When dial indicator readings are taken on the rim of the coupling by rotating through 180 degrees, what type of misalignment does this indicate?

When dial indicator readings are taken on the rim of the coupling by rotating through 180 degrees, the method primarily indicates parallel misalignment. Parallel misalignment occurs when the shafts are offset from each other laterally, meaning they are not aligned vertically or horizontally even though they may still be facing the same direction.

In this scenario, as the dial indicator is moved around the circumference of the coupling and readings are taken, the variations in the dial indicator will point to a consistent offset rather than any angular displacement, which would be indicated by variations that change with a different rotational position. Thus, uniform readings across a 180-degree rotation suggest that the shafts are aligned but not parallel, confirming that the misalignment observed is due to the offset of the shafts rather than any angular misalignment.