| 摘要 |
The screw (11) has a thread (13) arranged in areas over a circumference of a shaft (12), and a helix portion (14) provided in the thread. Cutting bodies (26) are arranged in recesses of the thread, where the cutting bodies are made of material having hardness greater than hardness of the thread. Longitudinal extensions of the cutting bodies are oriented along the helix portion so that longitudinal axes form an angle of specific degrees with respective to tangent of the helix portion. |
