Abstract: A tacking rivet has a shaft and a head with a longitudinal bore through the haft and through the head. The head forms a rim extending radially outwardly and the rim or head has a divider which divides the head and/or rim into at least two portions. The divider may, for example, be a slot or recess or indentation.

Abstract: A shock and vibration-proof fastener of general application and particularly suitable to hold dual wheels demountably assembled to a cargo vehicle hub. The fastener is designed to isolate the threads thereof from radial and torsion stresses utilizing a split collet encircling the shank of the fastener with its periphery converging toward the collet ends at angles of the order of 4 to 1 relative to the collet axis and having a nesting interference fit with a similarly tapered bore through the parts or wheels to be clamped together. The fastener shank has a threaded well in one end mateable with a cap screw having a self-aligning conical surface on the underside of its head engaging the rim edge of a loose fitting washer. The self-aligning surfaces are preferably provided with a ring of teeth and notches interengaging along helical surfaces having a pitch substantially greater than that of the fastener threads.