What does a dial indicator primarily measure in maintenance work?

What does a dial indicator primarily measure in maintenance work?

• A. Electrical current
• B. Surface roughness
• C. Small linear displacements, runout, or alignment; read in thousandths of an inch or hundredths of a millimeter
• D. Fluid level

Answer: (C)

A dial indicator is all about tiny linear movements and how true a feature is to a reference surface. It converts small motions of its contact plunger into a magnified dial reading, so you can quantify very small displacements. In maintenance, this lets you check runout on a rotating part, verify alignment between surfaces, or assess straightness and parallelism, with readings typically in thousandths of an inch or hundredths of a millimeter. For example, you can mount the indicator and rotate a shaft to see how far the shaft departs from true rotation, or drag the probe across a surface to detect variation in flatness. It isn’t used for electrical current, surface roughness measurements, or fluid level, which require different tools.

A dial indicator is all about tiny linear movements and how true a feature is to a reference surface. It converts small motions of its contact plunger into a magnified dial reading, so you can quantify very small displacements. In maintenance, this lets you check runout on a rotating part, verify alignment between surfaces, or assess straightness and parallelism, with readings typically in thousandths of an inch or hundredths of a millimeter. For example, you can mount the indicator and rotate a shaft to see how far the shaft departs from true rotation, or drag the probe across a surface to detect variation in flatness. It isn’t used for electrical current, surface roughness measurements, or fluid level, which require different tools.