| 摘要 |
PCT No. PCT/SU80/00105 Sec. 371 Date Jul. 22, 1981 Sec. 102(e) Date Jul. 22, 1981 PCT Filed Jun. 26, 1980 PCT Pub. No. WO81/01672 PCT Pub. Date Jun. 25, 1981.The tap comprises a groove forming portion (1) with a shank (2) having a thread forming portion (3) such that the thread pitch thereof is equal to that of the groove forming portion (1), the crests of the thread forming portion (3) being axially displaced from those of the groove forming portion (1). The thread forming portion (3) is threadedly positioned behind the groove forming portion (1) for axial movement on the shank (2), the movement thereof being limited by a stop (4) arranged on the shank. |
