Which operation is included under the category of holemaking?

Reaming is the correct choice as it falls under the category of holemaking operations. This process is specifically designed to enhance or refine existing holes in a material. It involves using a reamer tool that precisely enlarges the diameter of a hole while improving its finish and ensuring dimensional accuracy. Reaming is essential for achieving a smooth surface and precise fit for components that will be assembled, such as in mechanical assemblies where tolerances are critical.

In contrast, the other options do not primarily focus on creating or modifying holes. Turning involves rotating a workpiece against a cutting tool to create cylindrical shapes; grooving is used to cut narrow channels or grooves into a part; and end milling is a machining process that removes material from a workpiece using a rotating tool, typically to create flat surfaces or complex shapes. While all of these operations are vital in machining, reaming uniquely targets the enlargement and finishing of holes, defining its role in the specific context of holemaking.