A Simi-Tubular Rivet has a hollow shank which is equal or greater than112% of the shank diameter. These are a good fastener to quickly join 2 or more pieces together. The tubular part of the rivet squeezed with an arbor press opens the back end and clamps down on the material be fastened together. The end of the rivet must be long enough to pass through the work piece(s) with enough shank left over to create the fit needed. The tightness is determined by the amount of force applied at installation.