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.

A guide assembly, or rip fence, supported by guides of a table saw includes a clamping apparatus having locking mechanisms located at each end of the guide assembly. Each of the locking mechanisms is independently adjustable to provide accurate and repeatable positioning of the guide assembly with respect to the table and with respect to the saw blade with self-alignment and desired force. An adjustable locking self-alignment spring provides for self-alignment of the rip fence with respect to the blade.