... , 7 Degree 3.Water Hole: 2 4.Body: Normal Rock Bits The Advantages Of Taper Drill Rock Bits1. Higher Quality2. With ... . More Reasonable price4. Better After-Sales ServiceThe Taper Drill Rock Bits are made from grade hard alloy and special steel, generally ... clients' need taper:4.8,6,7,11,12The diameter for taper:15,19,22,24,25(mm) Drill TypeBit diamater ...