What is a deadbolt?

A deadbolt is a locking mechanism where a solid metal bolt extends and retracts manually through turning a key or thumb-turn, with no spring to return it automatically. Unlike a spring latch, which slides in and out of the strike under pressure, a deadbolt requires deliberate action to throw and retract, making it far more resistant to forced entry.

There are two common configurations. A single-cylinder deadbolt has a key on the outside and a thumb-turn on the inside, useful for standard residential doors. A double-cylinder deadbolt requires a key on both sides, often used where glass panels are present or where maximum security is desired. Double-cylinder locks are common on commercial properties and shopfronts across Singapore.

The security advantage of a deadbolt lies in its rigidity and lack of spring action. Forcing a spring latch inward is possible with simple tools, but a deadbolt cannot be pushed or pulled open once thrown. The bolt sits solidly in the strike until actively retracted. This is why building codes in Singapore often mandate deadbolts on external doors for residential and commercial units.

Deadbolts come in various materials and bore sizes, and are typically installed alongside a knob or handle for daily access. Many residential locksmiths in Singapore can install, repair, or upgrade deadbolts to match security and access requirements.