Written By: Ehsan Jahandarpour

A dead bolt, dead lock or deadbolt is a locking mechanism distinct from a spring bolt lock because a deadbolt cannot be moved to the open position except by rotating the lock cylinder with the key. The more common spring bolt lock uses a spring to hold the bolt in place, allowing retraction by applying force to the bolt itself. A deadbolt can therefore make a door more resistant to entry without the correct key. A deadbolt is often used to complement a spring-bolt lock on an entry door to a building.