... Reasonable price4. Better After-Sales ServiceThe Taper Drill Bits Rock are made from grade hard alloy and special steel, generally matched with the ... stone project etc,.We can manufacture the following types according to clients' need taper:4.8,6,7,11,12The diameter for ... taper:15,19,22,24,25(mm) Drill TypeBit diamater (D)TaperWhter hole(d ...