Abstract: An earth boring system is provided with universal cutter means for boring in all types of formations. The cutter means is mounted on a drill bit body or cutterhead with said bit or cutterhead functioning to form a hole in the earth formations. At least two annular rows of major inserts are mounted in the cutter means. The major inserts project from the surface of the cutter means a substantial distance for forming circular kerfs in the earth formations being bored. An annular row of minor inserts are mounted in the cutter means between the two annular rows of major inserts. The minor inserts project from the surface of the cutter means a distance that is substantially less than the distance the major inserts project from the surface of the cutter means.

Abstract: A drill bit is shown for enlarging a pilot hole into a larger diameter hole by disintegrating the earth formations that surround the pilot hole. The bit includes a cutterhead with a multiplicity of saddles containing rolling cutters for contacting and disintegrating the formations that surround the pilot hole. The rolling cutters are mounted so that the cutter face profile of the cutters extends in a uniform manner to the edge of the pilot hole and eliminates uncut bottom. A drive stem or stinger projects from the cutterhead. The lower portion of the drive stem or stinger comprises extensions that reach over or "bridge" the inner legs of the center saddles and extend into the available vacant areas between the saddles for attachment to the body of the cutterhead.