... /8"(346mm),14 3/4"(374mm), 15 1/2"(394mm)16"(406mm), 17 1/2"(445mm),18"(457mm), 26"(660mm)Model NO. ... limestone, etcCirculation systemMud pumpMaterialAlloy steel, carbideDelivery termsBy sea or by airapplicationPetroleum and gas, water well, mining and tectonic industries, ... the conventional drilling. It is suitable for various formations by matching cutting structure with different tooth shape, tooth ...