Locksmith Lingo
Rim lock : Fits on the face of the door, rather than being set into the body of the door itself.
Keyed Alike : Where many locks share the same key, inexpensive and practical to have one key fit all..
Mortice lock : A lock set into the body of the door, in a prepared hole that woodworkers call a mortice.
Latch : A bolt that is sprung ("live") and with a bevel on one face; so the door can be latched shut simply by pulling it to.
Bitting : Is the part of the key that actually engages the tumblers to activate the lock. This is so you can unlock or lock the door.
Deadbolt : A rectangular section bolt that can only be disengaged with a key or thumb turn; unlike a live latch, a dead bolt is not sprung and cannot be pushed back.
Hook bolt : (or claw bolt) Necessary for sliding doors; also found on hinged doors where they make it more difficult to force the door and frame apart.
Cylinder lock : There are pins, usually 5 or 6 but can be 10 or more, that stop a cylinder from turning; the key lifts the pins.
Euro profile : A cylinder lock mechanism utilising a cam actuator; used in a mortice lock, the lock's cylinder can easily be replaced without replacing the whole lock; inside and outside can both be key-operated or the inside can be provided with a thumb turn.
Shear Line : In lock picking a cylinder lock, the shear line, also known as the split line in Australia, is where the inner cylinder ends and the outer cylinder begins.
Lever lock : Levers (more substantial than pins) stop a bolt retracting; the key lifts the levers Very often, but not always, a cylinder lock operates a latch rimlock (or night-latch); and a lever lock operates a mortice deadbolt.
Automatic deadbolt : As the door closes, a deadbolt automatically engages.
Automatic deadlatch : When the door has closed and latched, the latch cannot be retracted, for example with a credit card.
Raking technique : A method of lock-picking in which the individual attempting to pick a lock inserts a pick all the way into the lock, and then rapidly withdraws it. This in effect "rakes" the pins, and hopefully places a few of the top pins on the sheer line, or opens the lock. With most types of locks this method has been made ineffective by change in design.
Strike : The box that the bolt enters in the door jamb.
Striking plate : The plate on the strike upon which the latch strikes and operates.
Snib : A knob to hold the bolt retracted or deadlock it.
Differs : The number of different key patterns for a lock.
Wards : These are the obstructions that give a lever lock keyway a non-rectangular section thus requiring a key with matching section; there can be wards on the back plate of the lock requiring matching cutouts on the leading face of the key; on very old, and on cheap, two-and three-lever locks, this is part of the, limited, protection.
Skeleton keys : Keys thin enough and flexible enough that they can get past the wards.
Butts : The traditional term for hinges.
BS3621 : An insurance standard for locks, specifying, for example, the minimum number of differs, that there is protection against drilling and sawing, and that the strike box is metal (equivalent to the European standard EN12209).
E : European - As in the difference between, for example, a Chubb 114 and a Chubb 114 E , where the European standard (and now BS3621:2004) asks for a bolt that throws (extends) 20mm, rather than the 14mm throw required by BS3621:1998.
Rack bolt : A bolt with teeth along is length, that is operated from the inside only, and is extended by turning a toothed key.
Barrel bolt : The common-or-garden cylindrical shoot bolt that has a knob for hand operation.
London bar : Because a rim lock isn't set into the door and frame, it's vulnerable to a kick; a London bar fits over the strike box (or staple, or keep) and better secures it to the frame.
Birmingham bar : Like a London bar, but simply a straight bar to reinforce the frame; attached with non-returning screws if fitted to the outside.
Hinge bolts : Short bolts that engage the door into the frame on the hinge side as it closes, increasing resistance to forced entry and countering attacks to the hinges if they are visible from outside.
Escutcheon : Plate fitted around keyholes and handle spindles to hide the holes in the wood, stop the key marking the wood and perhaps to strengthen.
Lock reinforcing plate : Cutting a mortice into a door in order to fit a mortice lock weakens the door; when a door isn't substantial enough to take this, a reinforcing plate, bolted to the door around the lock area, can compensate and resist kicking attacks.
Sash : A puzzlingly overused term: the word is basically just another word for frame.
Sash window : Sliding windows, usually vertically, usually in pairs; would be more accurately described as a double-hung window where each window has its own sash.
Sash lock : On a window, it locks a sash in place; on a door (and another puzzle), it has come to mean a lock combining a handle-operated latch and a key-operated deadbolt in one mortised lock.
There is yet another puzzle here. Why did sash windows become popular in the UK? They seem to have almost no redeeming features compared with, say, casement windows; and are found almost nowhere else.
Casement window : A window where the sash is hinged rather than sliding.
Muntin : A strip that separates panes in a sash.
Mullion : A vertical separator dividing a window or other opening.
Pane : A piece of glass in a window.
Light : An opening in a window.
Fanlight : A semi-circular pane, usually at the top of a window or a door.
Transom : A window above a door, or the horizontal strip between panes in a window, or between window and door.
