Abstract: A versatile router guide apparatus or kit is disclosed comprising a pair of side rails and a pair of headpieces, which may be releasably secured together to form a "modified box type" router guide. When so secured the guide may be clamped to a workpiece between the headpieces and a router moved in the guide to form transverse dadoes or cuts therein. Bridges are also provided that may be temporarily fixed across the rails at strategic positions therealong, and projecting router stops attached to headpieces so that precise interrupted cuts or dadoes can be made in the workpiece. Further, the router may be releasably positioned within the guide, at one location relative to the guide and the guide unclamped and moved longitudinally along the workpiece to make longitudinal cuts or grooves therein.