| 摘要 |
A form tap for tapping an article may include a longitudinal shank having a mounting end opposite a tip, the shank having a shank length, and a thread portion with a plurality of threads for engaging a surface of the article. The thread portion includes a first region, a second region and a third region. The form tap includes a plurality of lobes extending though the first and second regions from the tip to the second region end, the lobes being spaced circumferentially around the shank and lying on a crest circumference. Each lobe may be disposed between respective first and second convex relief portions and each relief portion may be spaced radially inward from the crest circumference. Each lobe has a lobe width, the lobe width at the second region end being greater than the lobe width at the tip. The third region is free of lobes. |
