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Active Door (in a pair of doors):

The leaf that opens first and the one to which the lock is


Anti-Friction Bearing: Any bearing

having the capability of effectively reducing friction.

Anti-Friction Latch Bolt: A latch

bolt designed to reduce friction when the bolt starts to engage

the lock strike.

Architectural Hardware: Term applied

to all hardware used in building construction but particularly

that used on or in connection with doors, windows, cabinets

and other movable members.

Armored Front: A lock that consists

of two plates: one, the under plate, is fastened to the case

and is unfinished; two, the finish plate, is fastened to the

under plate and when in place covers the cylinder set screws

thus protecting them from tampering. Used on mortise locks.

Armor Plate: A plate similar to a

kick plate but covering the door to a greater height, usually

40″ (1040 mm) or more from the bottom.

Astragal: A molding or strip whose

purpose is to cover or close the gap between the edges of

a pair of doors. Some types overlap, others meet at the center

line of the gap. (See Coordinator.)

Auxiliary Dead Latch: A supplementary

latch that automatically deadlocks the main latch bolt when

the door is closed. (Also called Deadlocking Latch Bolt.)

Back Check: Optional feature in hydraulic

door closers slowing the opening swing of door somewhere between

60 and 85 degrees of opening. Designed to protect an object

be hind the door. Not intended to act as an overhead stop.

Backset (of a lock): The horizontal

distance from the face of the lock to the center line of knob

hub, keyhole or cylinder. (Measured from the high side of

a beveled door.)

Backset (of a hinge): The distance

from the edge of the door to the hinge.

Ball-Bearing Hinge: A hinge equipped

with ball bearings between the hinge knuckles to reduce friction

(See Anti-Friction Bearing.)

Bevel (of a door): The angle of the

lock edge in relation to the face of the lock stile. Standard

bevel is 1/8″ in 2″ (3.2 mm in 50.8 mm). If otherwise

detailed it must be so noted in ordering locks.

Bevel (of a lock front): The angle

of a lock front when not at right angle to the lock case,

allowing the front to be applied flush with the edge of a

beveled door

Bit (of a key): The projecting blade,

cut in a manner that actuates the tumblers and permits the

lock bolts to be operated.

Bored Lock (or Latch): Lock or latch

whose parts are intended for installation in holes bored in

a door

Box Strike: A strike that also provides

a complete housing to protect the bolt openings.

Builders Hardware: See Architectural


Butt (Hinge): A type of hinge designed

for mortising into the edge of the door and into the rabbet

of a door frame.

Cam (of a cylinder): A rotating piece

attached to the end of the cylinder plug to engage the locking


Cane Bolt: A heavy cane-shaped bolt

with the top bent at right angles; used on the bottom of doors.

Case (of a lock): The box containing

the lock mechanism.

Chain Bolt: A spring bolt actuated

by a chain attached to the spring bolt for application at

the top of the door.

Chain Door Fastener: A device that

limits the opening of a door by means of a chain.

Changes (Key): The different bittings

or tumbler arrangements in a series of locks.

Checking Floor Hinge: A device placed

in the floor that combines top and bottom pivots for hanging

the door with a controlled speed dosing mechanism.

Continuous Hinge (also called Roton Hinge):

A hinge designed to be the same length as the moving part

to which it is applied.

Coordinator: A device used on a pair

of doors to ensure that the inactive leaf is permitted to

close before the active leaf. Necessary when an overlapping

astragal is present and exit devices, automatic or self latching

bolts are used with closers on both door leaves.

Cup Escutcheon: A door plate, for

use on sliding doors, having a recessed panel to afford finger

hold and to contain a flush ring and sometimes a cylinder,

all being flush with the surface of the plate.

Cylinder (of a lock): The cylindrical-shaped

assembly containing the tumbler mechanism and the keyway,

which can be actuated only by the correct keys.

Cylinder Collar: A plate or ring used

under the head of a cylinder.

Cylinder Lock: A lock in which the

locking mechanism is controlled by a cylinder.

Cylindrical (locks and latches): A

term used to describe bored locks, which have a cylindrical

case into which a separate latch bolt case fits.

Cylinder Screw: The set screw that

holds a cylinder in place by preventing the cylinder from

being turned after installation.

Deadbolt (of a lock): A lock bolt

having no spring action nor bevel, and which is operated by

a key or a turn piece.

Deadlock: A lock equipped with a dead

bolt only.

Deadlocking Latch Bolt: A latch bolt

incorporating a plunger that is held in a retracted position

when a door is dosed, thus preventing the bolt from being

retracted by end pressure.

Dogging Device: As used in exit devices,

a mechanism that fastens the cross bar in the fully depressed

position, and also retains the latch bolt or bolts in a retracted

position, thus permitting free operation of the door from

either side.

Door Bolt: A manually operated rod

or bar attached to a door providing means of locking.

Door Closer Bracket: A device whereby

a door closer may be installed on the frame rather than directly

on the door.

Door Closer or Check: A device combining

a spring for closing and a compression chamber into which

the liquid or air escapes slowly, thus providing a means of

controlling the speed of the closing action.

Door Holder: A device that holds a

door open at selected positions.

Door Pivot: A hinging device embodying

a fixed pin and a single joint. Most types include lateral


Door Stop: A device to stop the swing

or movement of a door at a certain point. Also an architectural

term defining that part of a door frame against which the

door closes.

Double-Throw Bolt: A bolt that can

be projected beyond its first position into a second, or fully

extended one, thus providing extra security.

Drivers: The upper set of pins in

a pin tumbler cylinder, which, activated by the springs, project

into the plug until raised by insertion of the key.

Drop Escutcheon (or Key Plate): One

having a pivoted plate that covers the key hole.

Drop Ring: A ring handle attached

to a spindle that operates a lock or latch. The ring is pivoted

but remains in a dropped position when not in use.

Dummy Cylinder: A mock cylinder without

any operating mechanism for use where effect is desired.

Dummy Trim: Trim only, without lock;

usually used on the inactive door in a pair of doors.

Dust-Proof Strike: A strike with a

spring plunger that completely fills the bolt hole when the

bolt is not projected.

Dutch Door Bolt: Device for locking

together the upper and the lower leaves of a Dutch door.

Edge Plate: An angle or channel-shaped

guard used to protect the edge of a door.

Edge Pull: A pull mortised into the

edge of a sliding door.

Electric Strike: An electrical device

that permits releasing of the door from a remote control.

Escutcheon (Elongated): A plate long

enough to span a lock case and having holes for knob bushing,

bit key, cylinder, turn knob and similar operating members

as required.

Escutcheon (Key): See Key Plate.

Exit Device: A door-locking device

designed to grant instant exit by pressing on a cross bar

that releases the locking bolt or latch.

Extension Flush Bolt: A flush bolt

in which the connection between bolt head and operating mechanism

is by means of a rod inserted through a hole bored in the

thickness of the door.

Extension Link: A device used to provide

long backsets in bored locks.

Face (of a lock): The exposed surface

that shows in the edge of a door after installation. (See


Fast Pin Hinge: One in which the pin

is fastened permanently in place.

Finish Builders Hardware: Hardware

that has a finished appearance as well as a functional purpose

and that may be considered a part of the decorative treatment

of a room or building. Also termed Architectural Hardware,

Finish Hardware and Builders Finish Hardware.

Fire Exit Bolt: See Exit Device.

Floor Closer: A closing device installed

in the floor under a door.

Floor Hinge: A combined pivot hinge

and closing device set either in the floor or in the bottom

of the door. It may be spring type only or may be combined

with liquid control.

Flush Bolt: A door bolt so designed

that when applied it is flush with the face or edge of the


Flush Cup Pull: A pull mortised flush

into a door, having a ring pull that folds flat into the cup

of the pull.

Flush Ring: A flush door pull mortised

in a door, having a ring pull that folds flat into the cup

of the pull.

Foot Bolt: A type of bolt applied

at the bottom of a door and arranged for foot operation. Generally

the bolt head is held up by a spring when the door is unbolted.

Friction Catch: Any catch which when

it engages a strike is held in the engaged position by friction.

Friction Hinge: A hinge designed to

hang a door and hold it at any desired degree of opening by

means of friction control incorporated in the knuckle of the


Front (of a lock): The plate through

which the latching or locking bolts project. (See Face.)

Grand Master Key: A key that operates

locks in several groups, each of which has its own master


Guard Bar: A series of two or more

cross bars generally fastened to a common back plate to insure

protection of glass or screen in a door.

Hand (of a lock, etc.): A term used

to indicate the direction of swing or movement, and/or locking

security side of a door.

Handed (locks, etc.): A term used

to indicate that the article is for use only on doors of the

designated hand.

Harmon Hinge: A hinge designed to

swing a door into a pocket at a right angle with the frame.

Hasp: A fastening device consisting

of a loop and a slotted hinge plate, normally secured with

a padlock.

Hinge: Two plates pinned together

by a pin and attached to a door and its frame whereby a door

is supported and is enabled to swing or move.

Hinge Stile (of a door): The stile

to which the hinges are applied as distinguished from the

lock stile.

Horizontal Spring Hinge: A spring

hinge mortised horizontally into the bottom rail of a door

and fastened to the floor and head frame with pivots.

Hub: The part of a lock through which

the spindle passes to actuate the mechanism.

Inactive Door (or leaf): That leaf

of a pair of doors that does not contain a lock, but is bolted

when closed, and to which the strike is fastened to receive

the latch or bolt of the active door.

Indicator Button: A device used in

connection with a hotel lock to indicate whether or not the

room is occupied.

Integral (locks and latches): A term

used to describe a type of mortise lock having cylinder in

the knob.

Invisible Hinge: A hinge so constructed

that no parts are exposed when the door is closed.

Keeper: Synonymous with Strike.

Key Change: The combination of cuts

in a key that enable it to operate the lock for which intended.

Key Plate: A small plate or escutcheon

having only a keyhole.

Keyway: The aperture in lock cylinders

that receives the key and closely engages with it throughout

its length.

Kick Plate: A protective plate applied

on the lower rail of the door to prevent the door from being


Knob: A projecting handle for operating

a lock.

Knob Shank: The projecting stem of

a knob into which the spindle is fastened.

Knuckle: The enlarged part of a hinge

into which the pin is inserted.

Latch Bolt: A beveled spring bolt,

usually operated by a knob, handle or turn.

Leaf (of a pair of doors): One of

the two doors forming a pair of doors.

Lever Handle: A horizontal handle

for operating the bolt(s) of a lock.

Lever Tumbler: Flat tumbler having

a pivoted motion actuated by the turning of the key and controlling

the locking function.

Lip of a Strike: The projecting part

on which the latch bolt rides.

Lock Rail (of the door): The horizontal

member of a door intended to receive the lock case.

Lockset: A lock, complete with trim,

such as knobs, escutcheons or handles.

Lock Stile (of a door): The stile

to which the lock is applied as distinguished from the hinge


Loose Joint Hinge: A hinge having

two knuckles; the pin is fastened permanently to one knuckle,

the other contains the pinhole, whereby the two parts of the

hinge can be disengaged by lifting. These hinges are handed.

Loose Pin Hinge: A hinge having a

removable pin to permit the two parts of the hinge to be separated.

Magnetic Catch: A cupboard catch that

uses a magnet to hold the door closed.

Master Key: Operates any quantity

of cylinders of different individual key changes.

Masterkeying: An arrangement of cylinders

having individual key changes, which permits them all to be

operated by a simple key called a master key.

Mono Lock: See Preassembled Lock.

Mop Plate: A narrow plate similar

to a kick plate, of sufficient height to protect against the

swish of the mop.

Mortise: A cavity made to receive

a lock or other hardware; also the act of making such a cavity.

Mortise Bolt: A door bolt designed

to be mortised into a door rather than applied to its surface.

Mortise Lock (or Latch): A lock designed

to be installed in a mortise rather than applied to the door’s


Mullion: A fixed or movable post dividing

an opening vertically.

Nightlatch: An auxiliary lock having

a spring latch bolt and functioning independently of, and

providing additional security to, the regular lock of the


Overhead Concealed Closer: A closer

concealed in the head frame with an arm connecting with the

door at the top rail.

Panic Exit Device: See Exit Device.

Paracentric: A term used in connection

with cylinder plugs having projections on the sides of the

keyway that extend beyond the vertical center line of the


Pin Tumblers: Small sliding pins in

a lock cylinder, working against coil springs and preventing

the cylinder plug from rotating until the pins are raised

to the proper alignment by bitting of key.

Pivot: See Door Pivot.

Plug (of a cylinder): The round part

containing the keyway and rotated by the key to transmit motion

to the bolt(s).

Preassembled Lock: A lock that has

all the parts assembled as a unit at the factory, and when

installed in a rectangular notch cut into the door edge, requires

little or no disassembly.

Prison Lock: A heavy lock designed

especially for use on jail cells.

Push Plate: A plate applied to the

lock stile to protect the door against soiling and wear

Quadrant (Dutch Door): A device to

fasten together the upper and the lower leaves of a Dutch


Rabbet: A term used to describe the

abutting edges of a pair of doors so shaped as to provide

a tight fit. One half of the edge projects beyond the other

half, usually 1/2 . Also used to define that portion of a

door frame into which the door fits.

Rabbeted Lock (or Latch): A lock in

which the face conforms to the rabbet found on a rabbeted


Rail (of a door): A horizontal member

that pins the stiles. May be exposed as in a paneled door,

or concealed as in a flush door

Reinforcing Unit: A metal box-shaped

reinforcement for use in a metal door in which a bored lock

is to be installed. It provides both vertical and horizontal

latch support.

Reverse Bevel: See Bevel.

Reversible Lock: A lock which, by

reversing the latch bolt, may be used by any hand. On certain

types of locks, other parts must also be changed.

Rigid Lock: See Preassembled Lock.

Rim: A term indicating articles of

hardware designed for application to the surface of doors

and windows.

Roller Latch: A friction door latch

employing a roller latch head under spring tension, which

engages a strike having a recess formed to receive the roller.

Roller Strike: A strike having a rolling

member at the point of latch bolt contact to minimize friction.

Rose: A trim plate attached to the

door under the knob. It sometimes acts as a knob bearing.

Rounded Front: A lock or bolt front

conforming to the rounded edge of a double acting door. The

standard radius is 4″ (101.6 mm).

Screwless Knob: A knob attached to

a spindle by means of a special wrench as distinguished from

the more commonly used side knob screw.

Screwless Rose: A rose with concealed

method of attachment.

Shank (of a knob): The projecting

stem of a knob into which the spindle is fastened.

Side Knob Screw: A set screw used

to fasten a knob to a spindle.

Spindle (of a knob): The bar or tube

connected with the knob or lever handle that passes through

the hub of the lock or otherwise engages the mechanism to

transmit the knob action to the bolt(s).

Split Astragal: An astragal that is

split through the middle, allowing each door leaf to operate


Spring Hinge: A hinge containing one

or more springs to move the door into the desired position.

It may be either single or double acting.

Stile (of a door): A vertical member

of the door structure; each door has two, a lock stile and

a hinge stile.

Stop (of a lock): The button, or other

small device, that serves to lock the latch bolt against the

outside knob or thumb piece or unlock it if locked. Another

type holds the bolt retracted.

Store Door Handle: A heavy grip or

pull mounted on sectional or elongated plates and provided

with a thumb piece to operate the latch trip of a store door


Strap Hinge: A surface hinge of which

one or both leaves are of considerable length.

Strike: A metal plate or box that

is pierced or recessed to receive the bolt or latch when projected.

Sometimes called Keeper.

Surface Hinge: One having both leaves

surface applied.

Swinging Latch Bolt: A bolt that is

hinged to a lock front and is retracted with a swinging rather

than a sliding action. Sometimes called Hinged Latch Bolt.

Swivel Spindle: A spindle having a

joint midway in its length to permit the knob at one end to

be made rigid by the stop works while the other end is free

to operate.

T Handle: A cross handle for actuating

the bolt of a lock and used in place of a knob.

T Hinge: A surface hinge with the

short member attached to the jamb and the long member attached

to the door.

Template Hardware: A term indicating

any item of hardware that is made to template; that is, exactly

matching the master template drawing as to spacing of all

holes and dimensions.

Thimble: The socket or bearing attached

to an escutcheon plate in which the end of the knob shank


Three-Point Lock: A device sometimes

required on three-hour fire doors to lock the active leaf

of a pair of doors at three points.

Threshold: A strip fastened to the

floor beneath a door, usually required to cover the joint

where two types of floor material meet.

Throw (of a deadbolt or latch bolt):

Measurement of the maximum projection when bolt is fully extended.

Thumb Piece (of a handle): The small

pivoted part above the grip of a handle to be pressed by the

thumb to operate a latch bolt.

Transom Bar: That part of a door frame

that separates the top of a door or a window from the bottom

of the transom

Transom Catch: A fastener applied

to a transom and having a ring by which the latch bolt is


Transom Chain: A short chain used

to limit the opening of a transom; usually provided at each

end with a plate for attachment.

Transom Lift: A vertically operated

device attached to a door frame and transom by which the transom

may be opened or closed.

Tubular Lock (or Latch): A type of

bored lock

Tumbler: A guard or obstruction that

prevents operation of a bolt except by insertion of the proper


Turn Piece: A small knob, lever or

tee turn with spindle attached for operating the deadbolt

of a lock or a mortise bolt.

Two-Point Latch: A device sometimes

required on three-hour fire doors to lock the inactive leaf

of a pair of doors at top and bottom.

Unit Lock: See Preassembled Lock.

Universal: A term used to describe

a lock, a door closer or other device that can be used on

doors of any hand without change.

Vertical Spring Pivot Hinge: A spring

hinge mortised into the heel of a door and fastened to the

floor and head with pivots.

Ward: An obstruction projecting from

the lock case of side of a keyhole intended to prevent entrance

or rotation of an improperly cut key.