| 释义 |
counterbore/kaʊntəˈbɔː(r)/1a drilled hole that has a flat-bottomed enlargement at its mouth 扩孔, 沉孔, 导孔。
1.1a drill whose bit has a uniform smaller diameter near the tip, for drilling counterbores in one operation 扩孔钻。
with obj. drill a counterbore in (an object) 在…上钻导孔。
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