Free CRL Lock Installation & Repair Questions and Answers — Questions and Answers
Question 1: Which of the following is the most appropriate tool for mortising a door for lock installation?
- Screwdriver
- Mortising jig (Correct answer)
- Wood chisel
- Auger bit
Correct answer: Mortising jig
A mortising jig is the most appropriate tool for mortising a door for lock installation because it provides a precise and consistent template. This specialized tool guides a router or chisel, ensuring that the mortise (the recess for the lock body) is cut to the exact dimensions and depth required for a secure and flush fit. While a wood chisel can be used, a jig significantly improves accuracy and efficiency, especially for professional installations.
Question 2: What is the standard backset measurement for most residential locksets?
- 2 inches
- 2-3/4 inches (Correct answer)
- 3 inches
- 3-1/4 inches
Correct answer: 2-3/4 inches
The standard backset measurement for most residential locksets in North America is 2-3/4 inches (70 mm). This measurement refers to the distance from the edge of the door to the center of the bore hole where the lock cylinder or spindle passes through. While 2-3/8 inches is also common, 2-3/4 inches is widely considered the most prevalent standard for exterior and interior residential doors.
Question 3: When installing a deadbolt, what should be checked to ensure smooth operation?
- Strike plate alignment (Correct answer)
- Color of the bolt
- Door paint finish
- Doorknob tension
Correct answer: Strike plate alignment
When installing a deadbolt, checking the strike plate alignment is critical to ensure smooth and proper operation. The strike plate is the metal plate installed on the door frame that the deadbolt extends into. If it's misaligned, the bolt may bind, not fully extend, or fail to engage securely, compromising the lock's function and security.
Question 4: What is the function of a latch bolt?
- To connect the knob to the lock
- To extend and hold the door shut (Correct answer)
- To guide the key into the cylinder
- To rotate the cylinder
Correct answer: To extend and hold the door shut
The primary function of a latch bolt is to extend from the edge of the door into the strike plate on the door frame, thereby holding the door shut. Unlike a deadbolt, a latch bolt is typically spring-loaded and has an angled face, allowing the door to be closed and latched without needing a key or turning a knob, though it can be retracted by turning a knob or lever.
Question 5: Which component prevents a lock cylinder from being turned without a key?
- Strike plate
- Retainer clip
- Pin tumblers (Correct answer)
- Cam lock
Correct answer: Pin tumblers
Pin tumblers are the crucial components within a lock cylinder that prevent it from being turned without the correct key. These small pins, arranged in sets of driver pins and key pins, must be precisely aligned by the bitting of the correct key to create a shear line. When aligned, the cylinder can rotate, allowing the lock to open; otherwise, the pins block rotation.
Question 6: Which tool is best for removing a broken key from a lock cylinder?
- Lock pick
- Key extractor (Correct answer)
- Screw extractor
- Needle nose pliers
Correct answer: Key extractor
A key extractor is a specialized tool designed specifically for removing broken keys from a lock cylinder. It typically features thin, barbed, or hooked ends that can be inserted into the keyway alongside the broken key fragment. These hooks can then grip the key, allowing it to be carefully pulled out without damaging the lock mechanism.
Question 7: What is the main reason to install a reinforcing strike plate?
- Aesthetic appeal
- Reduce installation time
- Prevent bolt retraction
- Increase door security (Correct answer)
Correct answer: Increase door security
The main reason to install a reinforcing strike plate is to significantly increase door security. Standard strike plates are often thin and secured with short screws, making them vulnerable to forced entry attempts like kicking or prying. A reinforcing strike plate is thicker, extends further into the door frame, and is secured with longer screws, providing much greater resistance against brute force attacks.
Question 8: What is the purpose of a cylinder retaining clip?
- Prevent cylinder rotation
- Secure the cylinder in place (Correct answer)
- Connect cylinder to bolt
- Seal the keyway
Correct answer: Secure the cylinder in place
The purpose of a cylinder retaining clip, often called a C-clip or spring clip, is to secure the lock cylinder firmly within the lock body or door. This clip fits into a groove on the cylinder and against the lock mechanism, preventing the cylinder from being pulled out or pushed through the door. It ensures the cylinder remains stable and functional during operation.
Question 9: Which lock type is most commonly used for securing exterior residential doors?
- Cam lock
- Tumbler lock
- Deadbolt (Correct answer)
- Padlock
Correct answer: Deadbolt
A deadbolt is the lock type most commonly used for securing exterior residential doors due to its superior security features. Unlike a spring-loaded latch bolt, a deadbolt cannot be forced open by prying or shimming because its bolt is solid and has no spring mechanism. This provides a much higher level of resistance against forced entry, making it essential for primary door security.
Free CRL Lock Installation & Repair Questions and Answers
Which of the following is the most appropriate tool for mortising a door for lock installation?