Locksmith Terms Glossary i-l

• imitation bma: An electro deposited powder or lacquer finish on metal to simulate as nearly as possible the genuine Bronze Metal Antique finish. It is known as lBMA.
• impressioning: A means of fitting a key directly to a locked cylinder by manipulating a blank in the keyway and cutting the blank where the tumlbers have made marks.
• interconnected lockset: A lockset whose trim provides a means of simultaneous retraction of two or more bolts which may also be operated independently.

• jamb: The inside vertical face of a doorway.
• keep or keeper: A term sometimes used, particularly in the North, for a staple or striking plate.

• key change: A term sometimes used instead of “differ”. The change or differ of the key is generally indicated by number, and sometimes numbers and letters marked an the bow.
• 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 steps or key depths: This term usually means the bolt step and lever steps of a key for a lever lock.
• keyway: The part of the plug where you insert the key.
• keyway grooves: Long narrow milled out areas along the sides of the blade to allow the blade to bypass the wards in the keyway.

• latch:A mechanical device which automatically keeps a door closed until a deliberate action is used to retract it.
• latchset:A latch complete with necessary furniture including a spindle, ready for fixing to the door.
• lever handle:A piece of lock or latch furniture, usually on a rose or plate, for use as an alternative to a knob for operating the springbolt of a lock or latch. All British lever handles are spring-loaded to ensure the return to horizontal after use.
• 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.
• lever mechanism:A lock mechanism having, as its principle feature, one or more levers.
• lever pack:A set of lever tumblers.
• lever pivot:The stump in a lock on which the levers swing.
• lever tumbler:Usually a flat, spring-loaded tumbler which pivots on a post.
• link plate:The complementary member of box, desk and other locks which is fixed to the lid or some part of a cabinet, for example, and has one or more projecting links to enter the lock and engage the bolt.
• lip (of striking plate):The projection on one side of a striking plate on the surface of which the springbolt of the lock or latch first strikes when the door is closed.
• lock:Any device which prevents access or use by requiring special knowledge or equipment.
• lockable bolt:A bolt that can be shot and locked in position by the use of a removable key.
• locking latch:A latch with a bevelled springbolt or roller bolt which is capable of being lacked or secured, usually by key.
• lockset:A lock complete with necessary furniture including a spindle, ready for fixing to the door.
• locksmith:A person with the knowledge and ability to select, install, service and bypass all the components of an electrical or mechanical lock.
• London strip:A steel bar fitted to the inside face of a door frame, shaped to accommodate the staple or striker of a rim latch lock.
• long shackle (LS):A padlock shackle with a greater amount of clearance than the normal standard shackle.
• lower pins:The pins of a lock that contact the cuts on the key. Also called bottom pins.
• lubrication:On no account should oil be used to lubricate pin-tumbler cylinders. Graphite is the conventional lubricant for this mechanism.