| 摘要 |
There is disclosed a hand tool for drilling or performing other rotational operations on a work piece which is specially adapted for one-hand operation in that it consists of a small handle in which there is rotatably mounted a quill; the quill extends a sufficient distance from the front of the handle to permit it to be rotated between the thumb and forefinger while the handle is held in the palm of the hand with the other three fingers; a gripping surface is provided on the extending portion of the quill, and the quill is arranged to hold concentrically therewith a drill, tap or other tool which may be pressfit or otherwise secured in the quill. In one embodiment the drill or other twist tool is removably secured in the end of the quill by means of a tapered dart fitting a frog with a matching taper in the end of the quill. The quill is preferably removably held in the handle by a magnet or a ball-socket detent; with magnet retention a hard steel ball is preferably interposed between the end of the quill and the back of the handle to act as a thrust bearing, and guide means inside the handle guide the rear end of the quill to engage the bearing and for proper retention by the magnet or other detent mechanism. A substantially closed magnetic flux path is provided from the end of the quill through a portion of its length to the case of the handle and back through the handle to the portion thereof adjacent the end of the quill.
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