What is a swing bolt lock?
A swing bolt lock (in Dutch zwenkschootslot) is a lock whose bolt, the part that actually secures the door, does not slide straight out of the lock but swings out with a rotating movement. It is mainly found in external doors made from profile systems, such as aluminium and steel doors.
Why a swinging bolt?
In an ordinary mortice lock the bolt slides horizontally out of the lock case. The further the bolt has to engage in the keep, the deeper the lock case needs to be. In aluminium and steel doors the stile is often too narrow for a sturdy mortice lock. A narrow stile lock with a swing bolt solves this: because the bolt pivots, it can still reach far enough into the keep while the lock case stays narrow.
Types of bolt
- Straight swing bolt: a flat bolt that swings out, for ordinary hinged doors.
- Hook bolt: the bolt is hook-shaped and catches behind the keep in the frame. This type is designed for sliding doors: an ordinary bolt could slide sideways out of the keep, a hook cannot.
What to look for
- Match the system: the lock must suit the door’s profile system, including the correct backset (distance from forend to centre of the cylinder). Order by type and size of the existing cut-out.
- Keep and frame: the bolt must be able to swing fully into the keep. A badly adjusted door or distorted frame causes sticking.
- Security: for an external door the cylinder and furniture matter too. A good lock with a projecting cylinder remains a weak point.
- Multipoint locking: on tall doors or where security demands are higher, the lock is often combined with extra locking points.
Related terms
- Lock bolt
- Multipoint lock
- Sliding door
- Mortice latch
- Lock centres
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