I shorten the time it takes to rout dadoes with a simple jig made from acrylic.A small, 6-in.x 24-in.piece will do.Mark the point where your router base will ride against the straightedge. Then, measure the exact distance from that point to the center of your router bit (“A”in the photo). Mark that distance in from the long edge of your acrylic rectangle.Use a sharp utility knife to score a line exactly parallel to that edge. Then, take a red, fine-point felt-tip pen and run it along the score to create a cursor.
To cut dadoes on your cabinet side, lay out the centerlines of each dado. Then, line up the red line on the acrylic with the dado centerline on the cabinet. Butt your straightedge to the acrylic and clamp it in place. Bingo! You’re ready to rout.