| 摘要 |
A method is disclosed of manufacturing a thread forming screw with a constant diameter helical screw thread and lead-in threads having a plurality of sharp crests and intermediate relief concave areas. The method includes the steps of forcing a cylindrical wire into a die to form on a distal end of the wire a plurality of longitudinally extending ribs spaced from each other by reduced diameter cylindrical portions. The distal end is rolled between tapered thread sections of a die set to taper the distal end and to form the lead-in threads with sharp crested lobes and intermediate relief areas while the constant diameter helical screw thread is also being formed by the die set.
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