Power spring configurations for a spring energized fastening device includes a compact double torsion power spring and two opposed compact single torsion springs. Simplified structures to hold the springs in a stable pre-loaded position are disclosed. Each coil has forward extending arms including an angled portion and forward vertically coincident portions. The double torsion spring has a self-locking crossing geometry to hold a pre-loaded rest position. The opposed two springs have a bridge and a mandrel to hold the rest position. A lever presses arms of the spring between a striker and the coil including a compact nesting condition. A tab of the striker extends forward to provide a release edge and a positioning torque bias upon the striker.