Draw the blueprints for your firewood processor design. Use basic models as your guidelines. Commercial plans are available as well (see Resources).
Purchase a log splitter and a log cutter. A log splitter should be hydraulic or electric and be able to split a log into four or eight pieces.
Place the channel iron on the ground in the place where the chassis and axles will be. Attach the wheels and the axles to the channel iron. Use a level to make sure that the axles are aligned properly. Lay the channel iron pieces in a rectangle and weld them together to create the frame. Place the frame on top of the chassis.
Construct the vertical guards for the splitting and cutting areas out of the steel mesh. The steel mesh should provide a protective area around both the places where the wood is being cut. Bolt the saw to a frame that is welded and has a pivot attachment allowing the saw to be raised and lowered. Weld steel stops to the 22-inch depth of the firewood. Either buy or construct a hydraulic mechanism (see Resources) to push the log to the splitter plate. Weld flat steel sections to brace the construction.
Run different sized wooden logs through the processor to test it.