Abstract: Pipe welding clamp apparatus, including a pair of clamp assemblies, one being of conventional design and the other being of a special design permitting access to the axial space between the clamp assemblies so that internal welding assemblies may be disposed partly within said axial space and partly at a location opposite said special clamp assembly from said axial space. Each welding assembly includes a relatively large welding electrode reel and an electrode feeder at said location, communicated with a torch assembly in said axial space through a flexible tube. Each torch assembly includes means for torch position adjustments angularly and radially, and includes novel means for oscillating the torch so that a wider root weld is formed which will bridge the welding gap between adjacent pipe ends in spite of torch position misalignment and in spite of irregularities in pipe alignment and welding gap width. Novel clamp locator means and wheel support means are also disclosed.