Abstract: A guide bar is detachably clamped to the panel being cut with a pair of guide plates extending therefrom and registering upon the line to be cut. The guide bar is provided with a longitudinally extending slot or groove into which is engageable a guide block for longitudinal movement therealong. A power saw is detachably securable to the guide block which guides the saw blade along the line to be cut. The guide bar includes an underside clamp and spacer bar which spaces the panel above the supporting surface sufficient to give clearance to the underside of the saw blade as the panel is being cut.