| 摘要 |
PROBLEM TO BE SOLVED: To realize deep hole machining in which a hole depth compared with a diameter is up to 20 by a drill made of superhard alloy. SOLUTION: A method drill 1 in which a body part 2 and a shank 3 are integrated is formed by a cemented carbide alloy with excellent toughness. A cross section area at a rear side area 2b is made smaller than the cross section area of a tip end side area 2a of the body part making a cross section varying point A as a border and the length of the area 2a is preferably set to L/5-L/4. The flexure caused by a load at the time of cutting is generated at the area 2b. COPYRIGHT: (C)2004,JPO
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