A closure designed to fit over the end of a split or tubular rivet shank and into which the shank end is crimped in assembly. It provides greater strength and gives the appearance of a solid rivet at the clinched end. The closure may have a knurled shank and a head with its bottom recessed to fit over a hollow rivet head. It is designed to be pressed or driven through the head of a hollow rivet when a closed assembly is required.