Often called "dimple dies", flared hole dies are used in sheet-metal fabrications to provide rigidity and strength to flat, unsupported panels

STOP TRYING TO JAM A NUT THAT WON'T STAY!!!! ELIMINATE IT.
Rod End Receivers - Round
Material Spec: 4140 N Chromoly Steel Includes Grade 8 Bolt, metal locknut and 2 AN washers Welds into stock tubing sizes. Cinch bolt maintains high clamping force