For use upon machinery in a wood shop or any industrial facility where it is desired to operate upon an object's unmarked centerline, such as with a powered saw table, drill press or any other apparatus required for the task: The sine and cosine of a triangle—are used to assure that as a certain component is moved a given distance, a guide fence is moved transversely just a fraction of that distance—preferably one-half—away from or toward the task performing instrument—a saw blade, drill bit or other operable tool. Thus, if the distance moved by the component equals the width of the piece to be worked upon, where the trigonometric sine is such that the guide fence is moved half that distance, given certain further adjustment, the task performing instrument is caused to operate precisely upon the piece's centerline, represented by one-half its width.

The invention relates to a machine-tool, especially a circular saw bench. The machine-tool has a clamping device that can be moved with the work piece in an advancing direction and which is guided at a certain height in relation to the workbench. The clamping device is used to support the work piece, in a carrying manner, in the region of the clamping device, in relation to the workbench.

The invention relates to a cutting system with a cutting machine for cutting sheet-like, stacked material and with an alignment device, which can be manually manipulated, for manually laterally aligning the material on a flat surface of the alignment device, wherein the alignment device can be placed on a table of the cutting machine, which table serves to receive the material, wherein the cutting machine has an electrical machine controller for functions of the cutting machine. In the case of a cutting system of this kind, it is provided that the alignment device has electrical components, and the electrical machine controller of the cutting machine can be actuated by means of the alignment device.

A plastic knife is provided comprising a handle, a blade, and a cutting edge. The blade may include a first surface and an opposite second surface, and integrally formed with and extending longitudinally from the handle. The cutting edge may be formed along one edge of the blade, the cutting edge comprising: (a) a first plurality of teeth integrally connected to and extending from the first surface, each tooth in the first plurality of teeth separated by a first concave groove; and (b) a second plurality of teeth integrally connected to and extending from the second surface, each tooth in the second plurality of teeth separated by a second concave groove. The first plurality of teeth and the second plurality of teeth may be integrally formed together while teeth in the first plurality of teeth and teeth in the second plurality of teeth are offset by a distance.