| 摘要 |
<p>The swarf guard for a twist drill consists of a variable-length tube section (1) with one end (2) detachably fixed to the drill, and the other end (4) extending beyond the end of the bit. The tube section may be made of resilient material, or it may be concertina-like or telescopic. Pref, it is transparent and wider at the end adjacent to the bit, with end surfaces of sponge-like material. It may have a connecting opening (7) for a vacuum cleaner. The guard can be withdrawn to some extent to start drilling, so that the end of the bit can be seen easily. When forming vertical or downwardly sloping holes, the drillings accumulate around the bit in the tube section.</p> |
