| 摘要 |
<p>An improved thread tapping form is used to form an internal thread convolution in a member, The thread tapping form includes a plurality of projections which are disposed on a shank having a circular cross sectional configuration. Each of the thread forming projections includes a leading section which parts the material of the member to initiate formation of the flanks of the internal thread convolution. A side section of each thread forming projection presses against the flanks of the internal thread convolution to further form the flanks. A trailing section of each projection supports the side and leading sections of the projection.</p> |
