| 摘要 |
PURPOSE:To prevent vibration by protruding a cutting blade at the tip of a thin cylinder, providing a recess which discharges chips to the outside of a work at the time of initial machining and stores chips while the machining proceeds, and further providing a slant rear edge in front of the cutting blade section. CONSTITUTION:A shaft 12 is protruded behind a cylinder 11, a cutting blade section 13 is protruded at two tip edges, and a recess 16 is formed adjacently to the cutting blade section 13. In addition, a rear edge 17 is formed so as to be extended slantly toward the front interior in the rotating direction from the cutting blade section 13. This circular boring blade 10 is supported by a chuck 21 of a drilling machine or the like and is rotated and pressed to a work 22 such as a wood plate, then a hole is bored. In this case, chips are discharged to the outside of the work through a recess 16 at the time of initial machining and are stored in the recess 16 when the cylinder 11 enters the work. According to this constitution, the cutting blade section 13 can be sufficiently firmly supported, thus no vibration occurs on the cutting blade section or the like even if the cylinder 11 is made thin. |
