AIT Measurement Tools 5 — Questions and Answers
Question 1: A level vial bubble should be centered for a level reading. If the bubble is off to the left, the left side of the tool is:
- Lower than the right side
- Higher than the right side (Correct answer)
- Level with the right side
- Cannot be determined
Correct answer: Higher than the right side
The bubble moves toward the high end, so a bubble shifted left means the left side is elevated.
Question 2: What is the purpose of the lock nut (thimble lock) on a micrometer?
- To prevent the frame from bending
- To lock the spindle in position after a measurement so the reading is preserved (Correct answer)
- To adjust the zero calibration
- To tighten the anvil
Correct answer: To lock the spindle in position after a measurement so the reading is preserved
The lock nut clamps the spindle so the micrometer can be removed from the work without losing the reading.
Question 3: A carpenter's folding rule differs from a steel tape primarily because it:
- Is more accurate
- Has rigid sections that maintain shape, useful for inside measurements without bending (Correct answer)
- Can measure longer distances
- Is waterproof
Correct answer: Has rigid sections that maintain shape, useful for inside measurements without bending
The rigid folding sections hold their shape, making inside measurements easy without the tape sagging or curling.
Question 4: When a laser level is used in construction, what does it project to establish a reference?
- A plumb bob line only
- A visible beam or plane of light at a consistent elevation or angle (Correct answer)
- A digital readout of height
- An infrared beam only detectable with a receiver
Correct answer: A visible beam or plane of light at a consistent elevation or angle
A laser level projects a visible (or detector-readable) plane or line of light that defines a consistent level or angled reference.
Question 5: When checking the flatness of a machined surface with a straightedge and feeler gauges, what does the feeler gauge measure?
- The angle of the surface
- The gap between the straightedge and the surface (deviation from flat) (Correct answer)
- The hardness of the surface
- The surface roughness
Correct answer: The gap between the straightedge and the surface (deviation from flat)
The feeler gauge measures the gap between the known-flat straightedge and the surface, revealing high and low spots.
Question 6: An apprentice measures a shaft with a micrometer and gets 1.2505 inches, but the blueprint calls for 1.250" ± 0.001". Is the part in tolerance?
- No, it exceeds the upper limit of 1.251"
- Yes, 1.2505" is within the 1.249" to 1.251" range (Correct answer)
- No, it is below the lower limit
- Cannot determine without the actual micrometer reading
Correct answer: Yes, 1.2505" is within the 1.249" to 1.251" range
The tolerance range is 1.249" to 1.251", and 1.2505" falls within that range, so the part is acceptable.
Question 7: What is the main reason measuring tools should be kept away from heat sources and stored at room temperature?
- To prevent rust
- Because thermal expansion and contraction change the dimensions of precision instruments and workpieces (Correct answer)
- To preserve lubricants
- To prevent electrical damage
Correct answer: Because thermal expansion and contraction change the dimensions of precision instruments and workpieces
Metals expand when heated and contract when cooled; temperature changes alter the dimensions of tools and workpieces, causing measurement errors.
AIT Measurement Tools 5
A level vial bubble should be centered for a level reading.
If the bubble is off to the left, the left side of the tool is: