| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rock drill in which a guide sector region seen on the cross-section is enlarged and even when a hitting stress is applied, fixing force of a head to the drill is not lost and which is hardly worn. SOLUTION: In the rock drill in which at least one spiral rail 2 with a spiral shape and an insert 3 made of a hard material on which rotational and hitting stresses are at least partly applied are provided and at least one guide end edge 6 is provided on this insert, the guide end edge 6 is constituted in a shape with a sharp angleαto the axial line A of the tool. The insert is fixed on the end face 8 which is on the opposite side of the hole drilling direction of the insert 3 made of the hard material or extends in the direction intersecting at right angles in the hole drilling direction and the guide end edge 6 is smoothly made to continue to the spiral rail 2. The insert 3 made of the hard material is constituted as the head 3 or a plate made of a super-hard material.
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