| 摘要 |
PURPOSE: A drill integrally formed with a shank part is provided to simplify the manufacturing processes and to reduce the manufacturing cost by forming a flute part of the drill with metal and molding high-strength synthetic resin to the flute part. CONSTITUTION: A drill includes a flute part(3) made of tungsten and a shank part(1) integrally formed with the flute part(3). The flute part(3) has a predetermined length and is molded to the shank part(1). A predetermined portion of the flute part(3) molded to the shank part(1) is formed at an outer peripheral portion thereof with a plurality of slots(4) in order to prevent the flute part(3) from being separated from the shank part(1). The predetermined portion of the flute part(3) inserted into the shank part(1) is at least 50% of a length of the flute part(3).
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