An apparatus for rotation of a structural beam during fabrication thereof comprises spaced mounting members, each mounting member including a base frame and a circular support bracket supported for rotation by spaced rollers mounted on said base frame. At least one of the spaced rollers includes a drive mechanism to rotate the support brackets with a beam located therein. Each support bracket comprises a beam clamp mechanism with a stationary portion and a movable portion pivotably mounted thereto to form opposable jaws to receivably locate said beam therein.