How to Build a Jig to Router a Stringer

Read your area's building code to find the correct riser height and tread width to use.

Place a piece of 2-foot-by-2-foot-by-1/2-inch plywood on a flat surface. Lay a framing square on the plywood, and mark the correct riser and tread dimensions. Mark the thickness of both the riser and the tread on the plywood. The completed marks should look like the outline of the ends of the tread and riser.

Put on safety glasses. Insert a 1/2-inch paddle bit into an electric drill, and drill a 1/2-inch hole into the plywood inside the marks you made. The hole will enable a jigsaw blade to enter the outline of the tread and riser marks.

Place a jigsaw on the plywood with the jigsaw blade protruding into the 1/2-inch hole you drilled. Cut inside the lines for the riser and tread.

Place the plywood on a 2-by-12-inch stringer at the location where it will be routed. Mark each side of the stringer on the plywood to indicate where you will place 3/4-inch hardwood pieces.

Cut one 3/4-by-2-by-48-inch piece of hardwood into two pieces that are each 3/4 by 2 by 24 inches.

Place one hardwood piece one each side of the stringer. Insert 1-inch drywall screws through the plywood and into the hardwood pieces along the marks that you made to indicate the stringer's sides. The hardwood pieces act as guides for the jig to slide easily along the stringer.