The University of Drilling is a practical learning site, not an accredited school.

Drill Pipe

The parts of a joint of drill pipe.
Cross section of the pin and box of a tool joing.

Drill pipe comprises seamless steel or aluminium pipe made up in the drill stem between the kelly or top drive on the surface and the drill collars on the bottom hole assembly.


Drill pipe is usually rotated while drilling fluid is circulated through it. Joints of pipe are about 30 feet long and coupled together with tool joints welded to the pipe body.


The drill pipe body is the tubular part of the drill pipe between the tool joints, which are on each end of the pipe.


A tool joint is a heavy coupling element welded to drill pipe which is made of special alloy steel. Tool joints have coarse, tapered threads and seating shoulders designed to sustain the weight of the drill stem, withstand the strain of frequent coupling and uncoupling, and provide a leak-proof seal.


The male section of the joint, or the pin, is attached to one end of a length of drill pipe, and the female section, or the box, is attached to the other end.