How to build an obelisk Use these instructions to create a beautiful garden tower Materials list Full article Pinterest Cut the tongue Mark the cut post top for a tongue. The tongue should be 33⁄8 inches long and wider at its base than at its shoulders. Make it 1 inch wide at the base, tapering to ½ inch at the shoulders.Set a circular saw to make a cut 1½ inches deep, and cut the line at the top of the shoulder. Then set the saw to full depth and cut the other (tapered) line, taking care not to cut too far.Flip the post over and cut from the other side, then finish the cut using a handsaw. Cut the other side of the tongue in the same way. Attach the legs he tops of the legs are cut on a compound angle ― that is, the saw blade is set at an angle, and it runs across the piece at an angle as well. The magic number is 6 degrees. Make the cuts 6 degrees off square (that is, either 96 degrees or 84 degrees, depending on how you hold the square) with the blade also tilted 6 degrees.Position the legs against the post tongue and test to see that the leg bottoms are fairly close to 22 inches apart; adjust the angles if needed.Drill pilot holes and attach the legs to the post top with 2-inch screws. Install the spreaders Cut the spreaders to length, angling the ends at 6 degrees off square so they will follow the lines of the spread-apart legs. Position the spreaders about 10 inches above the bottom of the legs.Drill pilot holes and screw the spreaders to the legs. You may need to flex the legs a little to make the spreaders fit. Attach the inner pieces Cut the crosspieces, angling the ends at 6 degrees off square. Space them 15 inches apart on the legs, starting from the top of the spreaders.Drill countersunk pilot holes and screw the crosspieces to the legs with 1¼-inch screws. Weave the verticals over and under the crosspieces. Fasten the verticals to the post and the spreaders with 1¼-inch screws.