| 摘要 |
PROBLEM TO BE SOLVED: To make a cutting head reliably firmly fixed to a tool body, and enhance drilling accuracy and a tool life. SOLUTION: A cutting head part 5 provided with a cutting edge 8 is detachably fitted to a tool body 2. The engagement part of the cutting head part 5 is equipped with connecting surfaces provided respectively on the confronting sides of axially protruding shaft part 15 and a differently leveled part provided on its outer periphery. The receiving parts of the tool body 2 are equipped with abutting surfaces formed face to face in a recessed part 22 and engaged with respective connecting surfaces of the shaft part, and a receiving step part provided on its outside to transmit turning force by being fitted to the differently leveled part 18. A slit part 26 to split a pair of the abutting surfaces in the recessed part 22 of the tool body is provided. A screw hole passing through the slit part 26 of the tool body in the diameter direction is formed, and the cutting head 5 is firmly fixed to the tool body 2 by fastening the fastening bolt 30 in the screw hole.
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