| 摘要 |
<p>A drill having a tubular shank (11) of non-circular cross-section had a body (13) of plastics material moulded round its end. This body is lodged in a metal casing (16) of circular exterior cross-section to act as holder, a key (15) or other means being provided to prevent relative rotation of the body (13) and casing (16).</p> |
