As with any profession there is a whole lot of technical jargon a locksmith’s world that will confuse the uninitiated. Whilst our locksmith will always do his best to explain any relevant terms to a customer this quick guide will let you in on some of the main terms we use.
- Anti-thrust bolt
- A spring bolt which cannot be pushed back when the door has been shut unless by the use of a key.
- Astragal
- A moulding to cover the gap between a pair of meeting doors.
- Backplate
- The mounting plate which is attached to the door to allow a nightlatch to be attached to.
- Bit
- The part of the key which is cut to shape to match the leavers (mortice lock) or pins (cylinder) which differentiates one key and lock from another.
- Blank Key
- A key that will fit in a keyhole but the blade has not been cut to operate the lock.
- Bolt
- The part of a lock which fastens the door by protruding from the lock case to engage in keep or strike plate.
- Bow of a key
- The part of a key that is held in the fingers when used to open a lock.
- BS 3621
- The “current” standard specification for door locks. This kind of lock has to have the ability to be dead locked and the key taken away from both sides so no one can gain access or exit the door without a key. The lock case has to also have certain criteria to be awarded this standard.
- Cabinet Lock
- A generic term for all locks use on furniture such as cupboards, drawers, chests etc.
- Casement Door
- A hinged door or pair of doors and often called French windows that are mostly glass.
- Closed Shackle Padlock
- A padlock with the minimum amount of shackle visible when locked. This improves security against forcing or use of bolt-cutters.
- Cylinder
- Part of a lock with inner co-axial plug which houses the pins, drivers, or disc tumblers and springs in the cylinder body.
- Cylinder Rose
- The metal disc which surrounds the outer face of the cylinder standing slightly proud of the outside of a door.
- Deadlock
- A lock having only a deadbolt operable from one or both sides by key. A single-entry deadlock is opened by a keyhole only on the outside.
- Differs
- Short for “different combinations” or changes of key combinations. i.e. 1 key differs from any other.
- Double Locking
- Where the latch of a nightlatch is thrown into the frame keep due to its internal operation, thus adding additional security in the form of more latch in the frame .
- Forend
- The part of a lock or latch through which the bolt protrudes. Also referred to as the face plate.
- Furniture
- Items fitted to the door including handles and plates, door knockers, letterboxes.
- Hasp and Staple
- The two pieces of the fixing for a door or box to be secured by a padlock. The hinged part is called the hasp which is fitted to the door or lid of a box and shuts over the staple, which is on the frame or the body of the box. You should always use a hasp and staple where the heads of the fixing screws are completely covered when the padlock is locked in position.
- Jamb
- The vertical part of a door or window frame. The top rail of a door frame is sometimes referred to as the top jamb.
- Levers
- The mechanism in a lock with one or more levers which have to be moved by a key to operate the lock. the lever is cut away to provide various key combinations.
- Master Key
- A key which will open every lock in set of master keyed locks.
- Multipoint Locking Mechanism
- A type of lock fitted with a minimum of two or more locking points such as bolts / hooks / wedges between the door and the frame interlinked and centrally controlled by means of a single action either lifting a handle or turning a key turn. Most commonly found in Upvc doors and some composite wooden doors.
- Nightlatch
- A type of lock fitted to the inside of a wooden door most commonly with a bevelled spring latch which shoots across to latch the door when closed. The bolt can be withdrawn by key from outside and by knob or lever on the inside. Most commonly but incorrectly called “A Yale Lock”
- Pin Tumbler Mechanism
- The mechanism in the cylinder or body of a cylinder pin tumbler lock. When the correct key lines up the pins and drivers the plug in the cylinder can rotate and the lock will open.
- Plug
- The part of the pin-tumbler cylinder mechanism or disc tumbler cylinder mechanism into which the key goes into and turns to operate the lock.
- Rim Cylinder
- A pack which normally comprises of a cylinder with plug, rose, connecting bar, two connecting screws and two keys and fits into a “Nightlatch”.
- Spindle
- The long square rod that passes from one handle through the door via the “lock” follower to the other handle or knob to operate the door latch.
- Striking Plate
- Sometimes called a striker or keep. A shaped flat metal plate fixed to the door frame or jamb with one or more bolt holes into which the bolt or bolts shoot.
- Wards
- An old style and little used form of fixed obstructions inside a lock case to stop the use of the wrong key. The correct key is cut to pass over the wards and operate the lock. Generally only used on cheap 2 and 3 lever lock cases.
