Abstract: This invention provides a portable rotary saw having auxiliary means settable to select, define and control various cutting planes for the saw in relation to a top and/or side surface of the piece to be cut. Given, for example, a long heavy work piece of uniform length, width and depth, mounted fixedly in a flat condition on two or more sawhorses, auxiliary saw control means can be set to cause the saw blade to cut in a plane at right angles to the upper face of the work piece and either directly lengthwise, directly crosswise, or at any desired oblique angle across the work piece. Additionally or alternatively, the saw may be set to cut through the work piece on an unrestricted variety of bevels in any of the directions referred to. A track which is carried by the saw may be set on the work piece to guide the saw in a path parallel to a side face of the work piece or in any desired direction relative to such face.