Abstract: For removable attachment to a sheet metal drain trough or gutter a cutting fixture which has rigid template portion having an opening therethrough defining the size and shape of a hole to be cut through the bottom of the gutter. Pivotable brackets extending from opposite edge portions of the template adapted to clampingly engage the upper side wall portions of the gutter to hold the template snugly against the bottom of the gutter and impart rigidity to the gutter for cutting and is particularly adapted for use with a router. The invention also includes a method of using the fixture in making cutouts in drain troughs for installing downspout tubing.