A heavy coupling element for drill pipe having coarse, tapered threads and sealing shoulders designed to sustain the weight of the drill stem, withstand the strain of repeated make-up and break-out, resist fatigue, resist additional make-up during drilling, and provide a leak-proof seal. The male section (pin) is attached to one end of a length of drill pipe and the female section (box) is attached to the other end. Tool joints may be welded to the drill pipe, screwed onto the pipe, or a combination of screwed on and welded.
Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global Standards
Forged or rolled steel component for drill-pipe designed to be welded to the drill-pipe body and having a rotary shouldered connection.
Source: API SPEC 5DP, Specification for Drill Pipe, First Edition, August 2009. Global Standards
Heavy coupling element for drill pipe having coarse, tapered threads and sealing shoulders.
Source: API SPEC 7-1, Specification for Rotary Drill Stem Elements, First Edition, March 2006 (Addendum April 2011). Global Standards