Millwright Certification Precision Measuring and Layout 3

Question 1

What is the purpose of gauge blocks (also known as Jo blocks) in precision measurement?

Accepted Answer

To provide exact known dimensions for calibrating instruments and setting comparative measuring devices

Answer

To replace calipers in the workshop

Answer

To measure surface roughness

Answer

To test material hardness

Question 2

How does a laser alignment system provide more accurate shaft alignment than dial indicator methods?

Accepted Answer

Laser systems eliminate reading errors, bracket sag, and provide real-time graphical adjustment guidance

Answer

Lasers are louder and easier to detect

Answer

Laser systems cost less than dial indicators

Answer

Laser alignment only works on small machines

Question 3

What is the correct procedure for zeroing a dial indicator before taking measurements?

Accepted Answer

Place the indicator on a known reference surface, ensure the contact is preloaded at least half a revolution, then rotate the bezel to zero

Answer

Tap the indicator face until it reads zero

Answer

Set the indicator to zero while it is off the workpiece

Answer

Hold the indicator upside down and adjust the needle

Question 4

What is the advantage of using an inside micrometer over a telescoping gauge for measuring bore diameters?

Accepted Answer

Inside micrometers provide a direct reading without needing a transfer measurement, reducing the chance of error

Answer

Inside micrometers are cheaper

Answer

Inside micrometers can measure external dimensions too

Answer

Telescoping gauges are obsolete

Question 5

When performing layout work, why is a scriber preferred over a pencil for marking metal surfaces?

Accepted Answer

A scriber produces a fine, permanent, precise line that does not rub off during machining or fitting operations

Answer

Scribers are available in more colors

Answer

Pencils are not strong enough to mark metal

Answer

Scribers are safer to use

Question 6

What is a sine bar used for in precision measurement?

Accepted Answer

Setting up or measuring precise angles using gauge blocks and the trigonometric sine function

Answer

Measuring the length of bars and rods

Answer

Checking bar stock for straightness

Answer

Measuring the frequency of vibrations