... .It is almost suitable for hard rocks, such as limestone, dolomite, chert, firm sandstone, and firm anhydrite and ... .5mm(6 1/8”),158.7mm(6 1/4”),161.9mm(6 3/8”),165.1mm(6 ... 5/8”),349.2(13 3/4”)374.6(14 3/4”)381(15”),393.7(15 1/2 ... 2”),508(20”),558(22”),609.6(24”)660.4(26”) Steel tooth(IADC)111, 121,131117,124 ... /C at sight, western unionProducts show 8 3/4" IADC 527 Kingdream drill bits for rocks HAS series ...