What type of tool is commonly used for cutting internal threads?

Taps are specifically designed for cutting internal threads in a hole. The tap features sharp cutting edges that remove material from the inside of a hole to create the helical grooves necessary for threading. This precision allows fasteners, such as screws and bolts, to fit snugly within the threaded hole, ensuring a secure and functional connection in various applications.

Drills, while essential for creating holes, do not form threads; they merely create a cylindrical space. Reamers are used to finish and improve the accuracy of a hole's diameter but do not cut threads either. End mills are versatile tools utilized for a range of milling tasks, such as cutting profiles or slots, not for internal threading. Thus, taps are the appropriate tool for this specific application, as they are engineered to produce internal threads accurately and efficiently.