This 4-blade step drill has been developed with a proprietary 4-blade shape that greatly improves the life and sharpness of the blade. In order to spread the holes from small to large diameters, there is less recoil (shock) or vibrations when drilling, allowing for stable drilling work. The shank is a hex shaft, so it does not slip even when attached to a drill chuck, and can be used with impact drivers. The tip is thinned for easy sticking to the material and does not require punch work with the center punch.