CML Lock Mechanisms & Hardware 4 — Questions and Answers
Question 1: What is a 'master wafer' (or master disc) in a master-keyed pin tumbler lock?
- An oversized driver pin used only in master key systems
- An extra pin segment added to a pin stack to create an additional shear line for a master key (Correct answer)
- A wafer that replaces a driver pin when masterkeying a wafer lock
- A special key blank used only by locksmiths for master key systems
Correct answer: An extra pin segment added to a pin stack to create an additional shear line for a master key
A master wafer (also called master pin) is a thin pin segment inserted into a pin stack to create a second shear line, allowing both the change key and the master key to operate the cylinder.
Question 2: What is the purpose of a 'key control' system in a commercial facility?
- To electronically log every key use with a timestamp
- To restrict unauthorized duplication of keys through patented keyways and registered key blanks (Correct answer)
- To allow one master key to open all locks in a building
- To automatically rekey locks when an employee leaves
Correct answer: To restrict unauthorized duplication of keys through patented keyways and registered key blanks
Key control systems use proprietary, patented keyways and registered key blanks that cannot be legally duplicated without authorization, controlling who can obtain additional copies.
Question 3: A locksmith is working with a Schlage B-series deadbolt. What is the standard throw length of this bolt?
- 1/2 inch
- 5/8 inch
- 1 inch (Correct answer)
- 1-1/2 inches
Correct answer: 1 inch
Standard residential and light commercial deadbolts, including the Schlage B-series, have a 1-inch bolt throw, which is the minimum recommended by most security standards.
Question 4: Which mechanism in a high-security padlock is designed to protect against bolt-cutter attacks?
- A hardened steel shackle with boron or chromium alloy (Correct answer)
- A secondary locking lug on the shackle
- A case-hardened steel body plate
- An anti-pick sidebar in the cylinder
Correct answer: A hardened steel shackle with boron or chromium alloy
High-security padlocks use shackles made from hardened boron alloy or chrome-moly steel, which is significantly harder than standard steel and resists cutting with bolt cutters.
Question 5: What is 'mushroom pinning' and why is it used?
- A technique using mushroom-shaped driver pins to increase resistance to picking by creating false sets (Correct answer)
- A method of masterkeying that uses multiple master wafers in one pin stack
- A way of increasing a lock's key bitting depth range
- A type of spring used in high-cycle commercial locks
Correct answer: A technique using mushroom-shaped driver pins to increase resistance to picking by creating false sets
Mushroom (or spool) pins have a shaped profile that creates a 'false set' during picking attempts, causing the plug to partially rotate and then bind again, frustrating standard single-pin picking.
Question 6: In a lever tumbler lock (common in safe deposit boxes), what is the 'fence'?
- The metal guard that prevents forced entry into the lock case
- A projection on the bolt that must align with the gates of all levers before the bolt can move (Correct answer)
- The warding that restricts which keys can enter the keyway
- The post that the lever springs press against
Correct answer: A projection on the bolt that must align with the gates of all levers before the bolt can move
The fence is a projection on the lock bolt that must align with the gate (notch) in every lever simultaneously; when all levers are lifted to the correct height by the key, the fence passes through and the bolt can move.
Question 7: What is the function of an 'anti-drill plate' or 'hard plate' in a lock?
- To protect the plug face from rotational drilling attacks
- To protect critical lock components from drill bits by deflecting or destroying the drill tip (Correct answer)
- To prevent the entire lock body from being punched through the door
- To reinforce the strike plate against kick-in attacks
Correct answer: To protect critical lock components from drill bits by deflecting or destroying the drill tip
An anti-drill (hard) plate is a layer of case-hardened steel or carbide material placed over critical components that spins or breaks drill bits, protecting the lock's internal mechanism from drill attacks.
CML Lock Mechanisms & Hardware 4
What is a 'master wafer' (or master disc) in a master-keyed pin tumbler lock?