Second grade reducing percussion bit

The utility model relates to a can improve effectively to strike and bore drilling efficiency, can reach required drilling diameter's second grade reducing percussion bit again fast, including percussion bit, the diameter of percussion bit drilling rod begins grow gradually by the initiating terminal, and the spiral chip groove cutting part that distributes on the reducing drilling rod has inlayed hole enlargement alloy head. The advantage: both having improved effectively to assault and having bored drilling efficiency, fast superdata realizes the diameter of required drilling again to save labour, laborsaving. 本实用新型涉及种既能有效地提高冲击钻钻孔效率，又能快速达到所需钻孔直径的二级变径冲击钻头，包括冲击钻头，所述冲击钻头钻杆的直径由起始端开始逐渐变大，分布在变径钻杆上的螺旋排屑槽刃部嵌有扩径合金头。优点：既有效地提高冲击钻钻孔效率，又快速达实现所需钻孔的直径，并且省工、省力。