Technical Terms as Applied to Builders Hardware

Glossary

Technical Terms as Applied to Builders' Hardware

        ACTIVE DOOR - In a pair of doors, the active door is the one which must be opened first.

        ADJUSTABLE KEY - A key for sliding door locks, having a steam or shank adjustable as to its length to adjust the key to doors of various thickness.

        ANTI-FRICTION LATCH BOLT - The latch bolt of a lock, when provided with a device for diminishing the sliding friction of the bolt during the closing of a door. A small additional latch connected with a regular latch bolt. it engages the strike and retracts the regular latch.

        APARTMENT HOUSE LETTER BOX - A box for mail combined with a speaking tube mouth piece, and an electric push button; used in vestibules of apartment houses.

        ARMORED FRONT - A lock front for cylinder locks, consisting of two laminated plates, the tinder one of which is permanently riveted or screwed to the lock case and the outer plate secured to the under plate by means of screws.

        ASTRAGAL - A molding, usually half round, applied to the abutting edges of a pair of double or folding doors to break and cover the line of juncture or act as a stop.

        ASTRAGAL FRONT - A lock front of a form coinciding in shape with the edges of a door having an astragal molding.

        ASYLUM LOCK - A lock especially designed and adapted for use on doors of an insane asylum, being protected against tampering.

        AUXILIARY LATCH BOLT (GUARDLATCH) - A latch bolt separate from the regular latch bolt which
remains retracted when the door is closed and automatically dead locks the regular latch against end pressure.

        AUXILIARY SPRING - Adevice applied under a rose to hold a lever handle in a horizontal position.

        BACKPLATE (RIM CYLINDER) - Asmall plate applied to the inside of the door through which the cylinder connecting screws are passed.

        BACKSET OF A LOCK - The distance horizontally from the front to the center of the knob or key hole.

        BEARING PLATE - Aflat rose for early wooden glass knobs with wide shanks.

        BALL BEARING BUTT - A butt having a roller or ball bearing to reduce the friction.

        BAR HANDLE - A door handle consisting of a bar, usually horizontal, supported by one or more projecting brackets.

        BARN DOOR LATCH - A heavy thumb latch.

        BARREL BOLT - Acylindrical bolt mounted on a plate having a case projecting from its surface to contain and guide the bolt.

        BARREL KEY - Around key having a hole drilled into its end to fit over a drill pin in the lock. Used chiefly for cabinet locks. Synonymous with pipe key.

        BELL CRANK - A bent arm, usually a right angle, turning on a pivot attached to a plate, used for altering the direction of bell wires.

        BELL PULL - A knob, with plate, arranged to pull out longitudinally against the resistance of a spring, its motion being transmitted through wires to a bell.

        BEVEL OF BOLT - A term used to indicate the direction in which the bevel of the latch bolt is inclined; "regular bevel" commonly indicating a lock for use on a door opening inward and "reverse bevel" for a door opening outward

        BEVEL OF DOOR - The angle made by the edge of a door with the sides of the lock stile, if other than 90 degrees.

        BEVEL OF LOCK FRONT - The angle of the front of a mortise lock, when inclined at other than a right angle to the case, to conform to the angle of the edge of the door.

        BIT (OF A KEY) - A projecting blade which engages with and actuates either or both the bolt and tumblers of the lock. The part of a key that is cut to operate a lock.

        BIT-KEY LOCK - Alock operated by a key having a wing bit.

        BITTING - A cut or indentation on that part of a key which acts upon and sets the tumblers.

        BOLT - A bar or barrier arranged to secure a door or other moving part, and to prevent its opening.

        BOLT (NECKED) - A bolt, the projecting end of which has a bend or offset to engage with a strike or keeper not in line with the body of the bolt.

        BOSTON SASH FAST - A type of sash fast in which the rotating locking bar is held in the locked position by a trigger or thumb piece, pressure on which permits the bar automatically to unlock.

        BOTTOM BOLT - A general term covering any bolt specifically designed for use on the bottom of a door only.

        BOW - The portion of the key that is held between the fingers.

        BOX STRIKE - A strike in which the aperture to receive the bolt is enclosed or boxed.

        BRACKET BEARING - A knob thimble, or socket which projecting like a bracket, supports the knob close to its head instead of at the end of the shank.

        BUILDERS' FINISHING HARDWARE - A term to designate the locks, hinges and other metallic trimmings used on buildings for protective and decorative purposes; as distinguished from "Rough Hardware," which includes such building items as nails, registers, ash pit doors, stanchions, sash weights, sash cord, sash chain, pulleys, etc.

        BUTT - An abbreviation of the term butt hinge. A hinge intended for application to the butt or edge of a door, in contradistinction to a flat or strap hinge for application to the surface of a door.

        BUTT (HALF SURFACE) - A butt with one leaf mortised in frame, the other applied on the surface of the door.

        CABIN DOOR LOCK - A hook and its staple, each with a heavy plate for attaching. Used shipboard to hold a door at either end of its swing.

        CABINET LOCK - A small cylinder, bit, or flat key lock used on cabinet work or furniture.

        CARD PLATE - A holder used on drawers or doors and formed to hold a label or card.

        CAM - A rotating piece, either non-circular or eccentric, used to convert rotary into reciprocating motion; e.g., the wing of a bit key or a cylinder cam, which converts rotary into reciprocal motion when actuating the bolts of a lock.
        CAM (OF A CYLINDER) - A rotating piece attached to the end of the cylinder plug to operate the locking mechanism.

        CAP(OF A LOCK) - The removable lid of a lock case. Synonymous with "cover."

        CAPPED BUTT - A butt having on each leaf a cap which covers the fastening screws and is itself attached to the butt by one or more smaller screws.

        CASEMENT ADJUSTER - A fringed or pivoted rod for moving and fastening the hinged sash of a casement or French window.

        CASEMENT FASTENER - A catch for fastening a casement or French window.

        CASEMENT WINDOW - A window (sash) hinged at the sides to open horizontally in or out.

        CEILING HOOK - A hook for use in ceilings, or on the underside of a shelf, and usually having two prongs.

        CATCH - A flat metal fitting applied to t door jamb designed to catch the latch of a thumb latch as it falls.

        CHAIN BOLT - A bolt for application at the top of a door, and having a chain depending therefrom, whereby the bolt may be retracted against the resistance of a spring which tends to hold it in the locked position.

        CHAIN DOOR FASTENER - Aheavy chain, one end of which is secured to a plate which may be attached to the edge of the door, the other end of the chain carrying a ball or hook, which may be inserted in a slot formed in another plate attached to the jam or other half of the door, whereby the door cannot be opened (except slightly) until the chain is released.

        CHANGE KEY - Akey which will operate only one lock in a series, as distinguished from a master key which will operate all locks in a series.

        CHANGES (KEY) - The different bittings or tumbler arrangements in a series.

        CITY LOCK - (1904 Towne usage) A nearly obsolete term, used in New York City and vicinity; formerly indicating a superior grade of handmade locks, but now usually applied to an inferior grade of rim and mortise locks with brass bolts and steel or brass keys.

        CLOSET KNOB - Asingle knob on one end of a spindle, on the other end of which is a rose or plate to secure the knob and spindle to the door; for use on closet doors.

        COAT AND HAT HOOK - A hook with two or more projections, one of which is of sufficient length to receive a hat, the others being usually shorter.

        COMBINATION LOCK - A lock having changeable tumblers actuated by a dial on the face of a door, permanently connected by a spindle with the lock mechanism.

        COMBINED ESCUTCHEON PLATE - A plate containing both a key hole and a knob rose.

        COMBINED STORE DOOR LOCK - A lock containing a heavy dead bolt and a latch bolt adapted to be operated by thumb handles instead of knobs.

        COMMUNICATING DOOR LOCK - A lock, usually having a latch bolt and two dead bolts, one dead bolt of which is controlled by a turn knob or key from one side only, and the other dead bolt from the opposite side only, each independently of the other.
        COMPENSATING-HUB - A lock hub having an elongated spindle-hole to compensate for the shrinking and swelling of a door and to prevent derangement of the lock and binding from other causes.

        CORNER PLATE - A plate similar to a finger or push plate, but having two arms, forcing a right angle, and adapting it for application to the corner of a door.

        CORRUGATED KEY - A key with pressed longitudinal corrugations in its shank to correspond to an irregularly shaped key way.

        COTTAGE LATCH - A small lift latch for use on Cupboards and light doors.

        CRANK HANDLE - Synonymous with "lever handle."

        CREMONE BOLT - A fastening for casement or French windows arranged for application to the surface thereof, consisting of a sliding rod, engaging at top and bottom with strikes or plates in the window frame, and providing near its center with a handle or knob the rotation of which causes the upper and lower parts of the bolt to move in opposite directions in locking or unlocking, and sometimes provided with an additional horizontal bolt, also operating simultaneously, which serves further to secure the sash at or near its center.

        CUP ESCUTCHEON - A door plate, for use on sliding doors, having a recessed panel to afford finger hold and to contain the knob, or its equivalent, and a key, all of the contained parts being flush with the surface of the plate in order to offer no obstruction to the movement of the door within its recess.

        CUPBOARD BUTTON - A small turning bar, adapted to secure a door.

        CUPBOARD CATCH - A small spring catch adapted for fastening a light door, and operated by a slide knob or thumbpiece.

        CUPBOARD LOCK - A lock designed for use on doors of cupboards, boxes, etc.
        CUPBOARD TURN - A small spring-catch adapted for fastening a light door and operated by a rotating knob or handle.

        CURVED LIP STRIKE - The lip of a strike curved to conform to a detail, to protect door casings and to prevent the catching of wearing apparel on the projecting lip.

        CYLINDER (OF A LOCK) - A cylindrically shaped device containing the key controlled mechanism and cam or spindle for actuating the bolts of a lock.

        CYLINDER LOCK - A lock having a removable tumbler assembly contained in a cylindrical case.

        CYLINDER COLLAR - A decorative plate placed under the head of a cylinder to give a finished appearance.

        CYLINDER RING - A rose or washer, placed under the head of a cylinder to permit the use of a long or standard cylinder on a thin door.

        CYLINDER SCREW - The set screw in the front of a mortise lock to prevent the unscrewing of a cylinder.

        CYLINDRICAL - A term used to describe locks with a cylindrical case which has a separate latch bolt case that fits into the cylindrical lock case.

        CYCLOID KNOB ACTION - An arrangement of intergeared pivotal levers for transmitting motion from a lock hub to the latch bolt. First introduced in the "Vulcan Locks."

        DEAD BOLT (OF A LOCK) - The projecting member of a lock that is operated by key or turn-knob to positively lock a door, and usually is rectangular.

        DEAD LOCK - A lock with a dead bolt only, controlled by key from either side or by key from one side and turn knob from the other side.

        DETACHABLE KEY - A key so constructed that the bits, or portion which actuates the tumblers, may be detached from the shank or handle of the key for convenience in carrying. Formerly much used with bank locks requiring large and heavy keys.

        DISC-TUMBLER - Aflat, circular, or oval shaped disc with rectangular hole and one or more side projections. A number are used side by side.

        DOOR BOLT - A sliding rod or bar, suitably mounted for attachment to a door and adapted to secure it.

        DOOR CHECK - A device for preventing the slamming of doors provided with springs. Synonymous with "door check and spring."

        DOOR CHECK AND SPRING - A device combining, in one structure, a door spring and a check to prevent slamming of the door.

        DOOR CLOSER BRACKET - A device whereby a door closer may be installed on the stop or push side of a door. Brackets are of several different types for various applications.

        DOOR HOLDER - A device for fastening a door in an open position.

        DOOR PULL - A bent handle usually mounted on a plate, and adapted for attachment to the surface of a door.

        DOOR STOP - A means to limit the swing of a door and generally applied on floor or wall base.

        DOUBLE ACTING SPRING HINGE - A device for hanging a door and allowing it to swing in either direction. in addition, the hinge has two springs which return the door from either open position or the closed.

        DOUBLE-BITTED KEY - A key having bittings on both sides, where either or both wings or sides of the key may actuate the tumblers.

        DOUBLE-HUNG WINDOW (SASH) - A window with two vertical sashes sliding Lip and down.

        DOUBLE-THROW BOLT - A bolt controlled by a mechanism which permits extra projection or "throw" of the bolt, giving greater security.

        DRAW BACK BOLT - A bolt (or slide) of handle or curved shape extending from the side of the lock case opposite the face. When drawn, it retracts the latch.

        DRAW BACK LOCK - A lock having a latch operated from the inside by a draw back bolt extending from the side of the case opposite the face. May or may not have a stop to hold the latch against the key that operates the lock from the outside.

        DRAWER KNOB - A small knob used for pulling open a drawer.

        DRAWER PULL - A small handle or grip used similar to a drawer knob.

        DRILL PIN - A round pin projecting from the back plate of a lock and fitting into a hole in the end of the key.

        DRIVERS - The upper set of pins in a pin-tumbler cylinder which, activated by the springs, projects into the plug until raised by insertion of the key to proper point for unlocking.

        DROP - The distance from the front edge of selvage to the center of cylinder or key hole in cabinet locks.

        DROP DRAWER-PULL - A pull or handle pivoted at its ends to its attaching plate.

        DROP ESCUTCHEON (OR KEYPLATE) - An escutcheon having a pivoted covering for the key hole.

        DROP HOOK - Synonymous with "shutter bar."

        DROP KEY - A key having a bow, or handle, pivoted to the shrink, so that it may drop or fall parallel with the surface of the door.

        DUMMY CYLINDER - A non-active cylinder which can be attached to a cylinder collar or escutcheon for use as dummy trim.

        DUMMY TRIM - Trim only, without lock or working parts, applied to the inactive door of a pair of doors and matching the trim on the active door. This is for the purpose of balancing the hardware ornamentation on a pair of doors.

        DUPLEX LOCK - A master key lock of the cylinder type, such as the "Yale Lock," provided with two cylinders on the same side, both acting on the same bolt, but each controlled by a different key.

        DUST PROOF STRIKE - A strike with spring controlled shutters which automatically close the strike opening when the lock bolts are withdrawn.

        DUTCH DOOR - A door cut horizontally through the lock rail so that the upper part of the door may be opened independently of the lower door.

        DUTCH DOOR BOLT - A bolt for locking together the upper and lower halves of a Dutch door.

        EASY SPRING - A term used in referring to the construction of a knob operated lock or latch. it indicates that the spring action on the latch bolt is "easy" while the knob action is "snappier." This is usually accomplished by the use of separate springs for each.

        ELBOW CATCH - A catch with a pivoted L- shaped member of which one end engages a strike or staple and the other end forms a handle to release the catch.

        ELECTRIC STRIKE - (Electric Door Opener.) A lock strike equipped with an electrically controlled retracting device operated by push buttons in various locations throughout a building, usually in each apartment of an apartment house. By pressing the electric push button, a small electromagnet retracts a section of the strike, thus releasing the lock bolts and permitting the door to open.

        ELLIPSOID KNOB - A door knob of oval design.

        ESCUTCHEON - Generally a plate containing a key hole.

        ESCUTCHEON PLATE - A protective metal plate, applied to the surface of the lock stile, with or without cylinder hold or key hole but with knob socket.

        ESCUTCHEON KNOB - A door knob containing a key hole for the key which actuates the lock or controls the rotation of the knob.

        ESPAGNOLETTE BOLT (BAR) - A fastening for French windows (doors) or casement windows, arranged for application to the surface, consisting of rotating rods extending from the top to the bottom with hooks at each end which engage with pins or plates in the window frames when the bar is rotated, and having a hinged handle near the center whereby the bar may be rotated to fasten or release the sash.

        EXTENSION BOLT - Aflush bolt having a short plate to receive a knob or thumb piece, of which the latter is connected at the bolt end at the top or bottom of a door by an extension rod inserted through a hole bored in through the thickness of a door.

        FACE (OF A LOCK) - The plate surface which shows at edge of door after installation.

        FAST PIN JOINT BUTT - A butt in which the pin is permanently fastened.

        FENCE (OF A LOCK) - A projecting piece, usually attached to the tail of the dead bolt, which passes through the"gating" of the lever tumblers when they are property aligned, permitting the bolt to be projected or retracted.

        FINISHING HARDWARE - Hardware which may be considered as part of the decorative or finished treatment of a room or building.

        FIRE EXIT BOLTS - Bars applied on the inside surface of a door which allow ready or emergency exit from a building or room. Pushing on a crossbar instantly releases the mechanism that fastens the door in the close position.

        FLAT KEY - A thin, flat, stamped key, usually made of steel, having square-cut bitting on one or both sides and sometimes containing longitudinal grooves.

        FLOOR HINGE - A pivot hinge that is set in the floor. It may be spring type only or may combine liquid control with the spring closing power.

        FLUSH BOLT - A door bolt so designed that when applied, the surface is flush with door.

        FLUSH CUPBOARD CATCH - A catch which is half mortise, i. e., let in flush with face of door.

        FLUSH PLATE - A door plate of any kind intended to be let into the wood flush with its surface.

        FLUSH RING - A flush circular door pull that is mortised in door.

        FLUSH RING CUPBOARD CATCH - A catch with a flush ring in place of a knob for actuating the bolt.

        FOLDING KEY - A key having a handle and a blade or shank, hinged together, the blade folding in half or into the handle like a jack knife.

        FOOT BOLT - A spring bolt for the bottom of a door which, when retracted, is retained by a trigger, the release of which later permits the spring to shoot the bolt into the locked position.

        FRENCH DOOR - A full length glass paned door. Sometimes called a French window or a sash door.

        FRENCH ESCUTCHEON - A small circular key plate secured by driving or screwing into the wood.

        FRENCH SHANK - A term used to indicate an ornamentally shaped knob shank.

        FRENCH WINDOW - A window mounted on hinges like a door; a casement window extending to the floor.

        FRENCH WINDOW LOCK - A mortise knob lock with a narrow backset, for use on French windows or doors with narrow Stiles.
        FRONT (OF A LOCK) - The face plate of a mortise lock through which the ends of the bolts are projected.

        FRONT DOOR LOCK - A lock for use on entrance doors, having a dead bolt and a latch bolt, the former controlled from the outside by a key and from the inside by a key or knob; the latter controlled from the outside by a key and from the inside by a knob. Usually provided with "stop work" whereby the outside knob may be set to actuate the latch bolt or not, as desired.

        GATING - The opening in the tumbler of a lock into or through which the fence passes to release the bolt or permit its movement.

        GRILLE - A protective screen of open metal work, either wrought or cast; sometimes highly ornamental.

        GUARD BAR - A protective bar used on screen door or windows.

        GUARD LOCK - A lock which guards or checks another lock; especially that part of the mechanism of a safe deposit lock which is controlled by the attendant's key, and which checks or guards the other part of the mechanism controlled by the renter's key.

        GUARD-FRONT LOCK - Also referred to as "recessed front lock." It has a specially constructed front and strike. When these are interlocked the latch bolt is protected against tampering through the crevice or the door.

        GUN SPRING - Aflat wire coiled spring used frequently in French door locks to maintain the lever handle in a horizontal position.

        HALF-RABBETED LOCK - A mortise lock, the front of which is turned into two planes, at right angles, thus adapting it for use on a door with rebate on edge. A lock having a front in two planes forming a single right angle.

        HAND AND BEVEL OF LOCKS - The inclination or bevel of the latch bolt and the lock front always corresponds in direction with the bevel of the door, If no bevel is designated it is understood to be regular bevel. The hand of such a lock is the same as the hand of the door.

        HAND RAIL BRACKET - A support for stair hand rails,

        HAND (OF LOCKS, ETC.) - A term indicating whether the article is adaptable for use on a right or left hand door.
        HANDED - A term indicating that the article is adaptable for use on either a right hand or left hand door, but not both.

        HINGED OR SWINGING LATCH BOLT - A bolt which is hinged to the lock front and is retracted with a swinging rather than a sliding action.

        HORIZONTAL LOCK - A lock whose major dimension is horizontal.

        HOTEL LOCK - A type of master-keyed lock, usually having a latch bolt and either one or two dead bolts.

        JAMB - The inside vertical face of a door or window frame.

        KEEPER - Synonymous with "strike."

        KEY ESCUTCHEON - A small plate with key hole only.

        KEY HOLE - The aperture in a lock case Or escutcheon plate through which the key passes in entering the lock. See also "key-way."

        KEY PLATE - A plain or ornamental plate having a key hole (but no knob socket) to he attached to the surface of a door.

        KEY TAG - A metal or fiber identification tag to be attached to keys.

        KEY-WAY - The aperture throughout the length of a lock cylinder, into which the key is inserted.

        KICK PLATE - A plate adapted for application near the bottom of the door for protecting the surface.

        KNOB - A projecting handle, usually round or spherical, for operating a latch bolt. A small crescent or otherwise shaped knob designed for operation with the fingers is called a "turn-knob" or sometimes known as a "thumb turn" or "thumb knob" and is usually employed to "throw" the dead bolt of a lock from the inside.

        KNOB BOLT - A dead bolt which is controlled by a knob from either or both sides of the door, and not actuated by a key.

        KNOB LATCH - A door latch having a spring bolt only, operated by knobs.

        KNOB LOCK - A door lock having a spring latch operated by knobs and a dead-bolt.

        KNOB ROSE - A small plate which acts as a knob bearing and protective or ornamental shield applied to the surface of a door.

        KNOB SCREW - Aset (or other) screw to fasten a knob to a spindle.

        KNOB SHANK - The projecting stem of a knob containing the hole or socket to receive the spindle.

        KNOB TOP - The upper and larger part of a knob which is grasped by the hand.

        KNUCKLE - The part of a hinge or butt which encloses the hinge pin.

        LATCH - A door fastening device, having a spring-bolt, but usually with no locking functions,

        LATCH-BOLT (OF A LOCK) - A beveled spring-bolt, usually operated by knob, lever handle or thumb piece.

        LETTER BOX BACK PLATE - A plate attached to the inside of the door to finish off the opening of the letter drop.

        LETTER BOX HOOD - A cover to conceal the opening and to direct the mail floorward.

        LETTER BOX PLATE - A cast or wrought plate, attached to the door, with an opening to permit insertion of mail.

        LEVER BELL PULL - A pull actuated by lever action in place of by drawing out of knob.

        LEVER CUPBOARD CATCH - One consisting of a lever pivoted on a plate, through which it passes, its inner end having a hooked form to engage with a staple, and its other end formed into a knot or handle.

        LEVER HANDLE - A horizontal handle for operating the latch bolt of a lock.

        LEVER TUMBLER LOCK - Also called bit-key lock. The obstacle in this type of lock consists of one to five flat tumblers. These must be lifted by the bittings, or grooves, cut in the bit of the key, before the bolt can be thrown.

        LOCK (INVERTED) - A lock with the key hole above the knot or handle.

        LOCK STILE (OF A DOOR) - The stile to which the lock is applied, as distinguished from the hinged stile.

        LOCKER RING - A Pull, for mortising into the edge of a sliding locker door, consisting of a plate containing a ring which may be pushed back flush with the plate or pulled forward for use is a pull to open the door.

        MORTISE - An opening made to receive a lock or other hardware; also the act of making such an opening.

        MORTISE BOLT - A door bolt designed to be mortised into it door, instead of being applied to its Surface.

        MORTISE LOCK OR LATCH - A lock or latch designed to be mortised into the edge of a door, not applied to the surface.

        MUNTINS - The small members, either vertical or horizontal, dividing the glass door or windows.

        NAME PLATE - A plate containing a name, as for front door use; also applied to a plate containing the name, address, and business of the maker of a machine or other article to which the plate is attached.

        NIGHT KEY - The one of two keys of a front door lock which controls the night work and operates the latch bolt.

        NIGHT LATCH - An auxiliary lock having a spring-latch bolt and functioning independently and providing additional security to the regular lock on the door.

        NIGHT WORKS (STOPWORKS) - Interior mechanism of a lock which dead locks the latch bolt against the outside knob or thumb piece. This mechanism is controlled by buttons in the front of the lock or by the inside cylinder.

        NON-FERROUS - Non-rusting. Containing no iron.

        NOSE PLATE - A small plate which surrounds the nose or escutcheon of a cylinder lock where the cylinder is permanently attached to the lock.

        OFFICE LOCK - A lock usually having a latch controlled from both sides by knobs, with the latch arranged to be set by stops so that the outside knob may be rendered inoperative and entrance be gained by key only. The inside knob is always operative. if the stop is set, the door locks when closed. A dead bolt or knob bolt may also be incorporated.

        OFFICE LOCK - (1904 Towne usage.) An arbitrary term applied to a knob lock of inverted form, i.e., with the key hole ,, above the knot, and especially designed for use on office doors.

        OUTSIDE - Term used to indicate the side from which the hand and bevel of locks are determined, usually the outside of an entrance door, the hall side of a room door, and the room side of a closet door. It is less confusing to determine the hand and bevel of a lock from the side having the more important key function or, if the key function is the same on both sides, from the side on which the butts are visible.

        PANIC BOLT - Synonymous with "fire exit bolt."

        PARACENTRIC KEY - A key for cylinder locks with longitudinal ribs and grooves on both sides projecting beyond the center line to prevent picking.

        PARLIAMENT BUTT - Abutt having T-headed leaves, usually broad.

        PERMUTATION LOCK - Aterm formally applied to a lock having changeable tumblers, whether actuated by key or by dial.

        PIN-TUMBLERS - Small sliding pins in a lock cylinder, working against coil springs and preventing the cylinder plug from rotating until raised to exact height by bitting of key.

        PIPE KEY - A key having a hole drilled in the end of the post to fit over a pin in the lock.

        PLATE ESCUTCHEON - Synonymous with "key plate."

        PLUG (OF A LOCK) - The cylindrical part, housed by the "shell" of a lock cylinder, which contains the cylinder keyway.

        PLUG RETAINER - The part which retains the plug in a cylinder lock.

        POST (OF A KEY) - The round part of bit-key to which the wing or bit is attached.

        PULL BAR - Abar attached to a door in contradistinction to a push bar.

        PULL DOWN HANDLE - A light handle for attachment to the underside of the bottom rail of tipper sashes for use in moving the latter.

        PULL DOWN HOOK - synonymous with "sash hook."

        PULLEY STILE - The vertical sides of a double hung sash casing to which the pulley are applied.

        RABBET - The offset on the abutting edge of a pair of doors, or the corresponding offset of the fronts and strikes of rabbeted locks.

        RABBETED LOCK - A lock in which the front is formed in two planes or steps corresponding to the rabbeted edge of a door.

        RABBETED LOCK - (1904 Towne usage.) A mortise lock, the front of which is formed with an offset or rebate conforming to the corresponding rebate on the edge of the door. A lock having a front in three planes, forming two right angles.

        RAIL (OF A DOOR) - Any of the horizontal members which enclose the panels and which, with the stiles, constitute the framework.

        REACH (OF A TRANSOM LIFT) - The distance from center of operating rod to the nearest edge of the transom sash.

        RECESS (OF A TRANSOM LIFT) - The distance inward front the face of the door casing to the face of the transom sash.

        REVERSE BEVEL (OF A LATCH BOLT) - A term used to indicate that the bevel of the latch bolt is reversed, or inclined in the opposite direction to that which is regular.

        REVERSED DOOR - A door opening in the opposite direction to that which is usual or regular. Room doors if opening inward are "regular," if opening outward are "reversed." Cupboard doors are regular when opening out.

        RIM LOCK OR LATCH - A lock or latch which is applied to the surface of the door, not mortised into it.

        ROLL BACK - A rotating piece within a lock, permanently attached to the knob spindle, for transmitting motion to the bolt. Inaccurately used as synonymous with "hub."

        ROSE - A small plate which acts as a knob bearing, with sockets of varying depth for supporting and guiding the shank of a knob or lever.

        ROSE (AUXILIARY) - A rose equipped with a spring on the underside for the purpose of holding a lever handle in a horizontal position.

        ROUND KEY - A key having a round shank or stem.

        SASH LOCK - Afastening controlled by a key, and adapted to secure a sash.

        SASH PIN - A form of window spring bolt.

        SASH PULL - A handle for attachment to the underside of the lower rail of an upper sash of a double-hung window, for pulling down the sash. Synonymous with "window pull down" or "pull down handle."

        SASH RIBBON - A thin metal band adapted for use with sliding sashes in place of cord or rope.

        SASH SOCKET - A metal plate containing a hole or cup adapted to receive a sash hook.

        SASH WEIGHT - A weight used to balance sliding sashes; usually of cast iron and of long cylindrical form.

        SELVAGE or SELVEDGE - (1928 Thomas usage.) Refers to cabinet locks of the half-mortised type. The face of such a lock, mortised in flush with the inside stile of the door, is referred to as the selvage.

        SHIP LOCK - Alock wholly of brass for use on ships; usually of heavy construction.

        STRIKE - A metal fastening, on the door frame, into which the bolt or lock is projected to secure the door. Applied both to the flat plate used with mortise locks, and to the projecting box used with rim locks. Synonymous with "striker," "striking plate," and "keeper."

        TAIL PIECE - The sliding part or connecting link through which the bolt is operated by hub or key,
        therein.

        THUMB BOLT - A door bolt operated by a rotating thumb piece or a small knob.

        THUMB LATCH - A door fastening consisting of a pivoted bar which crosses the joint of the door to engage with the strike on the jamb, the free end of the bar being raised to disengage it from the strike on the jamb, by a transverse pivoted bar passing through the door, the latter bar operated on one side by the thumb and on the other side by the finger.

        THUMB PIECE - A still knob, usually operating independently a part of the locking device.

        UPRIGHT LOCK - A lock whose major dimension is vertical.

        WARDED KEY - A key having grooves or notches designed to clear corresponding wards or projections in the lock case or key hole.

        WING KEY - A key having a projecting wing or bit for operating the tumblers and/or bolt of a lock. Synonymous with "bit key."