Intro to Millwright Practice Exam 2025 - Free Millwright Skills Practice Questions and Study Guide

The tool that specifically widens or shapes a hole drilled in metal is the reamer. Reamers are designed to enhance the surface finish and precise dimensions of an existing hole, allowing for a tighter tolerance than what a drill can achieve. They work by removing small amounts of material around the wall of the hole, creating a smoother and more accurate fit for components such as bearings or dowel pins.

While drills are primarily used to create holes in metal, they do not provide the level of precision that reamers do. Boring tools are also associated with enlarging holes but are typically used in a different context, often in conjunction with a machine to remove more significant amounts of material and may be more suited for operations within a machining setup rather than handheld or light-duty work. End mills cut slots and shapes in a piece, but they are not designed specifically for enlarging pre-drilled holes. Thus, reamers stand out as the optimum choice for the task at hand.