Abstract: An improved nut fastener is utilize with a back-up plate to perfect a bolted flange joint. The fastener includes a cage having a planar body affixed to the back-up plate in bearing engagement with a surface thereof. Opposed sides upstanding from the cage body are configured to loosely capture a spherical faced washer, a spherical faced nut, and a nut anti-torque collar in self-aligning relation with a joint bolt hole. An extension of either the cage body or the collar is configured to engage the back-up plate in a manner to inhibit rotation of the cage.