FREE Millwright Precision Measuring and Layout Questions and Answers

Question 1

A standard outside micrometer shows the sleeve marking at 7.5 mm, the thimble is aligned with the 28th graduation (0.28 mm), and the vernier scale's 3rd line aligns (0.003 mm). What is the final measurement?

Accepted Answer

7.783 mm

Answer

The final measurement is the sum of the readings from the sleeve, thimble, and vernier scale. In this case, it is 7.5 mm (sleeve) + 0.28 mm (thimble) + 0.003 mm (vernier), which totals 7.783 mm.

Question 2

When checking for shaft runout using a dial indicator, the Total Indicated Reading (TIR) is 0.004 inches. What does this value represent?

Accepted Answer

The total diametrical variation in concentricity

Answer

Total Indicated Reading (TIR) represents the full range of movement of the indicator's needle during one complete rotation of the shaft. This value is twice the amount of the shaft's centerline offset, indicating the total variation from a perfect circle.

Question 3

What is the primary purpose of applying layout dye (bluing) to a workpiece before scribing?

Accepted Answer

To create a high-contrast background for scribed lines

Answer

Layout dye provides a thin, dark, and uniform background on the metal's surface. This creates a high contrast that makes the fine, bright lines made by a scriber or divider much easier to see.

Question 4

When using a feeler gauge to check the clearance between two machine parts, what is the correct technique?

Accepted Answer

The correct blade should have a slight, even drag

Answer

The correct technique is to select a blade that slides into the gap with a slight, even drag. If the blade is too loose, the measurement is inaccurate, and if it must be forced, it can damage the blade or the machine parts.

Question 5

On a vernier caliper, the zero on the vernier scale is just past the 24 mm mark on the main scale. The 16th line on the vernier scale aligns perfectly with a line on the main scale. If the caliper's resolution is 0.02 mm, what is the measurement?

Accepted Answer

24.32 mm

Answer

First, take the main scale reading, which is the last full millimeter before the vernier's zero (24.00 mm). Then, find the aligning line on the vernier scale (16) and multiply it by the instrument's resolution (16 * 0.02 mm = 0.32 mm). Add the two values together: 24.00 mm + 0.32 mm = 24.32 mm.

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FREE Millwright Precision Measuring and Layout Questions and Answers