Understanding the important parts of a door knob will benefit you if you are trying to troubleshoot when the knob breaks. It can also be useful to know the parts of a door knob if you want to become a more informed buyer.

Whatever the reason you want to understand the components of door knobs, this article will break down the essential door knob parts and explain the way each one works and how it fits into the overall mechanism.

Parts of a Door Knob

Knob or LeverRosette/BackplateSpindleLatch or DeadboltDeadlatch/Deadlocking plungerStrike plateScrewsKeyholeThumb Turn

Definitions for Door Knob Parts

Standard door knobs have eight main components. By understanding the door knob parts names, you can better maintain your door’s most important pieces of hardware.

Knob/Lever

Most door knobs have two knobs or handles, one on either side of the door. Manufacturers shape the knob and handles in ways that are decorative and practical. Most knobs have a spherical shape and most levers are long and flat, extending off to the side of the door.

Interior doors may or may not have a lock component. Privacy door knobs will have a simple locking mechanism that you can operate on one side. Dummy door knobs do not feature a lock of any kind. For exterior doors, the outside door knob will feature more extensive locking mechanisms. The most popular locking system for standard exterior doors is the pin tumbler cylinder.

The pin cylinder includes a cylinder with a set of pins. Manufacturers create a key to correspond with the pins. When you insert the key into the cylinder, the pins move to the correct position and open the lock. Pin cylinders come in single and double rows. Single row cylinders are common for most standard door knobs. Look for a double row pin cylinder for high security needs.

Door knobs feature a wide range of materials including brass, pewter, glass, porcelain, stainless steel, chrome, nickel, wood, and iron.

Rosette/Backplate

A rosette (or rose) or backplate (or trim plate) covers the hole in the door where the spindle connects the door knobs. Rosettes and backplates are ornamental features that improve the look of the door by covering the opening in the door and the knob spindle. They also complement the look of the door knob with decorative designs. Some feature elaborate ornamentation and others are plain. Typical rosettes are round or oval while backplates are square or rectangular.

Interior rosettes/backplates feature set screws. You can remove these set screws to take off the rosette if you need to look at the door knob components. For safety reasons, exterior door knobs do not have parts that anyone can disassemble from the outside.

Spindle

The spindle is the rod that projects into the hole in the door. The spindle connects the knob to the latch or deadbolt mechanisms inside the door. The knob spindle allows you to turn the knob or lever and activate the spring bolt in the latch or deadbolt. As you twist the knob, the spindle turns and moves the latch in the same direction and opens it.

A spindle is metal and crafted in a square, round, or splined formation depending on the type of lock or latch. Square spindles are the most common shape in standard door knobs. Splined spindles have raised ridges that make the spindle more challenging to remove from the door, so high security door knobs often use splined spindles.

Latch or Deadbolt

Latches and deadbolts are door handle parts that allow you to lock the door. When someone turns the knob or lever, they activate the latch. The latch mechanism contains a spring loaded bar which goes from the exterior edge of the door into a hole in the door frame. When you turn the door knob, the spring loaded bar retracts and allows you to open the door. Releasing the door knob will allow the spring mechanism to push the latch back out.

You can activate a deadbolt with a key or a thumb turn. A deadbolt is a valuable security measure because they cannot be easily picked or bumped open. Both components add greater security to door knobs, but experts consider deadbolts more secure. Interior doors have just a latch component, while exterior door knob systems utilize both latches and deadbolts for greater security.

Deadlatch/Deadlocking Plunger

A deadlatch or deadlocking plunger is an added security door knob mechanism on exterior door knobs. This small bolt sits on top of the knob bolt that extends into the door frame. This secondary bolt will open and close when you manipulate the knob, but they are more secure because they automatically lock when you close the door. Deadlatches require a key or a thumb turn to open.

Strike Plate

A strike plate is a thin metal plate that installers attach to the door frame to create a reinforced hole for the knob bolt to extend inside. This plate makes it more difficult for intruders to force open the door. Strike plates also protect the door molding from the wear and tear of the door bolt and guides the bolt to the optimum position in the door frame.

The strike plate is one of the most seemingly inconsequential parts of a doorknob, but it is vital to the good functioning of the door. A lack of care in the installation of the strike plate can cause the door not to close properly. This will prevent it from locking well and decrease your home’s overall security.

Setting Screws

Setting screws function by holding knobs/levers and spindles in place. It is important to secure the knob tightly against the door so that when you turn the knob, the force propels the bolt to turn rather than the knob itself. You can find setting screws on the interior side of the door for security reasons. Tighten them as they require with a small screwdriver.

Keyhole

A keyhole is one of the parts of a door knob that you can find on some but not all doors. All exterior doors will have a keyhole on some part of the door knob, either the knob or a mortice lock section.

The keyhole has two main elements: the keyway and the tumbler mechanism. The keyway is the opening through which you insert the key to open the door. The tumbler mechanism inside the knob is activated when someone inserts and turns a key. There are several types of tumbler mechanisms including a pin tumbler, a wafer tumbler, a lever tumbler, and a disc tumbler. The most common tumbler in standard door knobs is a pin tumbler.

Thumb Turn

A thumb turn is a mechanism that some door knobs have that allows you to lock the door by turning a bolt rather than using a key. Thumb turns are attached to the door knob through the latch mechanism. When you rotate a thumb turn, it turns the spindle, shifting the position of the bolt. For safety reasons, only the interior side of the door knob has thumb turn mechanisms.