What tool would you use to measure alignment of shafts in a pump?

To measure the alignment of shafts in a pump, the dial indicator is the preferred tool. A dial indicator provides precise measurements of the shaft's position and can detect any misalignments with great accuracy. Its design allows the operator to see small deviations as the shafts are rotated, making it an ideal instrument for evaluating alignment, which is crucial for preventing operational issues and ensuring the efficient functioning of the pump.

Using a dial indicator is critical in alignment tasks because it measures linear displacement and can indicate how much one shaft is misaligned relative to another. This information can be invaluable in making necessary adjustments to correct the alignment, thus extending the life of the pump and reducing wear on components.

In contrast, other tools listed serve different purposes. A tachometer measures rotational speed, a pressure gauge measures pressure within a system, and a flow meter quantifies the volume of fluid passing through a system. Although these instruments are important within their contexts, they do not provide the specific data needed to assess shaft alignment directly. Therefore, the dial indicator stands out as the most appropriate choice for this task.