A clamping tool holder (10) includes a tool holder body (12) and a clamp (10) for clamping a cutting insert (22). The clamp (40) causes the cutting insert (22) to press against the bottom and the side walls of an insert-receiving pocket (14) of the tool holder body (12). The tool holder body (12) has an inclined surface (34) sloping inward in a direction away from the insert-receiving pocket (14) . The clamp (40) has an inclined surface (50) that acts as a ramp with the inclined surface (34) of the tool holder body (12). A guide pin (60) prevents the clamp (40) from twisting during tightening or loosening of the clamp. When a clamp screw (52) is tightened, a nub (48) of the clamp (40) engages only an inside rearward surface of a mounting bore (24) of the insert and the top surface (22a) of the cutting insert (22). In addition, only a forward lower face (46a) of a head portion of the clamp screw (52) engages a top surface (22a) of the clamp (40).
