One end connect with the shank end, the other end connect with bit end. Transmit the impacting power and torque from shank to bit, the lifespan depends on the material, thread processing. ï?¬ Made from the same steel as Sandvik; 23CrNi3Mo, which is in same league as Sandvik Sandbar 64, is applied as drill rod material. ï?¬ Friction welding workmanship . It makes the thread and the body integrated without broken. ï?¬ Advanced production process: produced by CNC machining and advanced heat treatment. It will connect the drill rod and the drill bit more better. â?¢ Optimize processing procedure, entirely automatic threading equipment to finish the thread naturally and reduce the concentration of stress. ï?¬ Full-carburization drill rod for high wear-resistance and strength. Carburizing process is applied to promote surface hardness, thus grant better wearing quality and lifespan for the drill rods; ï?¬ Quality close to world famous brands, but our prices are much more competitive. ï?¬ Complete types of drill rod for various drilling scenarios. Advanced engineering, precision manufacturing and high-grade materials assures the reliable quality of our drill rod. When you send inquiry, please tell the information as following: Diameter + length +thread