... -600mm-700mm CFG spiral drilling tool is composed of screw drill and the spiral drill pipe, drill the long spiral drilling tool are ... than Phi 800mm general, to import large drilling long spiral drill, spiral drill pipe diameter up to Phi 2500mm, this product ... center pipe: seamless alloy tube without bending, deformation, not. Spiral drill blade : forming a steel cold-drawing, strong toughness, good ...