Glossary - Locksmith Industry Definitions
A high security cylinder is protected or ‘armoured’ against drill attack using hardened pins and plates.
A small auxiliary bolt next to the main bolt hits the striking plate or staple and is pushed in every time the door is closed. This action automatically holds the main bolt in the locked position.
An additional bolt which is activated by the strike when the door is closed, automatically deadlocks the latch bolt against end pressure.
The plate, fixed on a door, to which the moving parts of a lock or latch are attached.
The feature of a door closer unit that prevents shock and possible damage when the door is forcibly opened.
The horizontal distance from the edge of the door to the central line of the cylinder key hole.
A lock with latch bolt operable on both sides by furniture and deadbolt operated from inside only; usually by thumb turn.
Bit (of key) or key bit
That part of a key which is specially shaped or notched to operate the mechanism of its own particular lock or latch.
The shaping or notching of a key blank to transform it into a key to operate its own lock or latch.
Blade (of key)
That part of a cylinder or lever key which is to be or has been notched.
Blank (key) or key blank
A partly made key, which has been shaped to enter the keyhole of a certain type of lock or latch, but of which the blade has not been finally notched to operate any individual lock.
The part of a lock or latch which provides the fastening or engagement by protruding from the case or for end to engage in the staple or striking plate.
Bow (of key)
That part of the key which is held in the fingers when operating the lock or latch.
A strike in which the bolt recess is enclosed or boxed, thus covering the opening in the jamb.
A generic term to include all locks of any type for use on pieces of furniture, such as cupboards, drawers, chests, boxes and the like.
Usually a tongue fixed to the end of the plug of a cylinder lock or latch.
That part of a lock or latch containing the mechanism.
A window with a sash hung about a vertical axis by hinges at the side.
Center hook bolt
On Chubb multipoint locks - used to grip the door sash and frame together facilitate compression.
The key which opens one particular lock. Usually a term used with Master-Keyed Suites.
A type of deadbolt having claws which swing outside when the bolt is shot. Such locks are usually fixed to sliding doors.
Close shackle padlock
A padlock the body of which is built up so that the minimum amount of shackle is visible when locked. Improved security against forcing or use of bolt-croppers.
Once fitted the fixings of the lock or security device are hidden from view.
The thin metal strip fitted to the rear of the cylinder plug which operates the spring bolt in a cylinder rim lock. It passes through the thickness of the door, and is usually indented at intervals to ease shortening to the correct length.
The two screws which fix the cylinder body to the mounting plate.
Systems used to allow contractors to gain entry to a building during construction but to prevent entry by the same contractors after the building has been occupied or handed over.
The mechanism that operates the lock.
A key, having a bow and long blade in which V cuts are made along the upper edge to operate the pins and drivers in a pin tumbler mechanism.
Cylinder mortise lock
A mortise style lock operated by either a euro or oval cylinder. Most commonly used in master key systems. Available as either a deadlock or sash lock (door lock).
Clutch head screws
See one-way screws.
A shaped metal disc which surrounds the outer face of the cylinder of a cylinder mechanism assembly. Usually stands slightly proud of the outside face of the door.
A bolt which is not activated by a spring. When locked the bolt cannot be returned by end pressure.
A nightlatch or latch, the spring bolt of which can be locked (or deadlocked) by key or other means.
A single bolt mortise lock which can be used to supplement a standard cylinder rim lock on the front door.
On cylinder rim locks with this function, once you have left the house and closed the door, insert the key in the cylinder and give it an anti-clockwise turn. This deadlocks the bolt preventing it from being pushed back.
A feature of a door closer which holds the door in the open position for a number of seconds before the closing action commences. This feature is ideal for use by the handicapped, the aged and people with prams, trolleys etc.
An abbreviation of “different combinations” (see key combinations).
The small shaped discs (usually of metal) in the disc tumbler mechanism which are the means of providing different combinations.
Disc tumbler locks
A cylinder lock having discs instead of pin tumblers.
The manual means by which the latchbolt on a cylinder rim lock is deadlocked. Insert the key in the outside cylinder and give it a reverse turn. The inside handle is now locked and unopenable until the key is reinserted into the outside cylinder. Prevents unauthorized entry by someone breaking adjacent glass, reaching in and turning the handle.
Double throw latchbolt
On Chubb multipoint locks - an extra key turn projects the latch a further 6mm and secures it.
Locks and cylinders can be protected against drill attack by utilizing hardened steel plates and pins.
Usually the upper of each pair of pin tumblers in the cylinder mechanism. The lower are known as pins.
A non-operating door trim which is installed for appearance or as a door pull only.
A lock is designed so that only light spring pressure is required to move the bolt.
An electrical device that replaced a regular lock strike to enable a door to be released by remote control.
A key supplied with Hotel locks. These locks have a feature which, when applied, prevents entry by normal service keys, master keys or grand master keys. At all times entry can be gained by the emergency key which suits that group of locks.
The cover for the keyhole of a mortise or similar lock. (Also known as rose).
The security device which operates a euro profile cylinder mortise lock. Supplied as either single, double or single with thumb turn operation.
A strip of metal fixed to the outer edge of a mortise lock which fits flush with the door edge.
Final exit door
The exit door through which entry must later be obtained, and so cannot be bolted. Usually the front entrance door. N.B. - As one must rely on the lock only for security, it is very important that a high security lock should always be fitted to a final exit door.
That part of the lock mechanism containing a square hole to admit the spindle (to which door handles are attached) which pulls back the spring bolt when turned.
Cylinder rim locks which have an automatic deadlocking feature are protected against jimmy attack because the bolt is held in the locked position every time the door is closed. High security cylinder rim locks also have an extended striking plate giving a stronger fixing to the frame and so are resistant to an attempt to kick the door open. High security mortise locks have a box striking plate too.
That part of the lock or latch through which the bolt(s) protrude, and by which the lock or latch is fixed to the door.
Furniture (door handles)
The additional items needed, which are screwed to one or both sides of the door to enable a lock or latch to be manually operated.
Grand master key
A key within a system that operates all locks in a number of separate groups which have their own master keys.
For some locks (usually specialized locks for use in the commercial sector) the handing of the door to which the lock is fitted must be specified when ordering.
Hasp & staple
A fastening in two pieces to be secured by a padlock. (Also known as a pad bar).
The feature of a door closer unit which enables a door to be held in the opened position until released.
A snib, button or other device which can hold the bolt in the retracted position.
A lock with a hook shaped bolt. Such locks or latches are usually fixed on UPVC or sliding doors.
A mortise or rim lock having the follower hole further from the forend than the keyhole, and in the same horizontal plane.
The vertical part of a door or window frame. In some areas the top rail of a door frame is referred to as the top jamb.
A term sometimes used for a staple or striking plate.
A small removable device for operating the mechanism of its own lock.
A partly made key, which has been shaped to enter the keyhole of a certain type of lock or latch, but of which the blade has not been fully shaped to operate the mechanism of the lock.
A term sometimes used instead of “differ”. The change or differ of the key is generally indicated by numbers and sometimes numbers and letters marked on the bow.
This is the number of possible key combinations before the same key is repeated.
The hole into which the key enters to operate the lock or latch. Often referred as the keyway, particularly in a cylinder mechanism.
Used in conjunction with an electric strike to provide an easy means of Access Control. Most common keypads require a four digit combination to be entered.
The type of product with one bolt only, the beveled spring bolt or roller bolt, to latch or fasten the door, but not capable of being locked.
A bolt having a beveled edge. (Also see spring bolt).
The traditional method by which a mortise lock is operated; 5, 3 or 2 lever mechanisms. The cutting on the key raises the levers until they form a horizontal plane. The deadbolt can then be thrown into the locked position.
Door furniture for use as an alternative to a knob for operating the latch of a lock. Lever handles can be spring loaded or non-spring loaded. Spring loading ensures the handle returns to the horizontal position after use. Non-spring loaded handles rely on the springing in the lock.
Door handle used in conjunction with Chubb multipoint locks.
A lock mechanism having, as its principal feature, one or more levers.
Door handle used in conjunction with Chubb multipoint locks.
Lip (of striking plate)
The projection on one side of a striking plate on the surface of which the spring bolt of the lock or latch first strikes when the door is closed. Usually radiuses or beveled to guide the spring bolt.
A device operated usually, but not always, by a key, having one or more bolts or other parts to fasten and secure a door, lid, drawer or other parts.
A lock complete with necessary furniture including a spindle, ready for fixing to the door.
Long shackle padlock
A padlock shackle with a greater amount of clearance than the standard shackle.
Applied to the cylinder mechanism to ensure smooth operation. Chubb recommend regular use of WD40 on moving parts, otherwise a graphite powder for the cylinder plugs.
A key which will open a series of locks in a Master Keyed Suite.
A lock or latch capable of being operated also by a Master Key as well as its own change or servant key.
Mechanism (of locks or latches)
The arrangement of the component parts and the manner in which they perform to achieve the required security and differing when operated by its key.
A hole cut into the thickness of one edge of a door to receive a mortise lock or latch.
A lock designed to be recessed into the edge of a door, rather than being mounted to its surface.
Mortise night latch
A hybrid between a mortise lock and a cylinder rim lock/night latch. The automatic deadlocking function by means of a small auxiliary bolt ensures that every time the door is closed it is locked. Ideal for flat entrance doors.
High security locking mechanism for doors that offers a range of ‘locking points’ often incorporating hooks, rollers, mushrooms and deadbolts.
A driver in the cylinder mechanism which has a mushroom shaped head. These provide a very effective anti-pick element against being lifted by a lock-pick or similar.
Narrow case lock or latch
A rim lock or latch the case of which is made specially narrow, usually less than 75mm wide, for fixing to the narrow stile of a paneled or flush door.
A rim or mortise latch with a beveled spring bolt or roller bolt which shoots when the door is closed, but can be withdrawn by key from outside and by knob or lever handle from inside. Usually provided with a stop knob, slide or snib to hold the bolt retracted and to deadlock the bolt when shot in the closed position, even against the action of the key.
One-way screws (or clutch head screws)
Screws with specially shaped heads to prevent removal by conventional screwdrivers.
The security device which operates an oval profile cylinder mortise lock. Supplied as either single, double or single with thumb turn operation.
A latch set with knobs or levers on both sides of a door but no locking function.
Passing (or to pass)
Any key which operates a lock is said to pass the lock. If locks are made “alike change” one key will pass all the locks.
Pin tumbler mechanism
The mechanism incorporated in a Cylinder Rim Lock or Padlock. The cylinder houses the pins and drivers under spring pressure. The correct key lines up the plug and cylinder, thus allowing the plug to rotate and the lock to be operated.
Usually the lower of each pair of tumblers in the cylinder mechanism. The upper are known as drivers.
The part of the pin-tumbler cylinder mechanism into which the key enters and which the key turns. It houses the pins of a pin tumbler cylinder mechanism.
A lock used on bathroom and bedroom doors having an inside button or turn knob to lock the knob or lever with an emergency function which will unlock the set from the outside.
High security patented cylinder system. Operates on 7 pins and has achieved CEN 5.
The stepped shaped reduction or recess cut along the meeting edges of each of a pair of swing doors leaving projections which overlap when the two doors stop on each other at closing.
Rebated (lock or latch)
A mortise lock or latch with a forend specially shaped to correspond with the shaped meeting edge of the door for which it is intended.
Used on overlapping double doors or single doors closing into the frame. The rebate raises the height of the edge of the door to allow the mortise lock to be fitted flush.
Otherwise referred to as a block lock. Usually used on roller shutters or double gates.
The supply of differs which have been issued previously. Usually associated with Master Keyed suites and where a replacement lock is required to have the same differ as the original.
Reversible latch bolt
On mortise door locks (sash locks) the latch bolt has a beveled edge. This edge hits the striking plate and closes the door. Depending on whether the door is hinged on the right or left determines which way the beveled edge of the bolt needs to face. On all Chubb mortise locks the latch bolt can be reversed.
A cylinder which connects to a rim lock through the door, allowing external operation.
Rim lock, Rim latch
A lock or latch which is mounted to the surface of a door, rather than inserted into the edge of a door.
A spring bolt made in the form of a roller, instead of being beveled.
On Chubb multipoint locks, stainless steel rollers are available providing a tight weather seal for doors.
Rose (or ring)
A shaped metal disc which surrounds the outer face of the cylinder.
Used when the mortise for a forend is cut out using automated machinery.
A 2 bolt mortise lock used in conjunction with door handles which operate the latch bolt. Commonly referred to as a door lock.
A 2 piece window comprising of top and bottom sections which move independently of each other.
The change key of one (or more than one if of the same change) lock in a Master Keyed or Grand Master Keyed Suite.
The looped metal locking section of the padlock.
Shoot (of bolt)
The distance a spring bolt moves under the action of its spring.
On Yale multipoint locks - a sintered steel bolt optional extra to secure the head and sill of the door into the frame.
The snib is the mechanism by which the bolt can be held back, (put ‘on the latch’). It can either be a button with slide movement, or a push movement.
The part of the door handle usually of square section which passes through the top whole follower in a mortise door lock to operate the spring bolt.
Sprung shackle padlock
A padlock, the shackle of which springs open when unlocked, and is locked by snapping to.
Sometimes called the latch bolt. A bolt having the outer edge shaped by beveling of the vertical face. A bolt which may be pushed back into the lock-case and will return to the extended position without mechanical assistance.
Stainless steel faceplate
On Yale multipoint locks - the exterior plate to fix the lock in situ within the door.
1. A box-like fitting on the jam of an inward opening door, and into which the bolt or bolts of a rim latch or lock shoot when door is closed.
2. Part of the hasp and staple for use with a padlock. The padlock shackle passes through the eye or hole in the staple.
Also referred to as door frame. Commonly there is a standard stile or narrow stile.
A device fixed in or on a door jamb into which the lock or latch bolt engages when the door is closed.
Sub grand master key
A key which will operate all locks in its own main group or (sub-grand suite) of a Grand Master Keyed system.
Sub master key
A key which will operate all locks in its own smaller group (or sub-suite) of a Grand Master Keyed system.
Suite (of locks)
A group or collection of locks and/or locking latches and padlocks of different types and changes incorporated together under a Master Key or Grand Master Key.
The distance a deadbolt extends from the case under the actions of its key.
A small fitting on the cylinder found on the inside of a door which is gripped between thumb and finger to operate the deadbolt. Should not be used on glass or wood-paneled doors. Ideal for fire exit doors where escape is always needed.
Commonly referred to as door furniture.
Tubular mortise lock
One having a tubular shaped case and requiring bored (round) holes rather than a chiselled rectangular mortise.
A component of a lock or cylinder which prevents operation of the lock mechanism except by insertion of the correct key.