lockset

Lockset is a hardware assembly installed on a door to operate a latch and, in many cases, to control access. A typical lockset includes a door knob or lever, a latch or bolt, a spindle that connects the knobs/levers through the door, a strike plate on the door frame, and mounting hardware. Exterior locksets may include a keyed cylinder and a deadbolt; interior sets often omit a key.

The latch or bolt is spring-driven and retracts when the handle is turned or a key is used. Backset measures distance from the door edge to the latch center; common backsets are 2 3/8 inches or 2 3/4 inches in the United States. The lockset fits into cross-bore and edge-bore holes and engages the strike plate on the frame.

Locksets come in several styles, including cylindrical (or tubular) locks, mortise locks, and multipoint locks. There are privacy locksets for bedrooms and bathrooms (operated by turn button or emergency release from inside), passage locksets for non-locking interior doors, and dummy or non-functional sets used for decorative purposes. Exterior locksets often pair a latch with a deadbolt for added security.

Standards and ratings: in the United States, locksets are rated by BHMA/ANSI. Grades 1, 2, and 3 indicate durability and security levels. Faceplates, finishes, and corrosion resistance are specified by these standards. Installation depends on door preparation, including bore sizes (usually a 2 1/8 inch cross bore and a 1 inch edge bore) and alignment with the strike plate.

Materials and finishes vary; common materials include brass, steel, and zinc alloys, with finishes such as brass, satin nickel, and black oxide. Proper installation includes ensuring proper latch alignment, smooth operation, and periodic maintenance to prevent sticking or key-in-device issues. Locksets are widely used on interior doors, and exterior doors often require higher-security hardware.