Mark the wooden or fiberglass bar using the measuring tape and pencil at 24, 48, 56, 64, 72, 80, 85, 90, 95, 100, 105, 110, and 115 inches from one end of the pipe. Run electric tape around each mark so that the leading edge of the tape aligns with each mark. Cut the bar into sections along the marks using the hand saw. This should leave you with two 24-inch, four 8-inch and eight 5-inch sections.
Apply primer and glue to the elbow pieces and glue to the four 8-inch sections of the bar to form the legs the bars will stand on. Prime and glue these sections to the ends of the two 24-inch sections of the bar. These will be the tops of the uneven bars. Secure a T-cap onto the end of each one. This will allow you to install a parallel section of PVC pipe between each set of bars to set the correct distance between the bars.
Prime and glue the 5-inch sections of the bar to the four remaining T-caps. Then prime and glue the end caps to each of the four T-caps.
Take your 4.6 and 7.24 lengths of PVC pipe and glue each set of pipes to the top part of the uneven bars at the "legs" on the top structure, so that one set of bars is attached to the 4.6-feet sections of PVC pipe, and the other set of bars is attached to the 7.24-feet sections of PVC pipe.
Prime and glue the two 4.6 feet sections of PVC pipe to the T-caps at the ends of both top sets of bars. These sections will run parallel to each other and perpendicular to the tops of the bars. They will set the distance between the bars at 4.6 feet or approximately 150 centimeters apart.
Glue each T-cap structure to the sections of PVC pipe to form the base of the uneven bars. Sand the top tubes or wear them down with the wire brush to rough the edges so they will be able to hold chalk.