Abstract Establishes the nomenclature and lays down the leading dimensions to ensure interchangeability within the limits of system B of the following equipment: drill rods and couplings, fishing rods and couplings; casing tubes, casing drive shoes, casing shoe bits, casing bits and sediment tubes; core barrels, core bits, core lifters and reaming shells. Specifies the characteristics of a range of equipment for drilling holes having diameters from 36 mm to 146 mm and yielding cores from 22 mm to 120 mm in diameter.