... drilling intervals4) API &IADC TCI Tricone Bits 415 Soft Formation TCI Tricone Bits1)The 415 tci bits are ... used to drill low compressive strength, very soft formations.2)TCI bits maximize the use of both conical and ... Available Size: 6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8 ... to minimum.Main Type AvailableSize: 8 1/2",9 1/2",9 5/8",9 7/8",10 5 ... 4 3/4",6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/ ...