What tool is used for cutting internal screw threads?

The correct tool for cutting internal screw threads is the tap. Taps are specifically designed for creating internal threads in a pre-drilled hole by removing material as they are rotated. They come in various sizes and thread types to accommodate different applications and standards.

Using a tap ensures that the threads created inside a component are precise and suitable for fastening screws or bolts, achieving the desired fit and strength. Taps are commonly employed in metalworking, woodworking, and plastic fabrication, making them a vital tool in various industries.

In contrast, other tools mentioned serve different purposes; for example, dies are used for cutting external threads on rods or shafts, while chasers are typically utilized for shaping and finishing threads or profiles. Reamers are designed to enlarge pre-existing holes to a precise diameter and improve their surface finish, rather than creating threads. Understanding the specific applications of each tool is essential for effective and accurate machining.