| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling bit which does not cause the deterioration of sludge discharge performance when digging a drilling hole, and can surely and effectively draw out and collect a bit main body from the drilling hole after the drilling hole is dug up to a prescribed depth.SOLUTION: A reaming part 13 larger than a rear end in diameter is formed at a tip of a bit main body 11 which rotates around an axial line O, a drilling chip 15 is arranged at a tip of the reaming part 13, a sludge groove 17 extending to the direction of the axial line O is formed at an external periphery of the reaming part 13, and a communication groove 18 is formed at the sludge groove 17 toward the rear end from the external periphery of the reaming part 13. |
