Self centering fastener

A one-piece fastening element of synthetic material comprising a head and a relatively rigid shank adapted to be inserted in an aperture in a workpiece, said shank having a longitudinal axis and including a shank portion having a pair of transversely extending webs wherein each web has marginal edges, and a longitudinally extending web extending between and interconnecting said pair of webs, at least two axial rows of flexible lamellar radial ribs formed integrally with said shank, circumferentially offset and including a plurality of said ribs in axially spaced arrangement, each row extending radially outwardly from said longitudinal web and from between respective marginal edges of said pair of webs, whereby the marginal edges of said pair of webs are adapted to generally centrally locate the longitudinal axis of said shank relative to the center of said aperture and said ribs are adapted to engage said workpiece about the periphery of said aperture to secure said fastening element relative thereto.