What is a single-point tool used for in metalworking?

A single-point tool is primarily used for turning and boring operations in metalworking. During turning, the tool is mounted on a lathe and moves along the length of the material, removing material to achieve the desired shape and dimensions. This process allows for the creation of cylindrical and conical shapes by cutting away excess material as the workpiece rotates.

When it comes to boring, a single-point tool is used to enlarge an existing hole to a precise diameter. This operation is crucial for creating holes that require tight tolerances and specific dimensions.

The other options do not accurately describe the primary functions of a single-point tool. Welding and cutting, for instance, involve different types of tools and processes, while drilling generally employs multi-point tools designed to remove material from the center of a workpiece. Sanding and smoothing are typically done with abrasives and do not fall under the category of operations associated with a single-point tool.