Locksmith Glossary

ALOA

The Associated Locksmiths of America.

Associated master key

n. a master key which has particular change keys related directly to its combination through the use of constant cuts

Backplate

A plate on the inside of a door through which the cylinder connecting screws and tailpiece is passed.

Backset

The horizontal distance from the edge of a door to the center of a lockset.

Barrel Key

A key with a bit projecting from a hollow cylindrical shaft.

Bi-Lock

A pin tumber cylinder lock consisting of two parallel rows of pin tumblers and two sidebars operated by a U shaped key.

Bible

n. that portion of the cylinder shell which normally houses the pin chambers, especially those of a key-in-knob cylinder or certain rim cylinders

Bit

1. n. the part of the key which serves as the blade, usually for use in a warded or lever tumbler lock
2. v. to cut a key

Bit Key

A key with a bit projecting from a solid cylindrical shank. The bit has cuts to bypass the wards or operate levers in the correct lock.

Bit Key Lock

A warded or lever lock that uses bit keys.

Bitting

A cut, or series of cuts, on the bit or blade of a key.

Bitting Depth

n. the depth of a cut which is made into the blade of a key

Bitting List

n. a listing of all the key combinations used within a system. The combinations are usually arranged in order of the blind code, direct code, and/or key symbol.

Blade

The part of the key that is inserted into the lock.

Blank

A key before any cuts have been made, or a key that is not fully cut and is thus not yet operational.

Blind Code

n. a designation, unrelated to the bitting, assigned to a particular key combination for future reference when additional keys or cylinders may be needed

Bow

n. the portion of the key which serves as a grip or handle

Bow Stop

n. a type of stop located near the key bow

Broach

1. n. a tool used to cut the keyway into the cylinder plug
2. v. to cut the keyway into a cylinder plug with a broach

Build-up Pin

n. the additional element of a pin stack required to allow operation at independent shear lines in a cylinder

Building Master Key

n. a master key which operates all or most master keyed locks in a given building

cam

n. a flat actuator or locking bolt attached to the rear of a cylinder perpendicular to its plug and rotated by the key

cam lock

A lock that has an attached cam that serves as the lock`s bolt. Cam locks are often used on cabinets, file cabinets and drawers.

capping block

n. a holding fixture for certain interchangeable cores which aids in the installation of the caps

case ward

Protrusions that stick out of the sides of the keyway to allow entry of only the correct type of key blank.

chamber

n. any cavity in a cylinder plug and/or shell which houses the tumbler(s)

change key

The key that operates one lock in a masterkeyed suite.

CK

1. abb. change key 2. abb. control key

CMK

abb. construction master key

CMK`d

abb. construction master keyed

code

A series of numbers or digits on a key or lock that specifies or references the particular cuts of the key to operate a lock.

combination

n. the group of numbers which represent the bitting of a key and/or the tumblers of a lock or cylinder

concealed shell cylinder

n. a specially constructed (usually mortise) cylinder. Only the plug face is visible when the lock trim is in place.

constant cut

1. n. Any bitting(s) which are identical in corresponding positions from one key to another in a keying system. They usually serve to group these keys together within a given level of keying, and/or link them with keys of other levels.

construction core

n. an interchangeable or removable core designed for use during the construction phase of a building. The cores are normally keyed alike and, upon completion of construction, they are to be replaced by the permanent system`s cores.

construction master key

n. a key normally used by construction personnel for a temporary period during building construction. It may be rendered permanently inoperative without disassembling the cylinder.

construction master keyed

adj. of or pertaining to a cylinder which is or is to be operated temporarily by a construction master key

control cut

1. n. any bitting which operates the retaining device of an interchangeable or removable core

control key

A key used to remove the core from a removable core or interchangeable core cylinder.

control lug

n. that part of an interchangeable or removable core retaining device which locks the core into its housing

control sleeve

n. the part of an interchangeable or removable core retaining device which surrounds the plug

controlled cross keying

n. a condition in which two or more different keys of the same level of keying and under the same higher level key(s) operate one cylinder by design; e.g., XAA1 operated by AA2 ( but not XAA1 operated by AB1) NOTE: This condition could severely limit the security of the cylinder and the maximum expansion of the system when (1) more than a few of these different keys operate a cylinder, or (2) more than a few differently cross keyed cylinders per system are required.

core

n. a complete unit, often with a figure 8 shape, which usually consists of the plug, shell, tumblers, springs, plug retainer and spring cover(s). It is primarily used in removable and interchangeable core cylinders and locks.

cross keying

n. the deliberate process of combinating a cylinder (usually in a master key system) to two or more different keys which would not normally be expected to operate it together. See also `controlled cross keying,` `uncontrolled cross keying.`

cuts

A cut, or series of cuts, on the bit or blade of a key.

cylinder

n. a complete operating unit which usually consists of the plug, shell, tumblers, springs, plug retainer, a cam/tailpiece or other actuating device, and all other necessary operating parts

cylinder key

A key for use with pin tumbler and wafer tumbler cylinder locks.

deadbolt

A lock bolt, usually rectangular, that has no spring action, and that becomes locked against end pressure when fully projected.

deadlatch

A lock with a beveled latch bolt that can be automatically or manually locked against end pressure when projected.

deadlock

A lock that projects a deadbolt.

depth

The depth of a cut is measured from the bottom of the blade up to the bottom of a cut. Depths are numbered starting with #0 (or sometimes #1) as the highest depth.

depth key

A special key that enables a locksmith to cut blanks made from a particular lock according to a key code.

display key

n. a special change key in a hotel master key system which will allow access to one designated guest room, even if the lock is in the shut out mode. It may also act as a shut out key for that room.

drivers

The pins in a lock that sit on top of the lower pins.

ejector hole

n. a hole found on the bottom of certain interchangeable cores under each pin chamber. It provides a path for the ejector pin.

ejector pin

n. a tool used to drive all the elements of a pin chamber out of certain interchangeable cores

emergency key

n. the key which operates a privacy function lockset

emergency master key

n. a special master key which usually operates all guest room locks in a hotel master key system at all times, even in the shut out mode. This key may also act as a shut out key.

EMK

abb. emergency master key

ENG

symbol for engineer`s key

engineer`s key

n. a selective master key which is used by maintenance personnel to operate many locks under different master keys in a system of three or more levels of keying

GGGMK

abb. great great grand master key

GGGMK`d

abb. great great grand master keyed

GGM

abb. great grand master key

GGMK

abb. great grand master key

GGMK`d

abb. great grand master keyed

GM

abb. grand master key

GMK

abb. grand master key

GMK`d

abb. grand master keyed

grand master key

The highest level masterkey that fits all the locks in a multi-level masterkeyed system.

grand master key system

n. a master key system which has exactly three levels of keying

grand master keyed

adj. of or pertaining to a lock or cylinder which is or is to be keyed into a grand master key system

great grand master key

n. the key which operates two or more separate groups of locks which are each operated by a different grand master key

great grand master key system

n. a master key system which has exactly four levels of keying

great grand master keyed

adj. of or pertaining to a lock or cylinder which is or is to be keyed into a great grand master key system

great great grand master key

n. the key which operates two or more separate groups of locks which are each operated by different great grand master keys

great great grand master key system

n. a master key system which has five or more levels of keying

great great grand master keyed

adj. of or pertaining to a lock or cylinder which is or is to be keyed into a great great grand master key system

grooves

Long narrow milled out areas along the sides of the blade to allow the blade to bypass the wards in the keyway.

guest key

n. a key in a hotel master key system which is normally used to unlock only the one guest room for which it was intended, but will not operate the lock in the shut out mode

hardware schedule

n. a listing of the door hardware used on a particular job. It includes the types of hardware, manufacturers, locations, finishes, and sizes. It should include a keying schedule specifying how each locking device is to be keyed.

high security cylinder

n. a cylinder which offers a greater degree of resistance to any or all of the following: picking, impressioning, key duplication, drilling or other forms of forcible entry

HKP

abb. housekeeper`s key

hollow post key

A key with a bit projecting from a hollow cylindrical shaft.

housekeeper`s key

n. a selective master key in a hotel master key system which may operate all guest and linen rooms and other housekeeping areas

housing

n. that part of a locking device which is designed to hold a core

jamb

The inside vertical face of a doorway or window frame.

KA

abb. keyed alike

KD

abb. keyed different

key

n. a properly combinated device which is, or most closely resembles, the device specifically intended by the lock manufacturer to operate the corresponding lock

key bitting array

n. a matrix (graphic) display of all possible bittings for change keys and master keys as related to the top master key

key bitting punch

n. a manually operated device which stamps or punches the cuts into the key blade, rather than grinding or milling them

key blank

n. any material manufactured to the proper size and configuration which allows its entry into the keyway of a specific locking device. A key blank has not yet been combinated or cut.

key code

A series of numbers or digits on a key or lock that specifies or references the particular cuts of the key to operate a lock.

key coding machine

n. a key machine designed for the production of code keys. It may or may not also serve as a duplicating machine.

key duplicating machine

n. a key machine which is designed to make copies from a pattern key

key gauge

n. a usually flat device with a cutaway portion indexed with a given set of depth or spacing specifications. It is used to help determine the combination of a key.

key interchange

n. an undesirable condition, usually in a master key system, whereby a key unintentionally operates a cylinder or lock

key machine

n. any machine designed to cut keys. See also `key coding machine` and `key duplicating machine.`

key manipulation

n. manipulation of an incorrect key in order to operate a lock or cylinder

key records

n. pl. records which typically include some or all of the following: bitting list, key bitting array, key system schematic, end user, number of keys/cylinders issued, names of persons to whom keys were issued, hardware/keying schedule

key section

n. the exact cross sectional configuration of a key blade as viewed from the bow toward the tip

key symbol

n. a designation used for a key combination in the standard key coding system, e.g., A, AA, AA1, etc.

key system schematic

n. a drawing with blocks utilizing keying symbols, usually illustrating the hierarchy of all keys within a master key system. It indicates the structure and total expansion of the system.

keyed alike

adj. of or pertaining to two or more locks or cylinders which have or are to have the same combination. They may or may not be part of a keying system.

keyed different

adj. of or pertaining to a group of locks or cylinders, each of which is or is to be combinated differently from the others. They may or may not be part of a keying system.

keyed random

adj. of or pertaining to a cylinder or group of cylinders selected from a limited inventory of different key changes. Duplicate bittings may occur.

keyed.

1. adj. combinated 2. having provision for operation by key

keying

n. any specification for how a cylinder or group of cylinders are or are to be combinated in order to control access

keying conference

n. a meeting of the end user and the key system supplier at which the keying and levels of keying, including future expansion, are determined and specified

keying schedule

n. a detailed specification of the keying system listing how all cylinders are to be keyed and the quantities, markings, and shipping instructions of all keys and/or cylinders to be provided

keying symbol

n. a designation used for a lock or cylinder combination in the standard key coding system; e.g., AA1, XAA1, X1X, etc.

keyway

1. n. the opening in a lock or cylinder which is shaped to accept a key bit or blade of a proper configuration 2. the exact cross sectional configuration of a keyway as viewed from the front. It is not necessarily the same as the key section.

keyway grooves

Long narrow milled out areas along the sides of the blade to allow the blade to bypass the wards in the keyway.

KR

1. abb. keyed random 2. abb. key retaining

KWY

abb. keyway

lever lock

lock with levers that are each lifted to the correct level by a bit key or flat metal key to enable the lock to operate.

lower pins

The pins of a lock that contact the cuts on the key. Also called bottom pins.

MACS

abb. maximum adjacent cut specification. MACS exists because of the physical relationship between the spacing of key cuts, the increment between cut depths, and the angle of the cutter. As each of these three factors changes, so does the MACS. That is why the MACS can be different from one manufacturer to another, or even for different cylinder products within the same manufacturer, like Schlage full size keys and small format IC keys.

maid`s master key

n. the master key in a hotel master key system given to the maid. It operates only cylinders of the guest rooms and linen closets in the maid`s designated area.

maison key system

n. [from the French, meaning `house` key system] a keying system in which one or more cylinders are operated by every key (or relatively large numbers of different keys) in the system; e.g., main entrances of apartment buildings operated by all individual suite keys of the building

master key

1. n. a key which operates all the master keyed locks or cylinders in a group, each lock or cylinder usually operated by its own change key 2. v. to combinate a group of locks or cylinders such that each is operated by its own change key as well as by a master key for the entire group

master key system

1. n. any keying arrangement which has two or more levels of keying 2. a keying arrangement which has exactly two levels of keying

master keyed

adj. of or pertaining to a cylinder or group of cylinders which are or are to be combinated so that all may be operated by their own change key(s) and by additional key(s) known as master key(s)

master keyed only

adj. of or pertaining to a lock or cylinder which is or is to be combinated only to a master key

master pin

1. n. usually a cylindrical shaped tumbler, flat on both ends, placed between the top and bottom pin to create an additional shear line 2. a pin tumbler with multiple gates to accept a sidebar

maximum adjacent cut specification (MACS)

n. the maximum allowable difference between adjacent cut depths

MK

abb. master key

MK`d

abb. master keyed

MK`d only

abb. master keyed only

MLAA

Master Locksmith Association of Australia

multi-section key blank

n. a key section which enters more than one, but not all keyways in a multiplex key system

multiplex key blank

n. any key blank which is part of a multiplex key system

multiplex key system

1. n. a series of different key sections which may be used to expand a master key system by repeating bittings on additional key sections. The keys of one key section will not enter the keyway of another key section. This type of system always includes another key section which will enter more than one, or all of the keyways. 2. a keying system which uses such keyways and key sections

NCK

symbol for `no change key,` primarily used in hardware schedules

NMK

a keying symbol which means `not master keyed` and is suffixed in parentheses to the regular key symbol. It indicates that the cylinder is not to be operated by the master key(s) specified in the regular key symbol; e.g., AB6(NMK).

non key retaining

adj. of or pertaining to a lock whose key can be removed in both the locked and unlocked positions

O-bitted

see `zero bitted`

one bitted

adj. of or pertaining to a cylinder which is or is to be combinated to keys cut to the manufacturer`s reference number one bitting.

operating key

n. 1. any key which will properly operate a lock or cylinder to lock or unlock the lock mechanism and is not a control key or reset key

paracentric

1. adj. of or pertaining to a keyway with one or more wards on each side projecting beyond the vertical center line of the keyway to hinder picking 2. of or pertaining to a key blank made to enter such a keyway

pin

v. to install pin tumblers into a cylinder and/or cylinder plug

pin chamber

n. the corresponding hole drilled into the cylinder shell and/or plug to accept the pin(s) and spring

pin stack

n. all the tumblers in a given pin chamber

pin stack height

n. the measurement of a pin stack, often expressed in units of the lock manufacturer`s increment or as an actual dimension

pin tumbler

n. usually a cylindrical shaped tumbler. Three types are normally used: bottom pin, master pin and top pin.

pinning chart

n. a numerical diagram which indicates the sizes and order of installation of the various pins into a cylinder. The sizes are usually indicated by a manufacturer`s reference number which equals the quantity of increments a tumbler represents.

pipe key

A key with a bit projecting from a hollow cylindrical shaft.

plug

n. the part of a cylinder which contains the keyway, with tumbler chambers usually corresponding to those in the cylinder shell

plug follower

n. a tool used to allow removal of the cylinder plug while retaining the top pins, springs, and/or other components within the shell

plug holder

n. a holding fixture which assists in the loading of tumblers into a cylinder plug

progress

v. to select possible key bittings from the key bitting array, usually in numerical order

progression

n. a logical sequence of selecting possible key bittings, usually in numerical order from the key bitting array

progressive

n. any bitting position which is progressed rather than held constant

restricted

adj. of or pertaining to a keyway and corresponding key blank whose sale and/or distribution is limited by the lock manufacturer in order to reduce unauthorized key proliferation

rotating constant

n. one or more cut(s) in a key of any level which remain constant throughout all levels and are identical to the top master key cuts in their corresponding positions. The positions where the top master key cuts are held constant may be moved, always in a logical sequence.

rotating constant method

n. a method used to progress key bittings in a master key system, wherein at least one cut in each key is identical to the corresponding cut in the top master key. The identical cut(s) is moved to different locations in a logical sequence until each possible planned position has been used.

sub-master key

n. the master key level immediately below the master key in a system of six or more levels of keying

stop (of a key)

n. the part of a key from which all cuts are indexed and which determines how far the key enters the keyway

selective key system

n. a key system in which every key has the capability of being a master key. It is normally used for applications requiring a limited number of keys and extensive cross keying.

selective master key

n. an unassociated master key which can be made to operate any specific lock(s) in the entire system in addition to the regular master key(s) and/or change key(s) for the cylinder without creating key interchange

sequence of progression

n. the order in which bitting positions are progressed to obtain change key combinations

set-up key

1. n. a key used to calibrate some types of key machines 2. a key cut to all #9 depths, used to hold Primus finger pins and Everest check pins in place while loading the plug

SFIC

abb. small format interchangeable core

shear line

n. a location in cylinder at which specific tumbler surfaces must be aligned, removing obstruction(s) which prevented the plug from moving

shell

n. the part of the cylinder which surrounds the plug and which usually contains tumbler chambers corresponding to those in the plug

shoulder

The edge of the key that touches the face of the lock to define how far the key is inserted into the lock.

shoulder

n. any key stop other than a tip stop, see also `bow stop`

shove knife

n. a tool used with a set-up plug which pushes the springs and pin tumblers into the cylinder shell

shut out mode

n. the state of a hotel function lockset which prevents operation by all keys except the emergency master key, display key, and some types of shut out keys

sidebar

n. a primary or secondary locking device in a cylinder. When locked, it extends along the plug beyond its circumference. It must enter gates in the tumblers in order to clear the shell and allow the plug to rotate.

simplex key section

n. a single independent key section which cannot be used in a multiplex key system

single key section

n. an individual key section which can be used in a multiplex key system

single step progression

n. a progression using a one increment difference between bittings of a given position

SKD

symbol for `single keyed,` normally followed by a numerical designation in the standard key coding system; e.g., SKD1, SKD2, etc. It indicates that a cylinder or lock is not master keyed but is part of the keying system.

SMK

abb. sub-master key

spacing

n. the dimensions from the stop to the center of the first cut and/or to the centers of successive cuts

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.

spring cover

n. a device for sealing one or more pin chambers

standard key coding system

n. an industry standard and uniform method of designating all keys and/or cylinders in a master key system. The designation automatically indicates the exact function and keying level of each key and/or cylinder in the system, usually without further explanation.

standard progression format

n. a systematic method of listing and relating all change key combinations to all master key combinations in a master key system. The listing is divided into segments known as blocks, horizontal groups, vertical groups, rows, and pages, for levels of control.

two step progression

n. a progression using a two increment difference between bittings of a given position

tumbler

n. a movable obstruction of varying size and configuration in a lock or cylinder which makes direct contact with the key or another tumbler and prevents an incorrect key or torquing device from activating the lock or other mechanism

top pins

The pins in a lock that sit on top of the lower pins.

top master key

The highest level masterkey that fits all the locks in a multi-level masterkeyed system.

TMK

abb. top master key

tip stop

n. a type of stop located at or near the tip of the key

tip

n. the portion of the key which enters the keyway first

theoretical key changes

n. pl. the total possible number of different combinations available for a specific cylinder or lock mechanism

tang

The end of a file where a handle is to be attached.

tailpiece

n. an actuator attached to the rear of the cylinder, parallel to the plug, typically used on rim, key-in-knob or special purpose cylinders

upper pins

The pins in a lock that sit on top of the lower pins.

uncontrolled cross keying

n. a condition in which two or more different keys under different higher level keys operate one cylinder by design; e.g., XAA1 operated by AB, AB1 NOTE: This condition severely limits the security of the cylinder and the maximum expansion of the system, and often leads to key interchange

uncombinated

1. adj. of or pertaining to a cylinder which is or is to be supplied without keys, tumblers and springs 2. of or pertaining to a lock, cylinder or key in which the combination has not been set

unassociated master key

n. a master key which does not have change keys related to its combination through the use of constant cuts

unassociated change key

n. a change key which is not related directly to a particular master key through the use of certain constant cuts

UL

abb. Underwriters Laboratories

VKC

abb. visual key control

visual key control

n. a specification that all keys and the visible portion of the front of all lock cylinders be stamped with standard keying symbols

ward

Protrusions that stick out of the sides of the keyway to allow entry of only the correct type of key blank.

X

symbol used in hardware schedules to indicate a cross keyed condition for a particular cylinder; e.g., XAA2, X1X (but not AX7)

zero bitted

adj. of or pertaining to a cylinder which is or is to be combinated to keys cut to the manufacturer's reference number "0" bitting