摘要 |
<p>A drill bit (10) is provided with a cylindrical body portion (24) fabricated from a plastic material. The body portion is fastened in concentric, end to end relation to a cylindrical cutter (12) fabricated from a metallic material and having an array of cutting elements (16) 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.</p> |