| 摘要 |
A process and apparatus for sharpening twist drill bits, for use with a rotary abrasive wheel. The apparatus has a vertical support plate connectable to a standard adjustable base. A cylindrical ring rotatably mounted in the support plate has a radial dovetailed groove on its front face. A sliding plate, with a mounting flange and hole for a chuck on its angled front face, slides in the dovetailed groove of the ring. An angled bar is mounted on the rear face of the ring, to act as an alignment pointer. Both the ring and the sliding plate each have an angled notch cut out of its front face. The two notches are adjacent to each other, and their two opposite edges are aligned when the sliding plate is centered in the ring. In use, the end of a drill bit is placed into the notches, so that the web of the drill bit can be used as a measurement to offset the position of the sliding plate from center. The drill bit is then installed in a chuck on the mounting flange, with the tip of the drip bit extending through the holes in the sliding plate and ring. The pointer is used to position the drill bit radially and axially. The ring and chuck are then caused to rotate, to grind an offset tilted cone shape on the end of the drill bit. A further development has the rotating member horizontally slidable, while restricting movement of the angle plate, to form a straight chisel edge on the drill bit.
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