What tool is used for cutting internal threads?

The tool used for cutting internal threads is a tap. Taps are specifically designed to create threads inside a pre-drilled hole, allowing for the insertion of bolts or screws that have corresponding external threads. The design of a tap includes sharp edges that can effectively cut the material as it is turned into the hole, forming a precise thread profile.

In contrast, a chisel is primarily used for carving or shaping material and does not suit the purpose of cutting internal threads. A drill is utilized to create holes but does not have the capability to shape internal threads; its function is solely focused on removing material to make a space. A die is intended for cutting external threads on rods or bolts, making it the opposite of what a tap does. Thus, the tap is the correct answer for creating internal threads, as it directly fulfills that purpose with a specialized design.