| 摘要 |
PROBLEM TO BE SOLVED: To provide a borer capable of boring a high finish hole on a gypsum board to which wall paper or cloth is stuck. SOLUTION: A cylindrical cutter edge 6 is fitted to a tip of a hone 4a of an ultrasonic vibrator 4 built in a housing 2 of a mechanical part. By pushing an electric source switch 9 arranged to a grip 3, electricity is applied to a supersonic oscillator 5, and the supersonic vibrator 4 and the cylindrical cutter edge 6 are vibrated at a high frequency. When the cylindrical cutter edge 6 is pushed onto the gypsum board, the cylindrical cutter edge 6 passes through and a circular hole is cut through. Since the cutter edge is vibrated at a high speed front and rear by a small amplitude, in the case where a cloth-stuck gypsum board is bored, it comes to be cleary finished with neither peeling off nor tearing the cloth. Further, an amount of generated dust is little and noise is scarecely generated.
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