REAMER

A reamer is a cylindrical or conical cutting tool used to enlarge the diameter of a hole with high precision. It is similar to a drill bit but is designed either for manual use (with a handle) or mounted on a machine (such as a drill press, lathe, or milling machine). Unlike a drill bit, which cuts only at its tip, the reamer cuts along its sides, allowing it to achieve very precise hole diameters.