Complete Guide on 12 Essential Door Knob/Lock Parts: Names & Diagram

A doorknob is a mechanism for opening and closing a door. The typical door knob is made from a bolt or spindle that passes through it and sits essentially over a hollow, circular tube. It is commonly found on various types of doors, including exterior doors of residential and commercial buildings, internal doors, cupboard doors, and vehicle doors. Door handles come in diverse designs tailored to specific purposes—many handles, especially those for commercial and residential doors, feature integrated latching or locking mechanisms. But one question arises: why it’s essential to know about the door knob or door lock parts. The answer is that when our door knob or lock is not working correctly, we must show it to the repair person. He might suggest replacing the entire door lock. If anyone knows about every part of a doorknob, he can replace only the damaged part. So it will save lots of money along with valuable time.

In this article, we’ll explain the anatomy of a door knob, the different parts, and their names, and provide helpful diagrams. This knowledge can be valuable when encountering doorknob or lock issues.

Door Knob Parts Diagram

Door Knob/Lock Parts, Names, and Diagram

Door Knob Parts Names

  • Cylinder or Lock Body
  • Bolts
  • Strike Plate
  • Keyway
  • Rotor
  • Cotter Pin
  • Spring
  • Stator
  • Trim
  • Face Plate
  • Spindle
  • Door Knob or Handle

Parts of a Door Knob/Lock and Functions

When everything functions smoothly, we rarely stop to think about the components that make up a door knob. But, when issues arise like a door not locking properly, a misbehaving knob, or when you want to upgrade, knowing the door knob parts make work becomes easy.

So, let’s look at all the parts of a door knob together with its location and functions. Understanding how they work and which parts might need fixing will be helpful if you ever need to work with one.

Cylinder or Lock Body

The cylinder is the central part of the door lock where we insert the key. This cylinder is also called a lock body. The lock body consists of the total locking mechanism of the door lock.

It consists of a spring and several spring-loaded pins. To open the lock, we need to insert the correct key with the right pattern in the correct direction.

When we insert the right key in the keyhole, the uneven edge of the key pushes the pin to fit the height of the key in the lock body. All pins move at the correct place, which causes the cylinder to open and allows the bolt to move.

It causes the door to open. Cylinder locks are one of the common examples of exterior locking arrangements.

Bolt or Latch

The bolt or latch, a metal component, extends from the door and engages with the door frame when the cylinder is locking. It disengages when the cylinder is unlocked.

The function of bolts is to permit one to stop or open the door. There are many types of latches used in a door locking mechanism.

Below are some common examples of bolts or latches.

Spring Bolt

The spring or latch bolt is a spring clip that holds the bolt in place. When the door is in the unlock position, the spring clip compresses.

It helps the bolt to move in the lock body, which causes the door to open. When the spring releases, the spring retains its original position as previously.

The spring bolt automatically locks itself without any key while shutting the door. This type of locking mechanism is beneficial when we rush the leave the house and helpful for those who need to remember to close the door every time.

The main drawback of this door lock is that there are chances of forgetting the key inside the house.


The deadbolt is one of the secure locking mechanisms because it does not use any spring. This deadbolt door lock gets open or closed by the correct key only.

Barrel Bolt

The barrel bolt positions the long metal cylinder horizontally and guides it with the thumb when locking or unlocking the door.

When we lock the door, the barrel bolt engages with the hole in the metal cavity, and when we unlock the door, we draw the barrel bolt out from the faceplate.

These barrel bolts are used on the inside of the bathroom door. But there are better-locking mechanisms for an external lock because the door breaks when someone kicks the door hard.

Hinge Bolt

Hinge bolts are available on the sides of the door, providing additional security to the door lock. It helps to prevent the door from opening when someone tries to enter forcefully.

The wooden door features a hinge bolts mechanism, where a hardened steel bolt extends from the door frame to lock the door by fitting into a corresponding hole.

Hook Bolt

These types of locking mechanisms are commonly found on sliding doors. They use a spring bolt on a pivot with a hook-shaped head.

Strike Plate

The strike plates are made up of metal attached to the door at the same height as the latch. The strike plates contain an opening into which the bolt engages when the door is in the locking position, whereas the bolt disengages when the door is in unlock position.

The lip guides the bolt in the correct direction in some strike plates. Strike plates are the parts of a door lock that are easy to replace when damaged.


Keyway is the slot or opening in a cylinder or lock body where we insert the key and rotate it in the right direction.


The cylinder of the door lock houses the rotor. When we insert and rotate the correct key into the keyhole, we turn the rotor to release the bolt.

Cotter Pin

The Cotter pin is the only reason to turn the rotor when we insert the correct key in the keyhole of the door lock. Its material is metal that undergoes pressure applied from the spring.

It is aligned in the grooves and forms the correct pattern to move the bolt.


The stator is the additional part of the door lock which interacts with the rotor and enables the rotor to turn when the key aligns in the correct grooves.

Trim or Rose

The trim is another part of metal that extends from the door and contains the keyway. Not every type of door lock has it, but the cylindrical lock commonly includes it. It is positioned before the doorknob.

Face Plate

It is a metal plate that someone fixes to the external vertical edge of a door. It has a hole through which the bolt can pass and lock into the corresponding strike plate on the doorframe.


The spindle is a part of the door lock that connects the door handle or knob on both sides. A spindle is a square rod that releases a latch inside the door.

It allows the door to open when the doorknob rotates left/right, and the handle is pushed downward.

Door Knob or Door Handle

The doorknob or Door Handle is the essential part of door locks. The exterior part of the door lock is referred to as an exterior doorknob or handle, while the interior part is known as an interior doorknob or handle.

This interior or exterior doorknob or handle fits separately or has a locking frame. When the doorknob rotates toward the left or right, it opens the door, whereas the handle pushes downward to open it.

The doorknob looks more attractive and improves the aesthetic of our door also.


The knob or handle, the most visible part of the door, serves not only as an aesthetic element but also as the primary means of interaction. Understanding the parts of a door knob enhances our knowledge of design and engineering. It helps us to choose the right door knob for our homes. Its diverse range of shapes, materials, and finishes allows for endless possibilities in completing any interior style.
Suppose you renovate your home, redesign an office, or replace a worn-out knob. This article helps you to choose a suitable door knob to elevate the aesthetics and performance of your doors.

What are the parts of a door knob or door lock?

Cylinder or Lock Body
Strike Plate
Cotter Pin
Face Plate
Door Knob or Handle

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