| 摘要 |
PURPOSE:To prevent a chaser from tumbling so as to perform processings of threading with utmost accouracy, by covering the aperture of an insertion groove of die-head chaser with the fixed holder ring, and allowing a cam ring to slide in a holder ring. CONSTITUTION:A cylindrical die-head body 6 has a chaser insertion groove 7 at each of plural places and a chaser 8 is mounted. Open side of the chaser insertion groove 7 is covered with a holder ring 10 screwed 11 to the body 6. The cam ring 16 which moves the chaser 8 back and forth is inserted, allowing free sliding, in the fitting groove 13 formed in the holder ring 10. The fixed holder ring 10 preventing the chaser from tumbling improves accuracy of processings of threading. |
