A clamping mechanism clamps a cutting insert in a tool body. The clamping mechanism has a clamping arm seated within a clamping arm pocket. The clamping arm includes a clamping protrusion extending rearwardly from a rear surface of the clamping arm. The cutting insert has a bore having an insert retaining surface and is seated within an insert pocket. Upon tightening the clamping arm into the tool body, the clamping protrusion presses against the insert retaining surface and the cutting insert is securely abutted within the insert pocket.