| 摘要 |
PROBLEM TO BE SOLVED: To provide a tap fastening structure and a tap fastening method capable of preventing damage to the tap caused by an overload and a tapping failure caused by an insufficient grip force during a tapping process by a turning machine or a drilling machine of a machine tool. SOLUTION: Three equally-divided thread holes are formed at the outer periphery of a tap holder 12 for gripping the tap T, and setting bolts 18, 19 are inserted. The two setting bolts are provided at all positions formed of members which are formed of hardened high-speed steel or tool steel, or at part of a portion for retaining the tap T, and at the other setting bolt, a steel ball formed of a hard member such as a bearing ball is buried and provided at a tip so as to be rotatable. Tips of the three setting bolts are made into flat forms so that the tap may be brought to linear-contact with a shank t. Besides, the shank t of the tap is supported by the two setting bolts 18, 19 formed of hard members in order to grip the tap T in a favorable state without twist, and then pressed by the setting bolt provided with the steel ball rotatable at the tip. COPYRIGHT: (C)2008,JPO&INPIT
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