Abstract: A clamp encircles the outer rim of an out-of-round tubular pipe to reform the cross-section of same into one that is substantially round, the clamp including a ring frame, a plurality of pivotally mounted roller assemblies each having a roller to engage the pipe rim, and drive means for pivoting the roller assemblies such that the rollers simultaneously rotate to contract radially inwardly or outwardly relative to a circle defining the locus of pivot axes, the rollers describing first and second circles and being adapted to close into a circle having a diameter sized to engage the pipe, when inserted therein. The clamp can include multiple sets of separately adjustable roller assemblies.