METHOD OF PRODUCING LEFT-RIGHT SCREW

摘要

[PROBLEMS] A method of producing a left-right screw by inexpensive thread rolling process, where the effective diameter of both left and right screws satisfies the value specified by the standard. [MEANS FOR SOLVING PROBLEMS] When a first screw thread and a second screw thread are simultaneously rolled by rolling a screw material on a dice where a first edge for forming the first screw thread and a second edge for forming the second screw thread are formed on the same surface, the screw material has a smaller diameter than a screw material used for rolling only the first screw thread.