Abstract: A method of applying a protective shield to a drill pipe tool joint including positioning a centering hub on the end of the tool joint, positioning a bifurcated mold around the tool joint, the mold having a rearward end engaging the drill pipe and a forward end engaging the hub thereby centering the mold on the tool joint, the internal diameter of the mold being greater than the external diameter of the tool joint providing an annular cavity defining the preselected shape of the protective shield, injecting liquid plastic material through an opening in the mold to fill the annular cavity, allowing the material to solidify, and removing the mold hub.

Abstract: In a rotary drilling system for drilling deep, large-diameter bore holes in the earth, using multiple lengths of drill pipe joined together by threaded tool joints, the improvement in means to prevent relative rotation while joining and unjoining the two parts of the threaded-together tool joints, after the tool joints has been made to a desired torque, comprises a retaining cylinder or ring, of somewhat larger diameter than the diameter of the tool joints, positioned to surround a tool joint with an annular space of a selected radial dimension. There is at least one pair of longitudinally slidable cams or wedges that slide within longitudinal grooves on the inside surface of the retainer ring. Hydraulic means are provided to move the pair of wedges longitudinally toward each other, along the sloping grooves until they are wedged between the retaining ring and the outer surface of the tool joint, one wedge opposite each part of the tool joint.