| 摘要 |
PURPOSE: A female screw cutting tap with desired portion being broken is used in cutting or plastic working of a female screw. The female screw cutting tap is provided to allow a desired portion of the tap to be broken in a desired shape at a desired section if the tap is broken during tapping and also to simply remove a piece of the tap broken and embedded in a hole by any suitable tool. CONSTITUTION: A female screw cutting tap with desired portion being broken comprises a contact section(77) for cutting a workpiece(99), a thread section(44) for guiding the contact section(77), a groove(55) for discharging chips produced at the contact section(77), a shank(11) for supporting the contact section(77) and the thread section(44), a square angled section(22a) for engaging the tap to a power source, wherein a section between the thread section(44) and the shank(11) is provided with a notch(33) with a desired depth to have a smaller outer diameter than that of the shank(11) and a square angled section(22b) like as the square angled section(22a) is formed on a portion in a direction from the notch(33) to the thread section(44). If torque reaches to a predetermined value, the notch(33) is broken. When the tap is broken and embedded in a hole of the workpiece(99), the broken tap is easily removed by engaging any suitable tool to the square angled section(22b).
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