Spiral drill pipe even extension drill rod. Extension drill rod can be divided into the internal and external layer; outer circle has six key. To form a three track rail. Coinciding with the special power head bond with the transmission torque; drill pipe inner tube is depressed note concrete used. But also strengthen the drill pipe; the extension drill rod of special structure. The CFG long helical drilling in is not increased, without increasing the size of a rig the conditions to increase drilling depth. And thus the whole device with a low center of gravity, greatly improves the stability of the whole machine.