3 Lever Mortice Deadlock

Deadbolts, locks and keys secure doors, gates, sheds and outbuildings. This category covers nightlatches, mortice latches and deadlocks, profile cylinder deadlocks, padlocks and padlock sets keyed alike, security bolts and thumbturns, gate latches, latch handles and key blanks.

Main types

• Nightlatches: rim locks fitted to the inside face of a door, opened by key from outside and a knob from inside. Double-locking versions can be deadlocked with the key.
• Mortice locks and latches: fitted into a pocket cut in the door edge. A deadlock has a key-operated bolt only; a latch holds the door shut with a sprung latch bolt.
• Profile cylinder locks: use a separate cylinder that can be changed without replacing the lock case.
• Padlocks: closed shackle and shrouded designs leave less of the shackle exposed. Keyed-alike sets open with one key.
• Gate latches and bolts: ring, spring and self-locking latches for timber gates.

Standards and security

BS 3621 covers thief-resistant locks and is often named for timber external doors; check which standard your home insurance asks for, as requirements vary between insurers. Profile cylinders are made to BS EN 1303, and some carry the TS 007 star rating against attack. Mechanical door locks and latches are graded under BS EN 12209, and padlocks under BS EN 12320.

Replacing a lock

A replacement needs to fit the existing cut-outs, so note the lock type, case size and backset (the distance from the door edge to the centre of the keyhole) before choosing. Key blanks are matched to a particular lock or padlock, so check the reference.

For handles and hinges, see door handles, hinges and accessories; for alarms and other security, see safety and security.