Millwright Master Certification Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A precision alignment procedure for a motor and pump using dial
indicators shows a consistent angular misalignment. Which adjustment
is most appropriate to correct this condition while minimizing shaft
stress during operation?
A) Move both machines laterally in the same direction
B) Adjust only the driven machine vertically without rechecking
C) Adjust the machine feet to correct angular offset at the coupling
face
D) Increase coupling bolt torque to force alignment
Correct Answer: C) Adjust the machine feet to correct angular offset at the
coupling face
Angular misalignment is corrected by adjusting machine positioning at the
feet, particularly using shims and jacking bolts, ensuring the coupling faces
become parallel without inducing stress into the shafts or bearings.
2. During vibration analysis of a rotating shaft, a dominant peak at 1×
running speed is observed. What is the most likely mechanical
condition?
A) Bearing outer race defect
, B) Rotor imbalance
C) Gear tooth wear
D) Electrical rotor bar defect
Correct Answer: B) Rotor imbalance
A strong 1× running speed vibration signature typically indicates mass
imbalance in the rotating assembly, causing centrifugal force variations
once per revolution.
3. Which bearing type is most suitable for handling both high radial and
moderate axial loads in a high-speed application?
A) Plain sleeve bearing
B) Tapered roller bearing
C) Deep groove ball bearing
D) Needle roller bearing
Correct Answer: C) Deep groove ball bearing
Deep groove ball bearings are widely used in high-speed applications due
to their ability to support combined radial and moderate axial loads
efficiently with low friction.
4. What is the primary purpose of using a feeler gauge during machinery
setup?
A) Measure shaft diameter
B) Check lubrication viscosity
C) Measure clearance between mating surfaces
D) Determine bolt torque
Correct Answer: C) Measure clearance between mating surfaces
Feeler gauges are precision tools used to measure small gaps or clearances
between components to ensure proper fit and alignment.
5. In a hydraulic system, what does cavitation most commonly indicate?
A) Excessive fluid viscosity
, B) Air contamination or low inlet pressure
C) Overheating of hydraulic oil
D) High return line pressure
Correct Answer: B) Air contamination or low inlet pressure
Cavitation occurs when vapor bubbles form due to low pressure at the
pump inlet, often caused by air leakage or restricted suction flow.
6. Which rigging configuration provides the greatest mechanical
advantage for lifting heavy loads?
A) Single vertical hitch
B) Basket hitch
C) Double choker hitch
D) Straight vertical lift with chain sling
Correct Answer: B) Basket hitch
A basket hitch doubles the load-bearing points under the load, increasing
lifting capacity and stability compared to other sling configurations.
7. What is the primary function of a flexible coupling in rotating
machinery?
A) Increase torque output
B) Compensate for minor misalignment and absorb vibration
C) Reduce electrical load
D) Increase shaft speed
Correct Answer: B) Compensate for minor misalignment and absorb
vibration
Flexible couplings allow limited misalignment between connected shafts
while reducing transmitted vibration and shock loads.
8. Which condition is most indicative of gear backlash problems in a
gearbox?
A) Smooth operation under load
, B) Excessive noise during steady rotation
C) Tight shaft coupling fit
D) High lubricant level
Correct Answer: B) Excessive noise during steady rotation
Excessive backlash causes irregular gear tooth engagement, resulting in
noise, vibration, and potential wear during operation.
9. What is the most accurate method for checking shaft runout in
precision machinery?
A) Steel ruler measurement
B) Dial indicator mounted on a magnetic base
C) Visual inspection only
D) Torque wrench measurement
Correct Answer: B) Dial indicator mounted on a magnetic base
Dial indicators provide highly precise measurement of shaft deviation
during rotation, making them ideal for runout assessment.
10. In preventive maintenance, what is the main advantage of
thermography inspection?
A) Measures electrical resistance
B) Detects temperature anomalies indicating potential failure
C) Measures shaft alignment
D) Replaces lubrication analysis
Correct Answer: B) Detects temperature anomalies indicating potential
failure
Thermography identifies abnormal heat patterns that often indicate
friction, electrical faults, or mechanical overload conditions.
11. What is the primary purpose of lubrication in rolling element
bearings?
A) Increase bearing weight
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A precision alignment procedure for a motor and pump using dial
indicators shows a consistent angular misalignment. Which adjustment
is most appropriate to correct this condition while minimizing shaft
stress during operation?
A) Move both machines laterally in the same direction
B) Adjust only the driven machine vertically without rechecking
C) Adjust the machine feet to correct angular offset at the coupling
face
D) Increase coupling bolt torque to force alignment
Correct Answer: C) Adjust the machine feet to correct angular offset at the
coupling face
Angular misalignment is corrected by adjusting machine positioning at the
feet, particularly using shims and jacking bolts, ensuring the coupling faces
become parallel without inducing stress into the shafts or bearings.
2. During vibration analysis of a rotating shaft, a dominant peak at 1×
running speed is observed. What is the most likely mechanical
condition?
A) Bearing outer race defect
, B) Rotor imbalance
C) Gear tooth wear
D) Electrical rotor bar defect
Correct Answer: B) Rotor imbalance
A strong 1× running speed vibration signature typically indicates mass
imbalance in the rotating assembly, causing centrifugal force variations
once per revolution.
3. Which bearing type is most suitable for handling both high radial and
moderate axial loads in a high-speed application?
A) Plain sleeve bearing
B) Tapered roller bearing
C) Deep groove ball bearing
D) Needle roller bearing
Correct Answer: C) Deep groove ball bearing
Deep groove ball bearings are widely used in high-speed applications due
to their ability to support combined radial and moderate axial loads
efficiently with low friction.
4. What is the primary purpose of using a feeler gauge during machinery
setup?
A) Measure shaft diameter
B) Check lubrication viscosity
C) Measure clearance between mating surfaces
D) Determine bolt torque
Correct Answer: C) Measure clearance between mating surfaces
Feeler gauges are precision tools used to measure small gaps or clearances
between components to ensure proper fit and alignment.
5. In a hydraulic system, what does cavitation most commonly indicate?
A) Excessive fluid viscosity
, B) Air contamination or low inlet pressure
C) Overheating of hydraulic oil
D) High return line pressure
Correct Answer: B) Air contamination or low inlet pressure
Cavitation occurs when vapor bubbles form due to low pressure at the
pump inlet, often caused by air leakage or restricted suction flow.
6. Which rigging configuration provides the greatest mechanical
advantage for lifting heavy loads?
A) Single vertical hitch
B) Basket hitch
C) Double choker hitch
D) Straight vertical lift with chain sling
Correct Answer: B) Basket hitch
A basket hitch doubles the load-bearing points under the load, increasing
lifting capacity and stability compared to other sling configurations.
7. What is the primary function of a flexible coupling in rotating
machinery?
A) Increase torque output
B) Compensate for minor misalignment and absorb vibration
C) Reduce electrical load
D) Increase shaft speed
Correct Answer: B) Compensate for minor misalignment and absorb
vibration
Flexible couplings allow limited misalignment between connected shafts
while reducing transmitted vibration and shock loads.
8. Which condition is most indicative of gear backlash problems in a
gearbox?
A) Smooth operation under load
, B) Excessive noise during steady rotation
C) Tight shaft coupling fit
D) High lubricant level
Correct Answer: B) Excessive noise during steady rotation
Excessive backlash causes irregular gear tooth engagement, resulting in
noise, vibration, and potential wear during operation.
9. What is the most accurate method for checking shaft runout in
precision machinery?
A) Steel ruler measurement
B) Dial indicator mounted on a magnetic base
C) Visual inspection only
D) Torque wrench measurement
Correct Answer: B) Dial indicator mounted on a magnetic base
Dial indicators provide highly precise measurement of shaft deviation
during rotation, making them ideal for runout assessment.
10. In preventive maintenance, what is the main advantage of
thermography inspection?
A) Measures electrical resistance
B) Detects temperature anomalies indicating potential failure
C) Measures shaft alignment
D) Replaces lubrication analysis
Correct Answer: B) Detects temperature anomalies indicating potential
failure
Thermography identifies abnormal heat patterns that often indicate
friction, electrical faults, or mechanical overload conditions.
11. What is the primary purpose of lubrication in rolling element
bearings?
A) Increase bearing weight
