... ),9 5/8"(245mm), 11 5/8"(295mm),12 1/4"(311mm), 13 5/8"(346mm),14 3/4"( ... 374mm), 15 1/2"(394mm)16"(406mm), 17 1/2"(445mm),18"(457mm), 26"(660mm)Model ... 346,347RPM(r/min)140~60WOB(KN/mm)0.35~1.0Thread Connection7 5/8 reg pinBearing typeSealed bearing and ... different tooth shape, tooth density and tooth exposure height. 17 1/2" milled tooth tricone bits for well drilling mine drilling ...