What is the purpose of a reamer in machining?

A reamer is specifically designed to finish the surface of an already drilled hole, which is why it serves this important function in machining processes. It enhances the dimensional accuracy and surface finish of a hole by removing a small amount of material, thereby achieving tighter tolerances than what is typically possible with a standard drill bit.

Reamers are particularly effective in refining the size and smoothness of a hole, ensuring that it meets specific engineering requirements for fit or function, such as allowing a shaft to pass through with minimal clearance. This process is crucial in applications where precision is key, such as in the assembly of mechanical components.

In contrast, creating threads in a hole is the role of tapping tools, while measuring hole diameters is usually done with calipers or gauges rather than using a reamer. Additionally, cutting raw material to a desired size typically involves tools like saws or mills, not reamers, which are specialized for finishing rather than initial cutting or shaping.