Abstract: A high capacity single coil strip accumulator for transient storage of longitudinally advancing metallic or other strip material usually supplied in coils which must be welded end-to-end to form a continuous web which is to be fed at uninterrupted speed to downstream processing equipment, e.g., annealing.The single revolving accumulator coil is characterized by a variable number of convolutions and variable inner and outer diameters, with provision for continuously paying out of strip from its outer convolution, while intermittently adding new strip to its inner convolution. An independently rotatable cage with an axially locatable uncoiler for paying-off strip from a supply coil to said inner convolution has affixed thereto a joining device such as a butt welder, in the path of the strip from the uncoiler to the inner convolution.