Locksmith Test #4 — Questions and Answers

Question 1: A coordinator is necessary for a set of fire doors that:

An overlapping astragal (Correct answer)
Fusible link louvers
An open back strike
Manual flush bolts

Correct answer: An overlapping astragal

A door coordinator is essential for pairs of fire doors that feature an overlapping astragal. The astragal is a strip that covers the gap between the two doors when closed. The coordinator ensures that the inactive door closes first, allowing the active door to close properly and overlap the astragal, which is critical for maintaining the fire rating and sealing the opening effectively.

Question 2: What danger poses the greatest threat while using gas-powered equipment indoors?

Hazardous vapors or fumes (Correct answer)
Temperature of the motor and parts
Corrosiveness of the fuel
Carcinogens in the fuel

Correct answer: Hazardous vapors or fumes

Gas-powered equipment produces exhaust containing dangerous gases like carbon monoxide. When operated indoors without adequate ventilation, these hazardous vapors and fumes can quickly accumulate to toxic levels. Carbon monoxide is colorless and odorless, making it an insidious and potentially fatal threat.

Question 3: Which cutter material normally lasts the longest with proper care?

Cobalt
Carbide (Correct answer)
Carbon steel
High speed steel

Correct answer: Carbide

Carbide, particularly tungsten carbide, is renowned for its extreme hardness, exceptional wear resistance, and ability to withstand high temperatures. These superior properties make carbide cutters significantly more durable and longer-lasting than those made from cobalt, carbon steel, or high-speed steel, especially when maintained with proper care.

Question 4: Many mortise locks employ thru-bolt trim to:

Allow use of either knob or lever trim with the same lock body
Strengthen the installation and minimize binding
Make the installation look better (Correct answer)
Require either a flexible head or concealed shell cylinder

Correct answer: Make the installation look better

Thru-bolt trim for mortise locks involves bolts that pass directly through the lock body, securing the trim (knobs, levers, escutcheons) from one side of the door to the other. While it provides a strong installation, a primary benefit, especially in higher-end applications, is to create a cleaner, more aesthetically pleasing appearance by concealing the mounting screws beneath the trim.

Question 5: How many springs and tumblers are there in a typical 5-cut key cylinder?

3
5 (Correct answer)
8
9

Correct answer: 5

A typical 5-cut key cylinder refers to the number of bitting cuts on the key. Each cut corresponds to a pin stack within the cylinder, which consists of one spring and one tumbler (or pin set, comprising a driver pin and a bottom pin). Therefore, a 5-cut key cylinder will have 5 springs and 5 tumblers to interact with these cuts.

Question 6: Which of the following lock manufacturers is regarded as having "high security" locks?

Kwikset
Master
Medeco (Correct answer)
American

Correct answer: Medeco

Medeco is widely recognized in the locksmith industry for its high-security locks. Their products often feature patented key control, drill resistance, and unique pin tumbler designs that include rotating pins, making them significantly more resistant to picking and unauthorized key duplication compared to standard lock manufacturers.

Question 7: If two adopted references clash, the following reference shall take precedence:

That is adopted by the local jurisdiction
With the more stringent standard (Correct answer)
Used by the AHJ
That is adopted by the OSFM

Correct answer: With the more stringent standard

When two adopted references or standards clash, the principle of 'more stringent' is applied to ensure the highest level of safety and performance. This means that the standard imposing stricter requirements or offering greater protection will take precedence, regardless of which jurisdiction adopted it, to maintain the highest possible safety benchmark.

Question 8: Picking guns involves:

Bouncing the top pins above the shear line (Correct answer)
Clicking all pins above the shear line
Bouncing the bottom pins above the shear line
Crushing the springs

Correct answer: Bouncing the top pins above the shear line

Picking guns, also known as snap guns, work by rapidly striking all the bottom pins simultaneously. This sudden impact causes the top pins to momentarily 'jump' or bounce upwards, creating a brief moment where the shear line is clear. During this fraction of a second, if tension is applied to the plug, the pins can set, allowing the lock to open.

Question 9: A rim cylinder's position is maintained by:

Set screws
The strike plate
A screw in the lock
Two screws from the back of the cylinder (Correct answer)

Correct answer: Two screws from the back of the cylinder

A rim cylinder is designed to be mounted on the surface of a door, typically used with rim-mounted locks or deadbolts. Its position is secured by two screws that pass through the lock body from the interior side of the door and thread directly into the back of the cylinder, holding it firmly in place against the door surface.

Question 10: When picking locks, the tension wrench:

Relieves the spring pressure
Holds the tumblers at the shear line (Correct answer)
Raises the pins to the shear line
Relieves the pressure on the tumblers

Correct answer: Holds the tumblers at the shear line

When picking locks, the tension wrench applies slight rotational pressure to the plug. This pressure is crucial because it creates a binding effect on the pins, allowing each pin to be individually set at the shear line. As each pin is lifted to its correct position, the tension wrench holds it there, preventing it from falling back down and effectively 'setting' the tumblers.

Question 11: What kind of key must typically be copied using an end mill cutter?

Bit
Tubular
Paracentric (Correct answer)
Skeleton

Correct answer: Paracentric

Paracentric keyways have complex, often curved or off-center profiles that make it difficult to insert standard key blanks or manipulate pins with traditional picks. Due to their intricate shape, these keys require specialized cutting machines, typically utilizing an end mill cutter, to accurately reproduce their unique bitting and profile.

Locksmith Test #4

A coordinator is necessary for a set of fire doors that: