Abstract: A gable clamp device for holding a brick mason's guide line while a bricked-in gable is being constructed. The gable clamp device includes of a pair of gable clamps, a pair of angle irons, and a mason's guide line. The angle irons are elongated beams having a prismatic L-shape which are adapted to be attached to the underside of a gable so that one portion of the angle iron lies flat against the underside of the gable and the other portion extends perpendicularly therefrom. The gable clamps have a line holder and a channel shaped clamping portion that allows each clamp to be attached to a gable face board or to an angle iron. When the gable clamp device is used to construct a bricked-in gable with a conventional 4.5 inch roof overhang, the gable clamps may be attached to the gable face boards. However, when the gable clamp device is used to construct a bricked-in gable with a roof overhang that is greater than 4.5 inches, the angle irons are attached to the underside of the gable about 4.