A boring tool for use with compacted graphite iron materials includes at least one self-propelled rotating cutter insert. The insert is carried in a cartridge in which the insert is rotatable about is axis which is a secondary axis relative to a boring tool body in which the cartridge is mountable and which is rotatable about a primary axis. In the tool, the insert has its cutting point most distant from the tool axis that is the location at which axial and radial rake angles are defined to assure that the insert rotates during boring about its axis in the correct direction and at sufficient speed to assure cooling of the insert.
