CML Lock Mechanisms & Hardware 5

Question 1

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

Accepted Answer

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

Answer

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.

Question 2

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

Accepted Answer

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

Answer

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.

Question 3

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

Accepted Answer

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

Answer

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.

Question 4

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

Accepted Answer

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

Answer

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.

Question 5

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?

Accepted Answer

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

Answer

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.

(CML) Certified Master Locksmith Practice Test

(CML) Certified Master Locksmith Practice Test

CML Lock Mechanisms & Hardware 5