A dial indicator is used to detect what condition in a shaft coupling?

• A. No movement
• B. Any movement
• C. Rotation
• D. Temperature change

Answer: (B)

Dial indicators are precision devices that convert tiny linear motions into a readable dial movement. In a shaft coupling, you use it to monitor how the surface being measured moves relative to a fixed reference. Because it measures displacement, any deviation from the reference position shows up as a deflection on the dial. That means it can reveal looseness, misalignment, runout, or end play—the kinds of movement that indicate the coupling isn’t behaving quite right. It isn’t a tool for measuring rotation speed or temperature, so those conditions wouldn’t be detected by a dial indicator. So the condition being detected is any movement of the shaft surface relative to the setup.