What are threads in machining primarily used for?

Threads in machining are primarily used to create fasteners. Fasteners such as nuts and bolts rely on threads to provide mechanical fastening capabilities. The helical design of threads allows for a strong grip between two parts, enabling them to be securely joined. This mechanical interlocking is crucial in a wide range of applications, from structural assemblies to machinery.

While there are other factors in machining processes, such as cutting speed, surface finish, and support for workpieces, these do not pertain specifically to the function of threads. Cutting speed relates to the efficiency of the machining process, surface finish pertains to the quality of the machined surface, and support of the workpiece deals with stability during machining operations. In contrast, threads are distinctly recognized for their role in fastening and joining components, making option B the correct answer.