Which hardness test would involve a dial for reading the results?

The Rockwell hardness test involves a dial for reading the results, making it easy to interpret the hardness measurement directly. This method uses an indenter, typically a steel ball or a diamond cone, which penetrates the material under a specified load. The depth of this penetration is then converted into a hardness value, which is displayed on a dial gauge or digital screen.

The dial gauge's readout provides an immediate and straightforward indication of hardness, allowing for quick assessments in various materials. This feature makes the Rockwell test particularly popular in manufacturing and quality control environments, where rapid and reliable results are essential.

In contrast, other hardness tests listed do not primarily use a dial mechanism for reading results. For instance, the Vickers hardness test utilizes a microscope for measuring the diagonal lengths of the indentation left by the indenter. The Shore Scleroscope measures rebound height of a diamond-tipped hammer dropped from a fixed height. The Izod test is primarily used to measure impact resistance and does not provide a hardness measurement in the way that a dial gauge does.