Professional Locksmith Certification
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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(Covers Keying Systems, Locks, Safes, Codes, Security Hardware, Electricity
Basics, and General Locksmith Knowledge)
1. Which of the following is the primary function of a pin tumbler lock?
A. To secure electrical systems
B. To align pins at the shear line allowing rotation of the plug
C. To restrict key duplication
D. To control access electronically
Rationale: A pin tumbler lock operates when the key lifts each pin stack to
align the top and bottom pins at the shear line, allowing plug rotation.
,2. What is the purpose of a master pin in a master key system?
A. To increase the security of the lock
B. To create multiple shear lines for different keys
C. To prevent unauthorized key duplication
D. To reduce key wear
Rationale: Master pins divide pin stacks, creating additional shear lines that
allow more than one key to operate the lock.
3. Which keyway type provides the highest restriction for key duplication?
A. Paracentric
B. Yale
C. Restricted keyway
D. Open keyway
Rationale: Restricted keyways are patented and legally controlled to prevent
unauthorized duplication.
4. Which tool is used to remove a cylinder from a mortise lock?
A. Plug follower
B. Shim
C. Cylinder wrench
D. Key extractor
Rationale: A cylinder wrench loosens the cylinder retaining screw, allowing
removal from the mortise body.
,5. The part of the lock that retains the latch bolt in the extended position is
called:
A. Plug
B. Strike plate
C. Spindle
D. Tailpiece
Rationale: The strike plate is mounted on the door frame and holds the latch
bolt when the door is closed.
6. Which pin configuration increases resistance to picking?
A. Standard pins
B. Spool pins
C. Bottom pins
D. Driver pins
Rationale: Spool pins cause a false set during picking, increasing
manipulation difficulty.
7. Which locksmithing term describes the difference between the depths
of adjacent cuts on a key?
A. Increment
B. Step
, C. Bitting
D. Progression
Rationale: The step or increment defines the change in depth between
consecutive key cuts.
8. What is the purpose of the plug follower?
A. To remove the plug from the shell without displacing pins
B. To hold top pins in place during disassembly
C. To align wafers in wafer locks
D. To test shear line smoothness
Rationale: A plug follower pushes out the plug while maintaining pin
position in the shell.
9. What is the first step when rekeying a pin tumbler lock?
A. Remove springs
B. Identify key bitting
C. Remove top pins
D. Lubricate the plug
Rationale: Identifying the key’s bitting ensures correct pinning before
disassembly.
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
(Covers Keying Systems, Locks, Safes, Codes, Security Hardware, Electricity
Basics, and General Locksmith Knowledge)
1. Which of the following is the primary function of a pin tumbler lock?
A. To secure electrical systems
B. To align pins at the shear line allowing rotation of the plug
C. To restrict key duplication
D. To control access electronically
Rationale: A pin tumbler lock operates when the key lifts each pin stack to
align the top and bottom pins at the shear line, allowing plug rotation.
,2. What is the purpose of a master pin in a master key system?
A. To increase the security of the lock
B. To create multiple shear lines for different keys
C. To prevent unauthorized key duplication
D. To reduce key wear
Rationale: Master pins divide pin stacks, creating additional shear lines that
allow more than one key to operate the lock.
3. Which keyway type provides the highest restriction for key duplication?
A. Paracentric
B. Yale
C. Restricted keyway
D. Open keyway
Rationale: Restricted keyways are patented and legally controlled to prevent
unauthorized duplication.
4. Which tool is used to remove a cylinder from a mortise lock?
A. Plug follower
B. Shim
C. Cylinder wrench
D. Key extractor
Rationale: A cylinder wrench loosens the cylinder retaining screw, allowing
removal from the mortise body.
,5. The part of the lock that retains the latch bolt in the extended position is
called:
A. Plug
B. Strike plate
C. Spindle
D. Tailpiece
Rationale: The strike plate is mounted on the door frame and holds the latch
bolt when the door is closed.
6. Which pin configuration increases resistance to picking?
A. Standard pins
B. Spool pins
C. Bottom pins
D. Driver pins
Rationale: Spool pins cause a false set during picking, increasing
manipulation difficulty.
7. Which locksmithing term describes the difference between the depths
of adjacent cuts on a key?
A. Increment
B. Step
, C. Bitting
D. Progression
Rationale: The step or increment defines the change in depth between
consecutive key cuts.
8. What is the purpose of the plug follower?
A. To remove the plug from the shell without displacing pins
B. To hold top pins in place during disassembly
C. To align wafers in wafer locks
D. To test shear line smoothness
Rationale: A plug follower pushes out the plug while maintaining pin
position in the shell.
9. What is the first step when rekeying a pin tumbler lock?
A. Remove springs
B. Identify key bitting
C. Remove top pins
D. Lubricate the plug
Rationale: Identifying the key’s bitting ensures correct pinning before
disassembly.
