Abstract: A tool unit for performing a chamfering operation on a workpiece is disclosed. The tool unit includes a body, a plunger, at least one insert holder, and at least one cutter insert. The body includes a bore, and the plunger is movably positioned within the bore. The insert holder is coupled to the body and is in engagement with the plunger. The cutter insert is coupled to the at least one insert holder. The cutter insert includes a cutting edge adapted to be positioned at a cutting angle relative to the workpiece, and the cutting angle is varied relative to the workpiece upon a movement of the plunger within the bore.