CML Keying Systems & Key Control 2 — Questions and Answers
Question 1: In a master key system, what does the term 'cross keying' refer to?
- Keying two locks alike within the same system
- Keying a lock to operate under two or more keys that are not in a hierarchical relationship (Correct answer)
- Creating a key that operates all locks in a grand master system
- Duplicating a key across different key blank series
Correct answer: Keying a lock to operate under two or more keys that are not in a hierarchical relationship
Cross keying allows a lock to be operated by two or more keys that are not master keys of each other, used for shared access areas like restrooms.
Question 2: What is the maximum number of change keys typically possible under a single master key in a standard pin tumbler system using 6 pins?
- 25
- 50
- 100
- 120 (Correct answer)
Correct answer: 120
With 6 pins and standard progression, the theoretical maximum is 120 change keys under a single master key.
Question 3: A 'rotating master key system' is primarily used to:
- Allow a single key to open all locks in sequence
- Periodically change the master key without rekeying individual locks (Correct answer)
- Rotate the master pins within the lock cylinder
- Enable temporary access that expires automatically
Correct answer: Periodically change the master key without rekeying individual locks
A rotating master key system allows the master key to be changed periodically for security reasons without the need to rekey every lock in the system.
Question 4: What is a 'key section' in the context of key control?
- The bow (head) of the key
- The unique profile or cross-sectional shape of the key blade that restricts duplication to authorized dealers (Correct answer)
- The cut pattern on the key blade
- The tip of the key that enters the keyway first
Correct answer: The unique profile or cross-sectional shape of the key blade that restricts duplication to authorized dealers
The key section is the cross-sectional profile of the key blade that matches a specific keyway, and proprietary sections help restrict unauthorized key duplication.
Question 5: In a master key system, a 'maison keying' arrangement is most commonly found in:
- Corporate office buildings
- Residential apartment complexes (Correct answer)
- Government facilities
- Hospital operating rooms
Correct answer: Residential apartment complexes
Maison keying is used in apartment buildings where each tenant's key opens their own unit plus common areas, while the master key opens all units.
Question 6: When should a locksmith refuse to add a new key to an existing master key system?
- When the system already has more than 20 keys
- When adding the key would require cross keying that compromises security (Correct answer)
- When the customer requests a restricted key blank
- When the system uses more than 4 pin chambers
Correct answer: When adding the key would require cross keying that compromises security
Adding a key that requires cross keying can create security vulnerabilities by allowing unintended cross-access between otherwise separate keyways.
Question 7: What does the term 'key differ' mean in a master key system?
- The physical difference between a master key and a change key
- Each unique cut combination assigned to an individual lock in the system (Correct answer)
- The tolerance variation between cuts on duplicate keys
- The difference in depth between the highest and lowest cuts on a key
Correct answer: Each unique cut combination assigned to an individual lock in the system
A key differ (or 'differ') is the unique bitting combination assigned to each individual lock in a master key system to distinguish it from other locks.
CML Keying Systems & Key Control 2
In a master key system, what does the term 'cross keying' refer to?