What is the typical method to diagnose misalignment using a dial indicator or laser alignment tool?

• A. Tighten all fasteners until the shafts stop moving.
• B. Measure runout or misalignment between shafts; ensure near-zero radial misalignment and proper angular misalignment with tolerances.
• C. Ignore alignment and rely on vibration to judge.
• D. Use it to measure electrical resistance in the motor windings.

Answer: (B)

The main idea is to quantify shaft misalignment by measuring how far one shaft sits from the other and how the angle between them changes as you rotate. A dial indicator or laser alignment tool gives a concrete reading of both radial offset (how far the centers are off) and angular misalignment (the tilt between the shafts). The goal is to bring the radial misalignment close to zero and to keep the angular misalignment within the tolerances specified for the equipment.

In practice, you attach the indicator or sensor to one shaft, rotate the machinery, and read the deviation or angle produced by the tool. The readings tell you exactly how much adjustment is needed—shims, moving the machines, or repositioning the coupling—to bring everything into spec.

Why the other approaches aren’t suitable: tightening all fasteners until the shafts stop moving doesn’t measure or correct misalignment and can hide underlying issues. Relying on vibration alone is reactive and may miss the precise amount of misalignment. Measuring electrical resistance in the motor windings doesn’t reveal mechanical shaft alignment problems.