Abstract: A rolling die is provided for forming a rod member with a ball portion. The rolling die includes a first die member and a second die member facing the first die member. Each of the first die member and the second die member has a process surface. The process surface has a start forming portion having a process tooth configured to bite the rod member and an arc surface portion proximate the process tooth, an intermediate forming portion having the process tooth and a curved surface proximate the process tooth, the curved surfaced being configured to press the rod member to form an arched shape, and a finish forming portion having the process tooth and a hemispheric groove configured to press the rod member into the arched shape to form the ball portion.

Abstract: A rolling die is provided for forming a rod member with a ball portion. The rolling die includes a first die member and a second die member facing the first die member. Each of the first die member and the second die member has a process surface. The process surface has a start forming portion having a process tooth configured to bite the rod member and an arc surface portion proximate the process tooth, an intermediate forming portion having the process tooth and a curved surface proximate the process tooth, the curved surfaced being configured to press the rod member to form an arched shape, and a finish forming portion having the process tooth and a hemispheric groove configured to press the rod member into the arched shape to form the ball portion.

Abstract: A rolling die is provided. The rolling die includes a bite portion having bite processing teeth at a bite starting point for a workpiece, and a finishing portion having finishing processing teeth. The bite processing teeth at the starting point in the bite portion have lower tooth height than the finishing processing teeth in the finishing portion. The bite processing teeth have a larger tooth tip angle and a larger trough angle than the finishing processing teeth.

Abstract: The present invention relates to a reciprocating type thread rolling apparatus and comprises a ram reciprocated by a crank shaft and fixing to one side thereof at least two moving dies, the other side of the ram being disposed along a single thread rolling pressure bearing block, and stationary dies adapted to pair with the moving dies for thread rolling, the stationary dies being the same in number as that of the moving dies and disposed to be opposite to the moving dies.

Abstract: A method of manufacturing a connector bolt includes the steps of forming axial grooves on a part of the shank of the connector bolt, and then simultaneously performing a rolling process for thread formation around the shank part with the axial grooves formed thereon with a rolling tool and a different rolling process around a part of the shank without the axial grooves with a different rolling tool.