Abstract: Apparatus for guiding a small router head along either straight paths or arcs of circles, for cutting sheet metal printing plates to desired outlines. The operator may guide the router over the same path several times, successively increasing the depth of cut until it is cut through. In the preferred form for cutting along straight lines, a guide rod is supported between two offset heads that attach to the work by suction cups. A short square-section mounting bar rides in a ball bushing along the guide rod. A router head assembly clamps detachably to the bar. For cutting arcs of circles a pair of radius rods is carried adjustably in a rotatable center head that attaches to the workpiece with a suction cup. A second mounting bar connects the free ends of the radius rods; the same router assembly may be detached and clamped to this bar.