Lightweight drill rod

Claim 1

In an improved lightweight section of drill rod, which is adapted to be coupled with like sections of drill rod in making up a drill string for use with oil well drilling rigs or the like, said section of drill rod being of the type which comprises a length of hollow cylindrical pipe made of aluminum or an aluminum alloy, where said pipe has an internally threaded female end, and a hollow steel tool joint attached to the said end of said pipe, said tool joint having an externally threaded male end which is disposed in mating engagement within the said internally threaded female end of said pipe; the improvement wherein the said externally threaded male tool joint end is provided with an outwardly open blind hole, and the said internally threaded female pipe end is provided with a hole which runs through one sidewall of said pipe, such that when said male tool joint end is matingly engaged in the said associated internally threaded female pipe end, the two said holes are in aligned relationship, and a dowel pin is snugly disposed within the two said holes, and material adjacent the exterior opening of the said hole in the said internally threaded female pipe end is peened over said dowel pin, whereby the said tool joint is permanently and securely attached to said pipe; said internally threaded pipe end being internally relieved at its extreme end portion by an amount corresponding approximately to the height of the threads therein, and the said tool joint having an annular shoulder which mates with the said extreme end portion of said pipe when said pipe and said tool joint are matingly engaged, and said tool joint being torqued down into the said pipe end such that the said extreme end portion of said pipe carries a compressive load; the internal threads in said pipe end and the external threads of said tool joint end being ASA 60° stub threads and a thread locking compound having been applied to said internal and external threads and to said dowel pin; said pipe being an extrusion made of 2014 aluminum alloy in T6 temper, and said tool joint being made of SAE 4150 steel with a Brinell hardness in the range of 293 to 321; said section of drill rod being of the type adapted for use in combination with a carousel type drilling rig and drill rod storage apparatus; and said male tool joint end having a hollow bore which increases in inside diameter toward its said externally threaded male end, and the extreme end portion of said externally threaded male tool joint end being provided with an internal chamfer of about 18°.