Pin Tumbler & Cylinder Mechanisms Flashcards
7 cards from real CPL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pin Tumbler & Cylinder Mechanisms flashcards as text
What is 'key control' as it relates to pin tumbler cylinders?
Answer: Limiting who can duplicate keys by using patented or restricted keyways
Key control refers to restricting unauthorized key duplication, typically through patented keyways, restricted blanks, or high-security cylinders.
When rekeying a pin tumbler lock, which set of pins is typically replaced?
Answer: Key pins (bottom pins) to match the new key bitting
Rekeying involves replacing the key pins with new ones of different heights so the lock operates only with the new key.
A 'false set' during picking occurs when:
Answer: The plug rotates slightly because some pins are set but at least one driver pin still blocks
A false set happens when enough pins are set to allow slight plug rotation, but at least one driver pin is still crossing the shear line, preventing full rotation.
What is the function of the plug follower in cylinder servicing?
Answer: To hold the driver pins in place while the plug is removed, preventing them from falling
The plug follower is inserted behind the plug as it is removed, maintaining pressure on driver pins and springs so they do not fall out of the shell.
Which measurement system is most commonly used in the US to specify pin tumbler key cut depths?
Answer: Numeric depth codes assigned by the manufacturer
US lock manufacturers assign numeric depth codes (e.g., 1–9) to represent specific cut depths, making it easier to reference bitting without precise measurements.
What does 'MACS' (Maximum Adjacent Cut Specification) govern in key cutting?
Answer: The largest allowable depth difference between any two adjacent key cuts
MACS defines the greatest permitted depth difference between neighboring cuts on a key; exceeding MACS can prevent the key from operating the lock or damage the cylinder.
In a high-security pin tumbler cylinder, sidebar mechanisms provide additional security by:
Answer: Requiring an additional set of elements (sidebar pins or sliders) to align before the plug rotates
Sidebar cylinders add a secondary locking element (the sidebar) that must retract—by aligning sidebar pins or sliders—before the plug can rotate, defeating standard picking.