A fluid fitting includes a nut, a sleeve, and a union. The union and the nut may include corresponding stops. Corresponding stops may engage with each other when the nut is sufficiently connected with the union. A method of designing a fluid fitting including a union may include determining a gauge diameter of the union, determining a plane perpendicular to an axis of rotation of the union that includes a center point of the gauge diameter, determining a point of intersection of threads of the union with the perpendicular plane, and/or determining a position of a stop according to an angle from the point of intersection.