Box-and-pin joint (tool joint) ‚ÄĒ a coupling element of drilling pipes for making-up a column (string). Box-and-pin joint consists of nipple (pin) and coupling (box) fixed at the end of drilling pipe. The joint is connected with the pipe via conical thread or by welding ‚Äď in the last case the joint elements are usually called connecting ends ‚Äď a nipple end and a spigot end. Screwed tool joints are usually assembled with the pipes via hot/hot procedure (the elements of the joint are heated up to 400‚Äď450 ¬į–°). Drilling pipes are screwed together via pipe joint consisting of coarse pitch conical thread and shoulder bearing faces (coupling face and nipple shoulder) assuring air tightness and quick assembly-disassembly. To decrease alternate stresses in the threaded joint stabilizing bands on the pipe and bores on the joint are used.