Doorknob

A doorknob is a popular type of handle used for opening and closing a door. In its simplest form, a doorknob provides only a place to grab so that the door may be pulled toward oneself. On most modern doors, however, doorknobs can be turned to operate a latching mechanism, which normally holds the door closed. A doorknob may also have a lock built in, though in some cases it is beneficial for the lock to be separate.

Doorknobs can be difficult for the young and elderly to operate. If a person lacks a firm grip a doorknob must sometimes be operated using two hands. For this reason doors in most commercial and industrial buildings and in many households now use an operating lever, rather than a doorknob, as the lever does not require a firm grip. Levers are also beneficial on doors with narrow stile widths where the reduced backset leaves insufficient space to comfortably turn a doorknob.

Most household doorknobs use a simple mechanism with a screw-style axle (also called a spindle) with two flat ends, to be threaded through the door latch, and two knob sides. Knobs are attached on both sides by screwing them directly onto the axle, and then securing one or more retaining screws on the side of the knob's axle. Doorknobs that lose traction can frequently be repaired by replacing the screw, which prevents them from slipping on the axle.

The location of the doorknob on the door may vary between a few centimeters away from the door frame to the exact center of the door, depending on local culture or owner preference. The distance from the edge of the door to the center of the doorknob is called a backset .