Kyushu Tlo Company, Limited

Teruie Takemasu

Hiroshi Miyahara

A method and apparatus for manufacturing a bolt capable of mass-producing a multiple screw bolt such as a so-called double screw bolt at a low unit price, and a thread rolling die for use therein. The apparatus for manufacturing a bolt comprises a pair of thread rolling dies () which are arranged opposite to each other at a predetermined interval, and a bolt supporting unit () which supports a cylindrical bolt material () in a predetermined position. The thread rolling dies () are provided with a transfer pattern () having a coarse thread portion () which is part of a coarse thread formed by developing a coarse screw, and projections () which are part of a fine thread () formed by developing a fine screw as shown by an imaginary line (), the fine thread () being formed cyclically on a root portion () of the coarse thread according to a phase shift between the fine thread and the coarse thread.

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Fukuoka, Japan

Teruie Takemasu