CML Lock Mechanisms & Hardware 3

Question 1

What is the function of the control lug on a removable-core (BEST-type) cylinder?

Accepted Answer

It retracts when the control key is inserted, allowing the core to be removed from the housing

Answer

The control lug engages the housing to retain the core; inserting the control key retracts this lug, allowing the core to be pulled out and replaced without tools.

Question 2

In a wafer tumbler lock, what prevents the plug from rotating when the wrong key is inserted?

Accepted Answer

Wafers that extend into the shell's slots when not lifted to the correct height

Answer

In wafer locks, each spring-loaded wafer protrudes into a groove in the shell; the correct key lifts all wafers flush with the plug's outer diameter, clearing the shell grooves and allowing rotation.

Question 3

A Grade 1 commercial lockset, per ANSI/BHMA standards, is rated for a minimum of how many cycles?

Accepted Answer

500,000 cycles

Answer

ANSI/BHMA Grade 1 is the highest commercial grade and requires the lockset to withstand a minimum of 500,000 operational cycles.

Question 4

What is the main mechanical difference between a mortise lock and a cylindrical (bored) lockset?

Accepted Answer

A mortise lock is a complete locking mechanism housed in a rectangular case mortised into the door edge, while a cylindrical lockset's components mount through bored holes

Answer

A mortise lock body is a self-contained unit inserted into a pocket (mortise) cut into the door edge, whereas a cylindrical lockset is installed through drilled holes in the door face and edge.

Question 5

What does the term 'key cut depth' refer to in key specifications?

Accepted Answer

The vertical distance from the key's shoulder to the lowest point of a given cut

Answer

Key cut depth is the vertical measurement from the key's reference line (shoulder or tip) to the bottom of each individual cut, determining how far each pin is lifted.

(CML) Certified Master Locksmith Practice Test

(CML) Certified Master Locksmith Practice Test

CML Lock Mechanisms & Hardware 3