Millwright Certification Cheat Sheet 2026

The 30 highest-yield Millwright Certification facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What does a geometric tolerance frame containing a flatness symbol (parallelogram) with a value of 0.02 mean? → The entire surface must lie between two parallel planes 0.02 mm apart
2. What is the primary purpose of a mechanical coupling in a system? → To join two rotating shafts for power transmission
3. What type of coupling is best suited for connecting two shafts with significant angular misalignment? → Gear coupling
4. What is the primary purpose of a V-belt drive in industrial machinery? → To transmit power between shafts using friction between the belt and sheave grooves
5. What is the primary purpose of a keyway and key in a shaft-hub connection? → To transmit torque from the shaft to the hub while preventing relative rotation
6. When press-fitting a bearing onto a shaft, where should the installation force be applied? → Exclusively on the inner ring
7. Which condition would most likely cause a bearing to run hotter than normal during operation? → Over-greasing the bearing housing
8. On a piping drawing, what does a double line with perpendicular short lines across it represent? → A flanged connection
9. What determines the force output of a pneumatic cylinder? → The bore diameter and the applied air pressure
10. Which of the following is a critical component of hazard communication (HazCom)? → Labeling hazardous materials clearly
11. What is the consequence of excessive misalignment between a motor and a pump connected by a flexible coupling? → Premature bearing failure, coupling wear, seal leaks, and increased vibration
12. Before welding two pieces of thick carbon steel plate with a full penetration groove weld, what is the most critical preparation step? → Preheating the material
13. What type of fire extinguisher is appropriate for an electrical fire (Class C)? → CO2 or dry chemical extinguisher rated for Class C fires
14. A sight glass (bull's-eye) on a gearbox housing is used to: → Check and maintain correct oil level
15. When installing a flexible jaw coupling, the correct gap between the two hubs is determined by: → The manufacturer's specification for axial float
16. What is the most likely cause of electrical fluting damage on bearing raceways? → Stray electrical currents passing through the bearing
17. What information does a section view on a mechanical drawing provide that a standard view cannot? → Internal features and material thickness revealed by an imaginary cut
18. Why must sheave grooves be inspected when replacing V-belts? → Worn grooves cause belts to ride too deep, reducing grip and belt life
19. What is the purpose of a tag line when performing a crane lift? → To control the load's rotation and prevent it from spinning or swinging during the lift
20. Why is it important to record bearing clearance measurements before and after installation? → To verify the fit has reduced clearance to the correct operating range
21. Before performing any lift, what is the first thing a rigger must determine? → The weight of the load, including the weight of rigging hardware attached to it
22. What is the term for the condition where the pump and motor shafts are parallel but their centerlines are offset from each other? → Parallel misalignment
23. What does the NEMA rating on an electrical enclosure specify? → The degree of protection the enclosure provides against environmental conditions
24. Which type of bearing is best suited for applications with combined radial and heavy thrust loads? → Tapered roller bearing
25. Why is it critical to remove moisture from a compressed air system? → To prevent corrosion and washout of lubricants
26. Besides lubrication, what is the most critical function of hydraulic fluid in a system? → To transmit power
27. Which protective device monitors all three phases of a motor's supply current and disconnects the motor if a phase is lost or severely unbalanced? → Phase loss and unbalance relay
28. What is the first step in any lockout/tagout (LOTO) procedure? → Informing all affected employees
29. In vibration analysis, what does a dominant 1x frequency (running speed) in the radial direction typically indicate? → Rotor imbalance
30. In Shielded Metal Arc Welding (SMAW), what is the primary function of the flux coating on the electrode? → To provide a shielding gas, deoxidizers, and a slag covering