Lock Mechanisms & Hardware Flashcards

What does 'key bitting array' (KBA) refer to in a master key system?

Answer: The complete set of all possible bitting combinations available in a key system

The key bitting array is the full matrix of all theoretically possible key bittings for a given lock's specifications (depths, cuts, and spaces), from which a master key system designer selects combinations.

What is a 'mogul' cylinder and where is it typically used?

Answer: An oversized cylinder (1-1/2" diameter or larger) used in high-traffic institutional or government applications

Mogul cylinders have a larger-than-standard diameter (typically 1-1/2 inches or greater) and are used in high-security government, institutional, and transit applications requiring increased key control and durability.

In a disc detainer lock, what replaces the pin tumblers as the blocking mechanism?

Answer: Rotating discs with slots that must align to allow the bolt carrier to rotate

Disc detainer locks use a stack of rotating discs, each with a slot cut at a specific angle; the correct key rotates each disc to the right position so all slots align, allowing the core to rotate.

What is the 'total position' (TP) in master key system design?

Answer: The sum of all depth values across all cut positions on a key

Total position (TP) is calculated by adding the depth values of all cuts on a key, and keys in a master key system must maintain minimum and maximum TP differences to ensure they cannot accidentally cross-operate.

A locksmith notices that a commercial door's latch is not catching the strike plate and the door rattles. What hardware component adjustment is FIRST recommended?

Answer: Adjust the strike plate position or install a strike plate with a larger opening

Strike plate misalignment is the most common cause of a latch not catching; adjusting the strike plate position or installing a strike with an oversized opening is the standard first-line correction before modifying the door or lockset.

Which ANSI door hardware function number designates a classroom lock (key locks/unlocks from outside, always free from inside)?

Answer: Function F13

ANSI Function F13 (classroom function) is keyed from the outside only, with the inside lever always free to exit, making it the standard function for school and classroom applications.

What is the purpose of a 'cutout' or 'relief cut' on a key bow or shoulder stop?

Answer: To serve as a depth reference or positive stop that positions the key blade consistently in the cylinder

The shoulder stop (or tip stop on tip-operated systems) is a precise reference point that ensures the key blade seats at the same depth each insertion, guaranteeing consistent alignment of each cut with its corresponding pin stack.