Building a composter is an easy, affordable way to provide nutrient-dense humus for your garden soil and reduce the amount of trash you send to landfills. A typical rotary compost tumbler operates by elevating a cylindrical drum on a frame and mounting it on an axle. Mounting your tumbler allows you to spin it, which mixes the compost and helps introduce more oxygen for the decomposing bacteria in the organic materials. According to Fern Marshall Bradley, author of "Gardener to Gardener," you can produce compost within approximately two to three weeks if you turn your tumbler four to six complete rotations each day.
Search for a container for your compost tumbler. Look for a 55-gallon plastic drum approximately 36 inches long. Make sure that it has never contained chemicals in the past that may have infiltrated the plastic material and could leech into your compost.
Drill a single hole in the center of the top of your plastic drum, using a 5/8-inch drill bit. Drill a similar hole in the center of the bottom of the plastic container.
Turn the drum on its side and use a tape measure to find the center of the side. Mark a door opening at least 12 inches by 16 inches. Use a jigsaw with a general-purpose blade to cut the rectangular opening out of the center of the drum's side. Reattach the plastic piece that you cut from the side of the drum, using two small hinges on one side; secure the hinged door by attaching a hasp lock to it.
Lay two of the 40-inch-long 2-by-4-inch boards parallel to each other on the ground. Position one of the 30-inch-long 2-by-4-inch boards perpendicular to the 40-inch boards, leaving the ends flush with the outside edges of the 40-inch boards; locate it about 15 inches from the bottom of the 40-inch boards. Screw the ends of the 30-inch board to the two 40-inch boards with wood screws.
Lay a second 30-inch board parallel to the first 30-inch board, positioning it at the tops of the 40-inch boards. Screw it into place. Cut a 1-inch-square notch out of the top edge of this 30-inch board with a jigsaw. Repeat this construction process for the second set of 40-inch and 30-inch boards.
Pair the 1-by-4-inch boards into two X shapes. Secure the two vertical supports to each other by screwing one set of crossed 1-by-4-inch boards to each side of the supports. Cut the ends of the 1-by-4-inch boards diagonally to match the vertical lines of the supporting 2-by-4-inch boards.
Fit the steel pole through the two holes you made in the ends of the drum. Lift the drum and mount it on the framework by resting the ends of the steel pole in the notches you made on the top supporting boards.