Patent ID: 8024848

Claim:
A double-action clinching method, comprising: establishing a first layer on a second layer, the first layer having less ductility than the second layer; securing the first and second layers between a punch and a clinching punch of a double-action clinching tool such that: i) a support of the tool receives a portion of a surface of the second layer, and ii) the clinching punch slidably positioned in the support is adjacent to an other portion of the surface of the second layer; and the punch, positioned opposed to the clinching punch, is adjacent a portion of a surface of the first layer, wherein the punch has a first diameter, and the clinching punch has a second diameter that is smaller than the first diameter; pressing the punch into the portion of the surface of the first layer, thereby forming an aperture through the first layer; and then pressing the clinching punch into the other portion of the surface of the second layer in a direction opposite to the pressing of the punch, thereby forcing at least a portion of the second layer into the aperture and forming at least a flush-back joint with micro-interlocking between a side wall of the aperture and the at least the portion of a second layer.