The drilling bit capable of cutting in both axial direction and side direction is one slender cylinder, which includes one front drilling end for axial cutting, one side cutting section extending from the drilling end, and bit handle behind the side cutting section. The side cutting section includes a pair of opposite spiral grooves at the angle of 13-17 deg and with sharpened edge around the drilling center. The drilling center has diameter proportional directly to the bit diameter and cutting edge length is also proportional directly to the bit diameter. |