Abstract: A portable saw assembly for use in making square cuts in metal structural components. The portable saw assembly includes a clamping system to hold a work piece in a fixed position with respect to the rotating saw blade and the saw blade is constrained for movement toward and away from the work piece along a specific prescribed path that assures that the saw blade will encounter and then cut the work piece at a right angle with respect to the longitudinal axis of the work piece. Thus, the portable saw assembly can be located on site of the construction and yet can be readily and easily used to cut the structural component along a square cut to facilitate the assembly of the ultimate structure. The clamping system includes clamping inserts to accommodate different sizes and geometric shapes of work pieces while still assuring a square cut thereof.