... and so on. These kinds of bits are suitable for different complex formation, shales, limestone, cobblestone, dolomite, chert, etc. Regular Bit ... ", 36", 38", etc, and any diameters can be customized, maximum diameter is 1600mm. Model114, 117, 127, 437, 517, 617, 637 ... Hole openers, do not hesitate to contact me,thanks.Sunny different diameter of Hole opener/ Bit cones/ Assembly Drill Bit/ TCI tricone ...