| 摘要 |
PROBLEM TO BE SOLVED: To provide manufacture of a screw decreased in screwing torque and a rolling dice used in the manufacturing method. SOLUTION: A rod-form work is rolled in a state to be nipped between two rolling dice each having a groove for forming a male screw and a male screw is formed on a work. In the so described manufacture of a work, a plurality of protrusion ribs in a direction crossing a groove are formed on the terminal end part of the groove for forming one male screw and a plurality of recessed parts 10 are formed in a screw thread at the final stage of formation of a screw thread by the protrusion. The screw thread 7 is formed in a saw tooth-form state, burrs and flash are generated and since the texture of wood is cut thereby, and screwing torque is decreased.
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