| 摘要 |
PURPOSE:To prevent increase of frictional progress of a margin part compared with that of a cutting blade, by a method wherein a rigid layer, e.g. TiC, TiN, TiCN, is formed on the margin part of a tool body, and the diameter on a rotation locus of the cutting blade is made approximately equal to that of the margin part. CONSTITUTION:A cutting blade tip 3 formed by a diamond sintered substance is soldered to the tip wall part in a rotation direction of a chip discharge groove 2. Lines 4 of projection are formed on the tip outer peripheral part of a tool body 1 so that they are positioned at a middle part in a rotation direction between cutting blades 3a nd 3a. The surface of the tool body 1 containing a margin part 5 is covered with a rigid layer, e.g. TiC, TiN, TiCN. The diameter of the margin part 5 is set to a value approximately equal to that of the cutting blade 3. This constitution enables prevention of extreme increase wear progress of the margin part 5 compared with that of wear of the cutting blade 3a, and enables prevention of the occurrence of poor machining due to a difference between the two diameters.
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