Abstract: An apparatus for making dovetail cuts along the corner of a wooden box includes a frame and a pair of elongated posts movably mounted with respect to the frame, extending away from the frame and in indexing plate member mounted at the opposite end of the posts from the frame so that the posts extend from the indexing member at generally right angles thereto. The indexing member can be fixed relative to the posts and the frame includes a router guide member having a recessed portion defined by two intersecting flat surfaces that meet at a longitudinal common line parallel to the posts, and the recess registers with the wooden box workpiece corner during use. The flat surface portion of the frame carriers a guide slot with a linear axis that extends transversely with respect to the posts and at generally right angles to the common line. The guide slot can be fixed relative to the fence and the posts and the entire assembly can be secured to a wooden box-like workpiece structure to be cut, in a clamping fashion.