the room), and on the other one, the locking mechanism (placed on the inside of the room, that looks like a button that people will press in order to be locked). The outside knobs are the things that once turned, unhinge the whole system, and open the door. The other external part is the stem, which is the "protector" of the internal parts. This has two main purposes: to cover the spindle (discussed on the next paragraph) and to connect the knobs to the base.

The internal or the hidden parts consist of the two or three screw posts and the spindle. The screw posts are the ones connecting the outside knobs from the inside. On the other hand, the spindle, is considered as the heart, and is located at the very center of the whole system. This is the enabler and / or the disabler in turning the outside knobs and makes the whole door knob system work. It is the one being locked when the locking mechanism on one of the knobs is triggered, disabling the other knob (the one with the keyhole) to be turned.

The last part is the dead latch. Others call it latch bolt. This is small in size (usually an inch) and usually made of metal. Whenever the knobs are not turned, the dead latch keeps the door closed. It is the one that is being inserted into the carved portion of the strike plate (placed adjacent to the Door Knobs). It sticks out when the knobs are unturned. It then goes inside, being caught by the spindle, when one of the knobs is turned. That is why it is considered the "spring" of the system since it moves back and forth whenever the outside knobs are used.