| 摘要 |
PROBLEM TO BE SOLVED: To overcome, or at least relieve, the problem of a drill bit owing to its high rate of wear. SOLUTION: A tool bit includes a cylindrical body having a long axis, and its apparatus engaging end is formed at one end of the body to serve for engagement with an apparatus able to rotate the body round the long axis, and its machining end is formed at the opposite end to the apparatus engaging end. The machining end is covered with a coating layer of plasma evaporated metal carbide. At the time of service, the coated machining end is used for boring a hole in a PCG base board. COPYRIGHT: (C)2008,JPO&INPIT
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