Free NCCER Industrial Maintenance Mechanic Knowledge Assessment Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NCCER Industrial Maintenance Mechanic Knowledge Assessment practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1During maintenance on a machine with a lockable energy isolating device, which energy control method is normally required?

   1. A. Attach a warning tag alone
   2. B. Apply lockout to the isolating device
   3. C. Use the normal stop button alone
   4. D. Post a warning beside the machine

   Answer: B

   Explanation: "If an energy isolating device is capable of being locked out, the employer's energy control program under paragraph (c)(1) of this section shall utilize lockout, unless the employer can demonstrate that the utilization of a tagout system will provide full employee protection as set forth in paragraph (c)(3) of this section." Because the device can accept a lock, lockout is the normal method. A tag-only approach requires the specified demonstration of full protection; a stop button or nearby notice does not isolate energy.

   Reference: OSHA 29 CFR 1910.147 — The control of hazardous energy — 1910.147(c)(2)(ii)

2. 2Before using a sling for an industrial lift, when must its fastenings and attachments be inspected for defects?

   1. A. Only after an overload event
   2. B. Each day before use
   3. C. Once every three months
   4. D. Only at annual certification

   Answer: B

   Explanation: "Each day before being used, the sling and all fastenings and attachments shall be inspected for damage or defects by a competent person designated by the employer." The daily pre-use inspection includes fastenings and attachments; an annual interval alone does not meet that condition.

   Reference: OSHA 29 CFR 1910.184 — Slings — 1910.184(d)

3. 3A rectangular machine base measures 8 ft by 5 ft. What is its plan area?

   1. A. 13 ft²
   2. B. 26 ft²
   3. C. 40 ft²
   4. D. 80 ft²

   Answer: C

   Explanation: "A = h * b" Multiplying the two perpendicular dimensions gives 8 × 5 = 40 square feet; the other values reflect addition, perimeter, or doubling.

   Reference: NASA Glenn Research Center — Area — Area, rectangle formula

4. 4A mechanic must confirm that a replacement-part drawing is the intended sheet. Which title-block entry is normally the unique filing identifier?

   1. A. Drawing number
   2. B. Drawing scale
   3. C. Approval date
   4. D. Vendor address

   Answer: A

   Explanation: "Drawings are usually filed by their drawing number because the drawing title may be common to several prints or series of prints." The drawing number uniquely identifies and files the sheet; titles can repeat across a series.

   Reference: DOE Fundamentals Handbook: Engineering Symbology, Prints, and Drawings, Volume 1 — Module 1, The Title Block, p. 2

5. 5A valve's removable cover is damaged at its joint to the body. Which component forms this second principal pressure boundary?

   1. A. Valve bonnet
   2. B. Valve yoke
   3. C. Valve handwheel
   4. D. Valve indicator

   Answer: A

   Explanation: "The bonnet is the second principal pressure boundary of a valve." The bonnet closes the body opening and its joint retains pressure; a yoke, wheel, or indicator does not serve that boundary.

   Reference: DOE Fundamentals Handbook: Mechanical Science, Volume 2, Module 4 Valves — Module 4, Valve Bonnet, p. 3

6. 6Before installing a replacement rolling bearing, which check confirms that the supplied bearing matches the assembly?

   1. A. Compare its package designation with the drawing and parts list
   2. B. Match only the bore size to the removed bearing
   3. C. Match only the outside diameter to the housing
   4. D. Match only the seal style to the old bearing

   Answer: A

   Explanation: "the bearing number stamped on the package agrees with the designation given on the drawing and in the parts list" The designation check controls the specified replacement; appearance does not establish the bearing identity.

   Reference: Schaeffler: Mounting and Dismounting of Rolling Bearings — Section 2.2, The Right Bearing, p. 8

7. 7What mechanism adds energy to the fluid in a centrifugal pump?

   1. A. A piston traps a fixed volume each stroke
   2. B. A spinning impeller adds kinetic energy
   3. C. A screw displaces sealed fluid chambers
   4. D. Sliding vanes trap fluid as the rotor turns

   Answer: B

   Explanation: "Centrifugal pumps work by adding kinetic energy to a fluid using a spinning impeller." This distinguishes the centrifugal mechanism from positive displacement.

   Reference: Improving Pumping System Performance: A Sourcebook for Industry — Section 1, Pumping System Components, p. 4

8. 8A mechanic measures unequal gaps between coupling faces at successive 90-degree positions. What alignment fault does this indicate?

   1. A. Angular misalignment
   2. B. Parallel offset only
   3. C. Normal axial float
   4. D. Bearing end play only

   Answer: A

   Explanation: "if they do not match, it indicates angular misalignment." Unequal face gaps reflect an angle between shaft axes.

   Reference: Prüftechnik: What Is Pump Alignment? A Complete Guide — How to Check Pump Coupling Alignment with Feeler Gauges

9. 9In a firetube boiler, what flows inside the boiler tubes?

   1. A. Combustion gases
   2. B. Boiler feedwater
   3. C. Only condensed steam returning from users
   4. D. Only water-treatment chemicals

   Answer: A

   Explanation: "In firetube boilers, the combustion gases pass inside boiler tubes" The hot gases run through the tubes while boiler water surrounds them.

   Reference: DOE: Improving Steam System Performance, Second Edition — Section 1, Generation, Firetube boilers, p. 4

10. 10A mechanic has switched off a conveyor at its control panel. Which device can physically isolate its electrical energy for lockout?

    1. A. Start push button
    2. B. Speed selector switch
    3. C. Manually operated circuit breaker
    4. D. Run/stop selector switch

    Answer: C

    Explanation: "Energy isolating device. A mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; a disconnect switch; a manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors, and, in addition, no pole can be operated independently; a line valve; a block; and any similar device used to block or isolate energy. Push buttons, selector switches and other control circuit type devices are not energy isolating devices." The breaker physically isolates energy. The other choices are control-circuit devices and do not serve as energy isolating devices.

    Reference: OSHA 29 CFR 1910.147 — The control of hazardous energy — 1910.147(b), Energy isolating device