This is the speciality pipe used by drilling rigs for the actual drilling of the well. It is very strong and made to withstand a great deal of stress and rough treatment. This is the largest “expendable” item used by drilling contractors. Drill pipe wears out over a period of time and is replaced regularly. Drill pipe uses unique and very high strength connectors called “tool joints.” A tool joint is integral or part of a joint of drill pipe. These connections are manufactured separately from the drill pipe body or tube, then joined to the tube by conventional welding or by friction welding. Drill pipe is more expensive to manufacture than tubing or casing due to the special steel properties required and the addition of a tool joint to each end of the tube. GrantPrideco is a major manufacturer of drill pipe.