| 摘要 |
<p>A drill steel-chuck assembly which includes a drill steel (26) which has a plurality of faces (56-66) and opposite ends. The drill steel has one portion (74) adjacent one of the opposite ends thereof and an intermediate (76) portion spaced apart from the one portion. The drill steel further has one transition portion (78) between the one portion and the intermediate portion so as to join the one portion and the intermediate portion. The one portion of the drill steel presents a first orientation of the faces. The intermediate portion of the drill steel presents a second orientation of the faces. The one transition portion (78) of the drill steel presents a twisted orientation of the faces comprising a generally constant twist of the faces from the first orientation of the one portion to the second orientation of the intermediate portion. There is a chuck (26) for attachment to the drill steel through engagement with the transition portion of the drill steel.</p> |
