Locksmith Dictionary - Letters Q - T

Locksmith Dictionary: U - Z

Locksmith Dictionary: M - P

R (back to top)

rack bolt A bolt, usually a door bolt, which is toothed so that it may be operated by a pinion.
radiused forend A lock forend which is shaped radically, for use on one of a pair of swing doors.
rebate The measurement of the stepped reduction or recess in theforend of a rebated lock.
rebated (lock or latch) A morticelock or latch with a forend specially shaped to correspond with the shaped meeting edge of the door for which it is intended. See "Full Rebated".
release A striker in Various forms to replace the lock strike and is operated electronically.
relocker A locking mechanism independent of any key operations, mounted remotely within a safe mechanism so as to relock the boltwork under certain forced attacks.
repeat differs That supply of differs which have been issued previously. This is usually associated with master keyed suites and where a replacement lock is required to have the same differ as the original.
reversed bolt (RB) A springbolt which has been turned round in its case to suit a door opening outwards instead of inwards. Great care should be taken to use this term RB only when ordering items which are required with the springbolt reversed.
rigid grilles Heavy duty, welded construction, rod or bar grilles, usually fitted externally or internally to the fabric of a building.
rim cylinder This relates to a pack which usually comprises the cylinder with plug, rose, connecting bar, two connecting screws and two keys.
rim lock A lock or latch typically mounted on the surface of a door or drawer.
roller bolt A springbolt made in the form of a roller, instead of being bevelled. It is recommended far more silent and easier closing of a door.
rose (1. A cylinder rose or ring in cylinder locks or latches.
(2. In door furniture, it is the small plate to which the lever handle or knob is affixed and which is screwed to the door surface.

S (back to top)

safe lock A general term for the many varieties of key operated and other locks for safes.
sash lock An upright mortice lock, consisting of a latch bolt and a key operated bolt.
sash ward Used in rim and mortic elocks, alone or in conjunction with levels for the purpose of obtaining or increasing the differs.
servant key The change key of one (or more than one if of the same change) lock in a master keyed or grand master keyed suite.
set screw One which tightens or fastens another part after assembly or adjustment.
scotch spring lock A two-bolt rim lock with the reversible springbolt above or below the horizontal plane of the follower.
shackle The part of a padlock which passes through an opening in an object or fits around an object and is ultimately locked into the case.
shank(of key) The part of a pin or pipe key between the bow and the end, excluding the blade.
shear line The dividing line between the plug and the shell (the height to which the tops of the lower pins must be raised to open the lock).
shell The outer part of the lock that surrounds the plug.
shoot (of bolt) The distance a springbolt moves under the action of its spring.
shoulder(or bow stop) The edge of the key that touches the face of the lock to define how far the key is inserted into the lock.
side bar This is in addition to the existing pin or disc mechanism, and is a bar usually along the length of the mechanism and does not allow rotation until the mechanism is correctly lifted and can be directly controlled by the key.
side wards Notches cut into the sides of bitted keys so fashioned to enable the key to turn.
single-acting lever tumbler A lever tumbler which must be moved a minimum distance to allow travel of a bolt, but cannot be moved so far as to restrict travel of the bolt.
skeleton key Any non-cylinder key whose bit, blade, and/or post is cut away enough to allow it to enter and turn in locks with different ward arrangements. There is no universal skeleton key. Skeleton keys cannot be made for lever and cylinder lock mechanisms.
sliding grilles Steel sliding grille gates in single or double leaf, running on top and bottom guide tracks, locked by padlock or integral lock.
sliding lever A Lever which slides between or on guides instead of swinging on a pivot.
spacer A distance piece of thin metal placed between the levers of some locks.
spacing The term used to describe the horizontal distances across a key blade or bit.
spindle That part of the door furniture usually of square section which passes through the follower hole and is fitted to the knob(s) or lever handle(s) to operate the springbolt.
spiral spring A spring made of wire to approximately V shape like a feather spring; with one or more coils formed at the apex of the V to fit over a stump in the lock case.
spool pin A pin that has a groove cut around it's periphery. The groove is intended to catch at the shear line as a deterrent to picking.
spoon The flattened end of a padlock shackle containing the bolt hole or slot which the bolt enters.
spring-loaded Moved under the control of, or against the pull of, a spring fixed at one end.
spring shackle padlock A padlock, the shackle of which springs open when unlocked, and is locked by snapping to.
springbolt Sometimes called the latchbolt. A bolt having the outer edge shaped by bevelling of the vertical face. It is a bolt which may be pushed back into the lock-case and will return to the extended position without mechanical assistance.
springlatch A latch with one bevelled springbolt which locks the door when shut. It is opened by key from the outside and by knob from inside.
steel lining Steel sheet linings applied to external or both faces of a door, usually screwed and bolted through.
stile A vertical member of a door.
stop knob (snib) A device incorporated in some latches and locking latches to hold the bolt retracted or deadlock the bolt when door is closed.
stop button(s) There are generally two in number. They are incorporated in the forend of certain cylinder mortice nightlatches or locks. One button, when depressed, renders the outside furniture inoperable and the other, when depressed, restores the power of operation. They are useful for privacy and on vestibule doors. They are sometimes referred to as "stopworks".
straight cabinet lock A cabinet lock, with no flange on the case, for flush fitting to cupboards and drawers.
striking plate Sometimes referred to as a "striker". It is a shaped flat metal plate fixed to the door frame or jamb with one or more bolt holes into which the bait or bolts shoot. There is a shaped projecting lip on one side to guide the springbolt., It is used with all mortice locks or latches, and with rim locks or latches with reversed springbalt on an outward opening door.
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 locks and/or locking latches and padlocks of different types and changes incorporated together under a master key or grand master key.

T (back to top)

talon The gap that is formed by two curves to the radius of the bolt step of the key in a deadbolt lathe or runner of a lever lock where the key engages the bolt.
throw The distance a deadbolt moves under the action of its key.
thumb turn A small fitting, on the inside of a mortice lock, which is gripped between thumb and finger to operate the deadbolt. It should not be used on glass-or wood-panelled doors.
till lock A drawer lock, or more correctly a cabinet lock, having a springbolt that shoots upwards and a vertical keyhole. It is self-closing and is unlocked by key.
time lock A clockwork or electric timing device which disallows operation of a lock or the opening of a door on safes or strongrooms.
tip The very end of part of the key that you stick into the lock first.
toe (of a shackle) That part of the shackle which may be removed from the padlock body.
top master key The highest level masterkey that fits all the locks in a multi-level masterkeyed system.
top pins The pins in a lock that sit on top of the pin stack.
tubular key cylinder A cylinder whose tumblers are arranged in a circle and which is operated by a tubular key.
tubular lockset A bored lockset whose latch or bolt locking mechanism is contained in the component installed into the edge bore.
tumbler A movable detainer which must be lifted before the bolt of a lock can move.