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 1.42 in to 5.74 in and yielding cores from 0.87 in to 4.72 in in diameter.