MACHINING HEAD REPLACEMENT TYPE ROTARY TOOL, HOLDER, AND MACHINING HEAD

PROBLEM TO BE SOLVED: To easily remove and replace a machining head while maintaining a predetermined installation strength, in a machining head replacement type rotary tool in which a holder and the machining head are integrally connected to each other by a fastening male screw and a fastening female screw. SOLUTION: The fastening male screw 18 and the fastening female screw 20 are comprised of a buttress screw in which a flank angle α of a trailing side flank 52 is smaller than a flank angle β of a leading side flank 54. Therefore, if they are thermally expanded when milling is carried out by the machining head 14, their respective trailing side flanks 52 are less liable to strongly adhere to each other and cause deposition. The deposition of the leading side flanks 54 on the opposite side is also suppressed, thereby facilitating a removal operation when replacing the machining head 14. On that occasion, the flank angles β of the leading side flanks 54 are relatively large, thereby maintaining the predetermined installation strength. COPYRIGHT: (C)2011,JPO&INPIT