Do-It-Yourself Deck Railing Posts

Measure and mark the outer edge of the deck frame where you intend to install the posts. Count the number of posts that will be needed to complete the railing. Set the chop saw to make 90-degree cuts. Measure, mark and trim the 4-by-4-inch posts to 38 inches in length.

Set the circular saw to make 90-degree cuts, 1 inch deep. Use a carpenter's square and a pencil to mark a perpendicular line across the post, 6 inches from its lower end. Place the post on a flat surface. Use the circular saw to cut a groove across the post on the line. Position the saw blade 1/4 to 1/2 inch from the first cut, closer to the lower end of the post. Cut another groove across the post, parallel to the first groove. Continue cutting parallel grooves until you reach the lower end of the post. Repeat to cut grooves in the remaining posts.

Turn the post so the grooves are vertical. Position the tip of the wood chisel against the bottom of the grooves, parallel to the end of the post. Strike the end of the chisel's handle with a hammer to chip away all of the grooved wood, leaving a smooth 1 inch deep notch, 6 inches long. Repeat to notch the lower ends of the remaining posts.

Position the first post on the edge of the deck frame, aligned to the positioning mark on the frame. Rest the top of the notch on the edge of the frame. Mark the center of the notched portion of the post 2 inches and 4 inches from its lower end. Drill a pilot hole through the post at the top mark. Drill about half an inch into the frame. Place a washer onto a 1/4-inch lag screw. Insert the tip of the screw into the pilot hole. Tighten the screw with a socket wrench. Do not over-tighten.

Place a carpenter's square against the side of the post and top edge of the deck frame. Adjust the position of the post, if necessary, so it is perpendicular to the frame. Drill a pilot hole through the bottom mark on the post, into the frame. Using a lag screw, washer and socket wrench, attach the post at the bottom. Tighten both screws to hold the post securely. Repeat to install the remaining posts.