Which type of caliper is mainly used for locating the center of a shaft?

The hermaphrodite caliper is specifically designed for locating the center of a shaft due to its unique design, which features one leg that is pointed and another leg that is flat. This shape allows for accurate marking of diameters and establishing a center point, which is crucial when working with rotational components such as shafts. The pointed leg can easily be placed on the edge of the shaft while the flat leg can be used as a guide to draw lines across the shaft, thereby helping to identify the center line accurately.

In contrast, while digital calipers and vernier calipers provide precise measurements, they are not specifically tailored for finding the center of shafts; their primary purpose is measuring dimensions. Machinist calipers, although useful, do not have the specific design feature that facilitates locating shaft centers as effectively as hermaphrodite calipers do. Therefore, the choice of the hermaphrodite caliper is warranted in this scenario for tasks centered on locating the center of a shaft.