Abstract: A cold-working tool for thrusting an attached mandrel (14) partially through a hole in a metal workpiece and extracting the mandrel from the hole is disclosed. The tool comprises a pneumatic riveting gun (12) that has a body (21), a handle portion (22), and an elongate barret (24). A boss (30) is slidably retained within the outer end of the barrel. The mandrel is attached to the outermost end of the boss. The mandrel has an enlarged diameter portion (38). The riveting gun is connected to a source of pressurized air so that the impulsive forces generated by the riveting gun are transmitted through the boss to the mandrel for thrusting the mandrel through the hole. The tool also includes a housing (56) that substantially encloses the body and barrel of the gun, the housing has a forward end and a rearward end. A nose cap (72) is attached to the forward end of the housing to substantially enclose the boss with the mandrel projecting through a hole in the nose cap.