... Taper(°) Drill diameter Taper(°) mm in mm in 28 1 3/32 6,7 45 1 3/4 6,7,11,12 30 ... 3 1/2 6,7,11,12 36 1 13/32 6,7,11,12 102 4 6,7,11,12 38 1 ... 1/2 6,7,11,12 115 4 ... 1 21/32 6,7,11,12 152 6 6,7,11,12 43 1 11/16 6,7,11,12 PS: We ... bit is strong radial abrasion resistance and it is applicable to drill fracture rock and abrasive layers. It is suitable for kinds ...