CPL Pin Tumbler & Cylinder Mechanisms 3

Question 1

What is 'key control' as it relates to pin tumbler cylinders?

Accepted Answer

Limiting who can duplicate keys by using patented or restricted keyways

Answer

Key control refers to restricting unauthorized key duplication, typically through patented keyways, restricted blanks, or high-security cylinders.

Question 2

When rekeying a pin tumbler lock, which set of pins is typically replaced?

Accepted Answer

Key pins (bottom pins) to match the new key bitting

Answer

Rekeying involves replacing the key pins with new ones of different heights so the lock operates only with the new key.

Question 3

A 'false set' during picking occurs when:

Accepted Answer

The plug rotates slightly because some pins are set but at least one driver pin still blocks

Answer

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.

Question 4

What is the function of the plug follower in cylinder servicing?

Accepted Answer

To hold the driver pins in place while the plug is removed, preventing them from falling

Answer

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.

Question 5

Which measurement system is most commonly used in the US to specify pin tumbler key cut depths?

Accepted Answer

Numeric depth codes assigned by the manufacturer

Answer

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.

(CPL) Certified Professional Locksmith Practice Test

(CPL) Certified Professional Locksmith Practice Test

CPL Pin Tumbler & Cylinder Mechanisms 3