| 摘要 |
<p>The invention relates to a drill bushing for engagement with a drilling steel, wherein said drill bushing (2) has contact surfaces (4) for contact with a drilling steel (1) , said contact surfaces (4) having interior, inwards curved shapes, whereby edge abutment of a drilling steel (1) against said contact surfaces (4) is avoided. By way of the invention, a better wear picture is obtained for the shank of a drilling steel.</p> |
