Tapered drill rod,This provides a hexagonal chuck section to provide leverage for the rotation chuck bushing. It usually has a forged collar to maintain the proper shank striking face position in the rock drill, and a tapered bit end. Tapered steel lengths— available from 0.6m to 3.6 m in length—are measured from the collar to the bit end. Shank Hexagon: 19 x108 mm, 22x 108mm, 25 x108 mm, 25 mmX159 mm 6, 7, 11, 12 degree taper in most lengths, taper degree of drill steel is mostly imports for excellent drilling productivity. For drilling medium-hard to hard and abrasive rock formations,Taper angles of 11 and 12-degrees are normally used on modern drill rigs, like YT28B, YT29A, Y24, YT24, Mobile rock drill pneumatic and hydraulic. Specification 1)Shank Hexagon: 19 x108 mm, 22x 108mm, 25 x108 mm, 25 mmX159 mm 2)Taper Angle: 6, 7, 11, 12 degree 3)Material:high quality alloy steel Application Tapered drill rods are used in granite and marble quarry, gold mine, railway, tunnel, etc.