Alignment and assembly tool for very large diameter cylinders

An alignment and assembly tool is disclosed for aligning the ends of two very large cylinders so that the ends may be welded with a cylindrical strengthening section inserted between the cylinders and aligned and welded into the joint. The tool has a U-shaped main body with a horizontal top section and two legs, which are attached to the ends of the top section and extend outward and downward. Horizontal bottom sections extend outward from the bottoms of two of the legs. The tool has one inner jackscrew and one outer jackscrew on each side of its center, extending downward from the top section. Each of the two bottom sections has an attached side clamp for clamping the alignment tool to two opposing skin stringers of two of the cylinders. The jackscrews are adjusted to bring the edges of a tee ring into precise alignment with the ends of the two large cylinders so that both joints may be welded around their circumference.