Self-gauging, interference fit rivet

Claim 1

A self-gauging, interference fit rivet, comprising a. a head and a shank protruding therefrom, b. the shank having, along its length in a forward direction away from the head, a sequence of progressively reduced diameter sections, the forwardmost and smallest section to fit freely within a work bore and the rearwardmost and largest section to resists complete insertion of the rivet in the bore by interference engagement with the work surrounding the bore, c. there being an elongated first mid-section between said largest and smallest sections for centering the rivet in the bore through slight interference therewith, d. said shank largest section being capable of forced insertion relatively into the bore to enable closure of the head toward the work and to pre-stress the work around the bore, e. said smallest section of the rivet being unthreaded and sized to be upset for forming a retaining flange at the side of the work opposite the head f. and there being a second elongated mid-section between said shank largest section and said first mid-section, the first mid-section having a diameter providing less interference with the bore than is provided by the second mid-section diameter, the rivet shank largest section tapering toward said second mid-section, and there being a forwardly tapering annular step shoulder between said first and second mid-sections.