Millwright Certification Precision Shaft Alignment Techniques 2

Question 1

What is soft foot, and why must it be corrected before performing shaft alignment?

Accepted Answer

It occurs when one or more machine feet do not sit flat on the base, causing the frame to distort when bolts are tightened

Answer

It is a type of foundation crack

Answer

It is wear on the shaft coupling

Answer

It is a vibration frequency

Question 2

In reverse dial indicator alignment, what does each indicator measure?

Accepted Answer

Each indicator measures the radial position of the opposite shaft, giving both offset and angularity data

Answer

Shaft speed and torque

Answer

Shaft diameter and bearing clearance

Answer

Temperature and vibration levels

Question 3

What is thermal growth, and how is it accounted for during cold alignment?

Accepted Answer

Predictable increase in machine height as components reach operating temperature, compensated by offsetting cold alignment targets

Answer

Expansion of the coupling during operation

Answer

Growth of the foundation concrete

Answer

Expansion of alignment shims

Question 4

Why is it important to use proper shim practices during alignment?

Accepted Answer

Incorrect shimming introduces errors: corroded shims, too many shims, or wrong thickness shims prevent accurate and stable alignment

Answer

Shims are decorative

Answer

Shims reduce vibration automatically

Answer

Shims are only used for appearance

Question 5

What alignment readings at the 12, 3, 6, and 9 o'clock positions indicate pure parallel (offset) misalignment with no angularity?

Accepted Answer

The 12 and 6 readings are equal and opposite, and the 3 and 9 readings are equal and opposite

Answer

All readings are zero

Answer

The 12 reading is maximum and all others are zero

Answer

All four readings are identical

Question 6

What is the primary benefit of performing precision alignment on rotating machinery?

Accepted Answer

It dramatically extends bearing, seal, and coupling life while reducing vibration and energy consumption

Answer

It makes the machine look better

Answer

It increases the machine's rated speed

Answer

It eliminates the need for lubrication