Abstract: This invention is an attachment mountable to the underside of a router by means of which dados (grooves) may be accurately cut in a work-piece uniformly and equidistant from the previous dado without any adjustment to the attachment. The initial dado may or may not be parallel to the edge of the material.The attachment consists of two plates. The top plate has predrilled holes for fastening it to the router. There are also predrilled holes in the top plate for the router bit and for the fasteners used to bolt the two plates together. The lower plate has an elongated hole for the router bit to pass thru in the various settings. The lower plate also has four other narrower elongated holes used in fastening the two plates together in the various settings.A follower of the desired size is fastened by screws to the lower base plate to control the distance between the dado being cut and the previous dado.