Abstract: A staged tool for boring a hole in a heated element of a material such as metal. The tool is adaptable to being axially forced and operation of the tool causes plastic deformation of the bored material. The tool successively includes, beginning at its front end, a front cylindrical or conical end portion having a first relatively small diameter, a neck followed by a working portion of evolving revolution having a right cross-section which increases in the direction of advancement of the tool, whose major base has a second diameter greater than the first diameter. To improve lubrication during boring, positioned on the neck at the rear of the front end portion is a mass of solid lubricant having a fusion point less than the temperature of the element during the piercing operation. The solid lubricant melts when the tool penetrates into the heated element and the contact surface between the element and the working element is constantly lubricated by a melted lubricating film.