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ALOA CML practice questions

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Question 1Locksmithing Fundamentals and Practical Skills

Which type of key cut uses a rotating cutter wheel to remove material from the blade edge, producing a key that operates a pin tumbler cylinder?

  1. Lever lock key
  2. Bit key
  3. Tubular key
  4. Cylinder key Correct answer.

Explanation

Cylinder keys are cut on the edge of the blade to match the pin heights in a pin tumbler cylinder. The bitting profile is read along the blade edge. Bit keys and lever keys use a different mechanism and are cut differently.

Question 2Locksmithing Fundamentals and Practical Skills

A pin tumbler cylinder has five pins and the key is cut to the deepest possible bitting on every position. What is the primary effect on the lock?

  1. The plug will rotate freely
  2. The shear line will not align Correct answer.
  3. The key will not enter the keyway
  4. The springs will bind

Explanation

Deep cuts leave the bottom pins low, so the tops of the pins do not reach the shear line simultaneously. The shear line must align across all chambers for the plug to turn. A key with all deep cuts cannot lift each pin to the correct height.

Question 3Locksmithing Fundamentals and Practical Skills

What is the standard purpose of a plug follower when servicing a pin tumbler cylinder?

  1. To cut a new key
  2. To measure pin lengths
  3. To hold the driver pins and springs in place as the plug is removed Correct answer.
  4. To align the cylinder in a vise

Explanation

A follower is inserted behind the plug as it is withdrawn, keeping the springs and driver pins captured in the Bible. Without a follower, the springs and drivers would eject. It does not measure or cut anything.

Question 4Locksmithing Fundamentals and Practical Skills

Which tool is used to measure the depth of a key cut against a reference bitting?

  1. Plug spinner
  2. Tension wrench
  3. Depth gauge Correct answer.
  4. Pick gun

Explanation

A depth gauge measures the height or depth of each cut so it can be compared to a reference. Tension wrenches, plug spinners, and pick guns are lock manipulation tools, not measuring tools. Accurate measurement is essential for duplicating or originating keys.

Question 5Locksmithing Fundamentals and Practical Skills

In a pin tumbler lock, what component sits between the driver pin and the plug?

  1. The tailpiece
  2. The key pin (bottom pin) Correct answer.
  3. The cam
  4. The Bible

Explanation

The bottom pin, also called the key pin, rests directly on the key and is pushed upward by the bitting. The driver pin sits above it and is pushed by the spring. The cam and tailpiece are external hardware.

Question 6Locksmithing Fundamentals and Practical Skills

Which of the following best describes the function of the keyway warding in a lock?

  1. It sets the pin heights
  2. It restricts which key blanks can enter Correct answer.
  3. It holds the springs
  4. It retains the plug

Explanation

Warding is the pattern of ridges and grooves in the keyway that must match the key blade profile. It prevents unauthorized blanks from entering the cylinder. Warding does not affect pin heights or hold the plug or springs.

Question 7Locksmithing Fundamentals and Practical Skills

What is the primary purpose of a mortise lock body's faceplate?

  1. To hold the cylinder
  2. To align the door hinges
  3. To store spare keys
  4. To cover the lock body and provide the bolt opening Correct answer.

Explanation

The faceplate is mounted on the edge of the door and covers the lock body, with openings for the latch and deadbolt. It protects the mechanism and provides the finished edge. It does not hold the cylinder or store keys.

Question 8Locksmithing Fundamentals and Practical Skills

Which key blank feature must match the lock's keyway to allow insertion?

  1. The key length only
  2. The bow shape
  3. The blade profile and groove pattern Correct answer.
  4. The key color

Explanation

The blade profile, including grooves and warding, must match the keyway to allow the key to enter. The bow shape and color are cosmetic. Blade length alone does not ensure a match.

Question 9Locksmithing Fundamentals and Practical Skills

A locksmith is duplicating a key and notices the original is slightly worn, producing shallow cuts. What is the best practice before cutting the duplicate?

  1. Use a deeper cutter setting to compensate
  2. Measure the original with calipers and cut to the correct bitting Correct answer.
  3. Grind the original key first
  4. Cut the duplicate to match the worn key exactly

Explanation

Worn keys can produce inaccurate duplicates, so measuring the original and referencing the correct bitting yields a reliable key. Copying a worn key propagates the error. Adjusting cutter depth arbitrarily or grinding the original risks further damage.

Question 10Locksmithing Fundamentals and Practical Skills

When picking a pin tumbler lock, why is light tension preferred over heavy tension?

  1. Heavy tension prevents the key from turning
  2. Heavy tension wears the springs
  3. Light tension disables the driver pins
  4. Light tension allows pins to set at the shear line without binding excessively Correct answer.

Explanation

Light tension allows individual pins to bind and set at the shear line one at a time. Excessive tension can cause pins to bind too hard or overset. Tension does not disable driver pins or directly wear springs.

Question 11Locksmithing Fundamentals and Practical Skills

A customer's deadbolt turns but the door will not open. Which is the most likely cause to check first?

  1. The keyway is blocked
  2. The cylinder pins are worn
  3. The springs are weak
  4. The strike plate is misaligned with the bolt Correct answer.

Explanation

If the bolt retracts but the door still will not open, the bolt may be catching on a misaligned strike plate or the door may be swollen. Cylinder or spring issues would typically prevent the bolt from turning. Checking strike alignment is the first practical step.

Question 12Locksmithing Fundamentals and Practical Skills

What does the term 'backset' refer to on a cylindrical lockset?

  1. The depth of the key cut
  2. The length of the latch bolt
  3. The distance from the door edge to the center of the cylinder or spindle hole Correct answer.
  4. The thickness of the door

Explanation

Backset is measured from the edge of the door to the centerline of the bore or latch face. It determines whether standard or drive-in latches will align. It is unrelated to key cuts, door thickness, or bolt length alone.

Question 13Locksmithing Fundamentals and Practical Skills

A locksmith is rekeying a cylinder and finds a pin stack with a driver pin that is too short, leaving a gap. What is the consequence?

  1. The key will not insert
  2. The pin may not reach the shear line properly Correct answer.
  3. The plug will not turn at all
  4. The spring will break

Explanation

Driver pins must be long enough to sit above the shear line when the correct key is inserted. If too short, the pin stack may not align correctly and the lock may not operate reliably. The key can still insert, and the spring is not directly affected.

Question 14Locksmithing Fundamentals and Practical Skills

Which practice best prevents a key from being cut with the wrong bitting spacing?

  1. Calibrating the key machine and using the correct spacing card Correct answer.
  2. Ignoring the shoulder stop
  3. Cutting quickly
  4. Using a worn cutter

Explanation

Key machines must be calibrated and set to the correct spacing for the key blank. Using the wrong spacing card or misaligned machine produces keys that will not operate the lock. Speed and cutter wear can also cause errors.

Question 15Locksmithing Fundamentals and Practical Skills

What is the function of a cylinder's tailpiece (cam) in a mortise lock?

  1. To seal the cylinder
  2. To hold the keyway
  3. To retain the pins
  4. To transfer rotation from the plug to the lock mechanism Correct answer.

Explanation

The tailpiece or cam is attached to the back of the plug and transmits rotation to the locking mechanism. It does not retain pins or form the keyway. Its shape must match the lock body it serves.

Question 16Locksmithing Fundamentals and Practical Skills

When impressioning a key for a pin tumbler lock, what does the presence of a small mark on a cut indicate?

  1. The lock is broken
  2. The key is finished
  3. The pin is binding and the cut needs adjustment Correct answer.
  4. The cut is too deep

Explanation

Impressioning relies on reading marks left by binding pins. A mark indicates where a pin contacts the blade, guiding the locksmith to adjust that cut. Marks do not mean the cut is too deep or the lock is broken.

Question 17Locksmithing Fundamentals and Practical Skills

Which factor most directly determines the number of possible key combinations for a pin tumbler lock?

  1. The number of pins and the number of available cut depths Correct answer.
  2. The color of the key bow
  3. The length of the key blade
  4. The size of the key ring

Explanation

Combinations equal the number of cut depths raised to the number of pin positions. More pins and more depths increase the possible combinations. Bow color, blade length, and key ring size do not affect combinations.

Question 18Locksmithing Fundamentals and Practical Skills

A locksmith is installing a deadbolt and the bolt does not fully extend into the strike. What is the most appropriate correction?

  1. Increase the door thickness
  2. Replace the cylinder
  3. Shorten the bolt
  4. Adjust or replace the strike plate to align with the bolt Correct answer.

Explanation

The strike plate must align with the extended bolt so it seats fully. Adjusting or replacing the strike, or repositioning it, corrects the misalignment. Replacing the cylinder or shortening the bolt does not address alignment.

Question 19Locksmithing Fundamentals and Practical Skills

What is the purpose of a shear line in a pin tumbler lock?

  1. To guide the key into the keyway
  2. To hold the key in place
  3. To separate the plug from the Bible and allow rotation when pins align Correct answer.
  4. To retain the springs

Explanation

The shear line is the boundary between the plug and the Bible. When all pin breaks align at this line, the plug can rotate. It does not hold the key or retain springs.

Question 20Locksmithing Fundamentals and Practical Skills

Which of the following is the best reason to use a torque wrench when tightening cylinder retaining screws?

  1. To increase key cut depth
  2. To align the keyway
  3. To avoid stripping threads or cracking the cylinder Correct answer.
  4. To measure backset

Explanation

Controlled torque prevents over-tightening, which can strip threads or crack the cylinder housing. It does not affect key cuts, keyway alignment, or backset measurement. Proper torque preserves the hardware.

Question 21Locksmithing Fundamentals and Practical Skills

A locksmith encounters a lock with a 'master keyed' cylinder. What does this arrangement allow?

  1. The lock cannot be rekeyed
  2. Only one key operates the lock
  3. The keyway is universal
  4. Two different keys can operate the same cylinder at different pin levels Correct answer.

Explanation

Master keying uses additional pins so that a change key and a master key each set the pin stacks to the shear line at different heights. This allows controlled access at multiple levels. It does not prevent rekeying or create a universal keyway.

Question 22Locksmithing Fundamentals and Practical Skills

When servicing a cylinder, a locksmith finds the plug binds after reassembly. Which is the most likely cause?

  1. The springs are too short
  2. The pins were installed in the wrong order or a driver pin is in a bottom chamber Correct answer.
  3. The key is too long
  4. The cam is painted

Explanation

Binding after reassembly commonly results from incorrect pin order, such as a driver pin placed in a bottom chamber or a missing pin. The pin stack heights then fail to align at the shear line. Key length and spring length are less likely causes.

Question 23Locksmithing Fundamentals and Practical Skills

What is the effect of using a key with a cut that is deeper than the correct bitting on one pin position?

  1. That pin will be overset above the shear line Correct answer.
  2. That pin will not be lifted at all
  3. The plug will rotate freely
  4. The spring will eject

Explanation

A deeper-than-correct cut allows the pin stack to rise higher than intended, pushing the break above the shear line (overset). The pin is lifted, not left down, and the plug will not turn freely because alignment fails.

Question 24Locksmithing Fundamentals and Practical Skills

A locksmith is asked to increase the security of an existing pin tumbler lock without replacing it. Which measure is most effective?

  1. Polishing the key
  2. Increasing the spring tension
  3. Installing security pins and a restricted keyway Correct answer.
  4. Adding a second key ring

Explanation

Security pins (such as spool or serrated pins) and restricted keyways raise picking resistance and control key duplication. Cosmetic changes and spring tension adjustments do not meaningfully improve security.

Question 25Locksmithing Fundamentals and Practical Skills

In a lever lock, what determines the number of possible key combinations?

  1. The finish of the lock
  2. The length of the spindle
  3. The number of levers and the number of gate heights Correct answer.
  4. The size of the key bow

Explanation

Lever lock combinations depend on the number of levers and the available gate heights cut into each lever. More levers and more gate positions increase combinations. Bow size, finish, and spindle length do not affect combinations.

Question 26Locksmithing Fundamentals and Practical Skills

Which hand tool is specifically designed to hold a cylinder plug securely while pins are loaded or removed?

  1. Cylinder vise Correct answer.
  2. Tension wrench
  3. Plug spinner
  4. Plug follower

Explanation

A cylinder vise (plug holder) clamps the plug so the pin chambers stay aligned and pins do not spill during servicing. A follower is used to push the plug out while keeping the chambers plugged, not to clamp the plug.

Question 27Locksmithing Fundamentals and Practical Skills

A locksmith is handed a key and asked to determine its bitting by reading the cuts. Which tool measures the depth of each cut most directly?

  1. Micrometer
  2. Depth key
  3. Key gauge Correct answer.
  4. Feeler gauge

Explanation

A key gauge (bitting gauge) has slots or a scale that reads cut depth against the system's root depths. Depth keys are reference keys for setting a key machine, not measuring an unknown key.

Question 28Locksmithing Fundamentals and Practical Skills

What is the primary function of a lock's strike plate?

  1. To reinforce the jamb where the bolt or latch enters Correct answer.
  2. To limit how far the bolt can retract
  3. To conceal the cylinder from view
  4. To align the door within the frame

Explanation

The strike is mounted on the jamb and receives the bolt or latch, reinforcing the opening against force. It also helps alignment, but its primary security role is to protect the jamb at the bolt entry point.

Question 29Locksmithing Fundamentals and Practical Skills

Which of the following correctly describes the 'handing' of a lock?

  1. The direction a door swings and which side the hinges are on Correct answer.
  2. The finish applied to the lock hardware
  3. The keyway profile cut into the plug
  4. The number of pins in the cylinder

Explanation

Handing refers to whether a door is left- or right-handed based on swing direction and hinge side, which determines whether a handed lock or lever will install correctly. Non-handed hardware works on either side.

Question 30Locksmithing Fundamentals and Practical Skills

A locksmith is installing a cylindrical lockset and the latch bolt must be reversed to match the door swing. What is the correct approach?

  1. Replace the lockset with a handed model
  2. Install the lockset upside down to change the bevel
  3. Pull the latch bolt out and rotate it 180 degrees per the manufacturer's instructions Correct answer.
  4. File the bevel off the latch so it works in either direction

Explanation

Most cylindrical latch bolts are reversible by pulling the bolt and rotating it so the bevel faces the closing direction. This is done per the manufacturer's procedure without modifying the bolt.

Question 31Locksmithing Fundamentals and Practical Skills

When drilling a door for a new cylindrical lockset, what is the purpose of the cross-bore hole?

  1. To house the cylinder only
  2. To allow the latch and chassis to pass through the door thickness Correct answer.
  3. To mount the strike plate
  4. To provide a path for the key

Explanation

The large cross-bore runs through the door face to face so the latch body and lock chassis can be inserted and connected. The smaller edge bore intersects it to accept the latch face.

Question 32Locksmithing Fundamentals and Practical Skills

A locksmith is choosing a drill bit for hardened steel in a lock body. Which bit type is most appropriate?

  1. Wood spade bit
  2. High-speed steel brad-point bit
  3. Cobalt or carbide-tipped bit Correct answer.
  4. Masonry bit

Explanation

Cobalt or carbide-tipped bits retain hardness at higher temperatures and can cut hardened steel. Standard high-speed steel may dull or fail on hardened components.

Question 33Locksmithing Fundamentals and Practical Skills

What does 'pin stacking' refer to when servicing a pin tumbler cylinder?

  1. The technique of using a follower to push pins
  2. The order and combination of pins placed in each chamber Correct answer.
  3. The process of adding extra pins to increase security
  4. The method of aligning the plug to the housing

Explanation

Pin stacking is the specific arrangement of bottom pins, master pins, and driver pins in each chamber to achieve the intended keying. Correct stacking is essential for the cylinder to function at the shear line.

Question 34Locksmithing Fundamentals and Practical Skills

A locksmith is rekeying a cylinder to a new key and finds the new key binds when inserted. Which cause should be checked first?

  1. The plug is too short
  2. The keyway warding does not match the blank Correct answer.
  3. The springs are too weak
  4. The tailpiece is misaligned

Explanation

If a key binds on insertion, the blank's warding or profile may not match the plug keyway. Checking that the correct blank and keyway are used is the first step before disassembly.

Question 35Locksmithing Fundamentals and Practical Skills

When using a plug follower to remove a plug, what is the correct technique?

  1. Keep the follower in contact with the plug as it is pushed out Correct answer.
  2. Insert the follower from the front of the plug
  3. Use the follower to push the springs out first
  4. Remove the follower after each chamber to check pins

Explanation

The follower must stay flush against the rear of the plug as it exits so it plugs each chamber in turn and prevents pins and springs from escaping. Any gap allows pins to drop out.

Question 36Locksmithing Fundamentals and Practical Skills

A locksmith is asked to identify why a rim cylinder will not turn even with the correct key. Which component should be examined for a common cause?

  1. The strike plate screws
  2. The cylinder's tailpiece connection to the lock body Correct answer.
  3. The hinge pins
  4. The door closer arm

Explanation

A rim cylinder drives the lock body through its tailpiece, so a loose, misaligned, or disconnected tailpiece prevents the bolt from operating even when the plug turns. Checking that connection isolates the cylinder from the lock body.

Question 37Locksmithing Fundamentals and Practical Skills

Which property of a key blank ensures the cut key will operate the lock rather than merely fit into the keyway?

  1. The thickness of the key ring hole
  2. The color of the blank's bow
  3. The blank's shoulder-to-tip length and bitting reference Correct answer.
  4. The hardness of the bow

Explanation

Correct reference points-shoulder or tip stop and overall blade length-position the cuts at the right spacing so they align with the pin chambers. A blank that fits but has wrong reference points will not operate the lock.

Question 38Locksmithing Fundamentals and Practical Skills

A locksmith is setting up a key machine and must ensure cuts are the correct depth. Which step is most important before cutting customer keys?

  1. Changing the key clamp to a larger size
  2. Calibrating the machine with a depth key and verifying the cutter Correct answer.
  3. Polishing the cutter with oil
  4. Increasing the machine's cutting speed

Explanation

Calibration with a depth key confirms the machine's depth settings match the system's root depths, and checking the cutter ensures clean, accurate cuts. Skipping calibration produces keys that are consistently too shallow or too deep.

Question 39Locksmithing Fundamentals and Practical Skills

A locksmith is diagnosing a deadbolt that extends but does not seat fully into the strike. Which combination best addresses the root cause?

  1. Lubricate the hinges and adjust the closer
  2. Check door alignment, strike position, and bolt throw Correct answer.
  3. Increase spring tension and replace the cylinder
  4. Replace the thumbturn and rekey the cylinder

Explanation

A bolt that extends but does not seat usually indicates misalignment between the bolt and strike, insufficient bolt throw, or a shifted door. Adjusting strike position and door alignment addresses the mechanical fit.

Question 40Locksmithing Fundamentals and Practical Skills

A locksmith is selecting fasteners for mounting a strike plate to a wood jamb. Which choice best improves resistance to forced entry?

  1. Adhesive only
  2. Nails instead of screws
  3. Short drywall screws into the jamb face
  4. Long screws that reach the wall framing behind the jamb Correct answer.

Explanation

Long screws that penetrate the structural framing transfer force into the wall rather than relying on the jamb alone. Short fasteners can pull out of the jamb under impact.

Question 41Mechanical and Electronic Lock Servicing

A cylindrical lock's latchbolt is beveled so that the door latches when closed. Which component normally retracts the latchbolt when the inside knob is turned?

  1. The strike plate lip
  2. The deadlocking plunger
  3. The retractor assembly acting on the latchbolt tailpiece Correct answer.
  4. The cylinder cam

Explanation

The knob or lever connects to a retractor that pulls the latchbolt tailpiece into the lock body. The strike and plunger affect latching and security, not knob-driven retraction.

Question 42Mechanical and Electronic Lock Servicing

Which keyway feature determines the profile that a key blank must match to enter the plug?

  1. The bitting depth
  2. The keyway groove pattern Correct answer.
  3. The cam rotation angle
  4. The spring tension

Explanation

The keyway is the shaped slot in the plug; its ward and groove pattern must match the blank's profile. Bitting determines how far pins are raised, not whether the blank enters.

Question 43Mechanical and Electronic Lock Servicing

In a pin tumbler cylinder, what is the function of the driver (top) pins?

  1. They align the plug with the shell after turning
  2. They retain the cylinder in the mortise
  3. They sit in the plug bores and contact the key directly
  4. They are pushed by springs to block the shear line until the correct key raises them Correct answer.

Explanation

Driver pins sit above the key pins and are spring-loaded so they straddle the shear line unless the correct key raises each stack to the proper height. The key pins, not the drivers, contact the key.

Question 44Mechanical and Electronic Lock Servicing

A door with a closer slams hard and the latchbolt does not fully engage the strike. Which adjustment is most appropriate first?

  1. Increase the closer's sweep speed
  2. Remove the strike plate entirely
  3. Reduce the closer's latching speed and check the strike alignment Correct answer.
  4. Replace the latchbolt with a longer throw

Explanation

Excess latching speed causes slam and bounce that prevents the bolt from seating. Slowing the latch speed and aligning the strike lets the bolt enter cleanly.

Question 45Mechanical and Electronic Lock Servicing

What is the primary purpose of a mortise lock faceplate?

  1. To deadlock the auxiliary bolt
  2. To transfer motion from the thumbturn
  3. To cover the lock body opening and provide a finished edge at the door's lock stile Correct answer.
  4. To hold the cylinder in the plug

Explanation

The faceplate finishes the mortise cavity and protects the lock body at the door edge. It is not a functional linkage for the cylinder or bolt.

Question 46Mechanical and Electronic Lock Servicing

Which tool is used to measure the depth of a key cut relative to the blade shoulder?

  1. Tension wrench
  2. Pin kit
  3. Plug follower
  4. Depth key or caliper Correct answer.

Explanation

Cut depth is measured with a depth key or caliper referenced to the shoulder. The other tools serve disassembly or picking, not measurement.

Question 47Mechanical and Electronic Lock Servicing

A rim cylinder is mounted to a door by which common method?

  1. A setscrew in the rose
  2. Two mounting screws through the door into the cylinder housing Correct answer.
  3. A tailpiece threaded into the lock case
  4. A spring clip on the plug

Explanation

Rim cylinders are typically fastened with two screws through the door into the cylinder body, with a tailpiece engaging the lock. The tailpiece transmits motion but does not mount the cylinder.

Question 48Mechanical and Electronic Lock Servicing

What does the term 'backset' describe on a lockset?

  1. Thickness of the door
  2. Distance from the door edge to the center of the cylinder or spindle hole Correct answer.
  3. Width of the faceplate
  4. Length of the latchbolt throw

Explanation

Backset is measured from the door edge (or faceplate) to the centerline of the bore. It determines whether a replacement lockset will align with existing holes.

Question 49Mechanical and Electronic Lock Servicing

During rekeying, a technician finds that a key pin sits above the shear line with the correct key inserted. What is the most likely cause?

  1. The spring is too weak
  2. The driver pin is too short
  3. The key pin is too long for that chamber Correct answer.
  4. The plug is rotated 180 degrees

Explanation

If the key pin protrudes above the shear line, the stack is too tall for the cut depth, indicating an overlong key pin. Replacing it with the correct length restores the shear line.

Question 50Mechanical and Electronic Lock Servicing

A master-keyed pin tumbler cylinder uses which arrangement to allow two different keys to operate it?

  1. A wider keyway accepting both blades
  2. Two plugs sharing one cam
  3. A single pin with a tapered bottom
  4. Split pins that create two shear points Correct answer.

Explanation

Master keying uses split (master) pins so that the change key aligns one shear point and the master key aligns another. The plug and keyway remain single.