An assembly that includes a wedge and mandrel that share an axis of rotation and can be rotated independently or simultaneously to stow or deploy slit-tube longerons. A wedge is crescent shaped, with a height that increases along an outer perimeter as the arc of the crescent is traversed from a first end to a second end. The changing height of the wedge allows a slit-tube longeron to be flattened for stowage or can be disengaged to allow the tube to curl up for deployment.