ADVANCED THREAD DESIGN
Threads are the most critical element in the drill string. They must resist all stresses of drilling, endure the wear and tear of make-up and break-out, and in the case of dual tube, must do this with a minimum wall thickness to maximize the areas for annular air flow and sample return. Drilling Supply threads incorporate unique design features to achieve superior performance. Torque capacity of a joint largely depends on its shoulder area. Drilling Supply maximizes this area by using an I.D. shoulder in addition to the usual O.D. shoulder.
A stress-relief groove is machined into each pin, above the thread, so that instead of concentrated stresses at the "last engaged thread", the tensile and torsional loads are spread safely over a large area. The controlled "shot blast" on the threads generates beneficial compressive stresses for increased surface hardness, galling resistance and lubricant retention.