Abstract: A guide rod is clamped at each end across a board placed flat on a workbench or comprising the workbench. Clamps on each end of the board have extensions with sleeves on their upper ends for receiving the guide rods, as well as flat bars which square against the edges of the board, such that the guide rod will be perpendicular to the sides of the board. In a preferred embodiment, the upper sleeves are pivotable and the clamps are provided with a protractor and square such that the guide rod can be placed across the board at an angle other than perpendicular. A guide carriage comprising a yoke fitting around the guide rod is slideably disposed thereon by means of four wheels, two at each end on either side. The guide carriage has a short rod transversely slideably disposed to the guide rod with a set screw for fixing the extension of the short rod at a given distance from the guide rod.