... 5''×36'' Hole opener/ Bit cones/ Assembly Drill Bit/ TCI tricone bit/ Milled tooth bit for drilling hole 1. Bit cones (segment) are spited ... complex formation, shales, limestone, cobblestone, dolomite, chert, etc. Regular Bit Diameters: 28 ", 32", 36", 38", etc, and any ... ,thanks.Sunny different diameter of Hole opener/ Bit cones/ Assembly Drill Bit/ TCI tricone bit/ Milled tooth bit for drilling hole