|
(11) | EP 1 611 983 A8 |
(12) | CORRECTED EUROPEAN PATENT APPLICATION |
published in accordance with Art. 158(3) EPC |
|
|
|
|
|||||||||||||||||||
(54) | HIGH-SPEED PROCESSING TAP |
(57) A high-speed forming tap (1) for cutting and forming a female screw by cutting edges
(E) of a screw portion (2) fed in synchronous with the rotation of a machine tool.
The high-speed forming tap is characterized in that chamfers (CF) are provided at a bevel lead (2a) of the screw part (2). The chamfers
(CF) start from the cutting edge (E) and are provided along ridgelines (R) between
a crest face (2e) and flanks, or a following flank (2c) and a leading flank (2d).
This structure enables the shape of the edges of the tap leading portion to be stably
maintained and high-speed, smooth female screw cutting with high accuracy, and provides
a tap with long life.
|