Lightweight, compact, threaded fastener and thread rolling die for making same

摘要

The present invention provides an improved, lightweight, compact threaded fastener that has a relatively shortened transition thread rollout zone between the grip of the fastener and the threaded shank of the fastener. This transition zone is shortened due to the fact that the runout (or inner end) of the rolled thread on the fastener extends no more than one-third the circumference of the rolled thread at its pitch diameter. The short runout of the rolled thread does not compromise the strength of the fastener, because the runout does not have a relatively abrupt transition. Instead, the depth of the runout of the rolled thread of the fastener gradually decreases along its length from a depth equal to the uniform depth of the rolled thread throughout the length of the threaded shaft of the fastener to no depth at the very end of the runout. The invention further provides a pair of thread rolling dies for producing such an improved, lightweight, compact threaded fastener.