Lay the 96-inch board flat, and position a 60-inch board perpendicularly against its end. The 96-inch board should be centered on the 60-inch board, 13 ¼ inches away from each end of the 60-inch board. Screw four screws through the 60-inch board, and into the 96-inch board by first drilling four 3-inch deep, 3/8-inch counter-sink holes. Repeat this process.
Cut the ends of your 48-inch boards at a 45-degree angle. When the boards lay flat, they should resemble a trapezoid. The original length should not be altered. These are the support boards to the stand. Their 45-degree cuts will lay flat on the boards in the previous step.
Lay a 96-inch board flat, and position a 48-inch board on each side of the 96-inch board. The angled cuts should rest flat against the 96-inch board, as well as the 60-inch board. Screw two screws through each end of the 48-inch boards, and into the 96-inch and 60-inch boards to secure them. Repeat this process. These are the two sides to your stand.
Drill a 1-inch-wide, and 1-inch-deep hole in each 96-inch board. The hole should be 6 inches away from the end that is opposite the 60-inch board, on one of the sides that is flush with the 60-inch boards, and with its center 1 ¾ inches away from either side of the board.
Position the sides upright, parallel, 41 inches apart, and with the 1-inch holes facing each other. Place the metal pipe in the holes. Set the 48-inch board on top of the ends of the 96-inch boards so the corners are flush, and screw it in place. Use eight screws for this task. Use the ladder to make this easy.
Cut the ends of the 24-inch boards at a 45-degree angle. When they rest on their 2-by-24-inch side, they should resemble a trapezoid. Screw these boards to the top of the pull-up stand. Their 45-degree cuts should be flush with the top edge of the 48-inch board, and the outside edges of the 96-inch board. Use four screws for each 24-inch board. There should be two boards in the front, and two boards in the back of the stand.