| 摘要 |
A drill bit is provided with a cylindrical body portion fabricated from a plastic material. The body portion is fastened in concentric, end to end relation to a cylindrical cutter fabricated from a metallic material and having an array of cutting elements disposed thereon. The body portion and cutter are preferably tubular, wherein the cutting elements are disposed in an annular array, to facilitate core or crown drilling operations. The wall thickness of the tubular body portion may be increased relative that of the cutter to compensate for wear during drilling. The tubular body portions also may fabricated from a composite polymer including wear resistant particles, whiskers, fibers and the like disposed on inner and outer surfaces of the polymer body, or dispersed throughout the body. |
