| 摘要 |
<p>The tensile strength of first fastening member (27) is greater than that of second fastening member (25). In the event of repetition of insertion/deinsertion of cutting tool (23), deterioration would occur on the second fastening member (25) with less tensile strength. However, this can be coped with by replacing the second fastening member (25), so that breakage of the first fastening member (27) can be prevented, thereby reducing the frequency of replacement of oscillator (82). As the material of the first fastening member (27), use can be made of high speed steel, cemented carbide, SCM steel (chromium molybdenum steel), etc. As the material of the second fastening member (25), use can be made of cemented carbide, SCM steel (chromium molybdenum steel), etc.</p> |
