The use of a firewood cutting rack helps to prevent damagie to the teeth of a saw blade, whether a chainsaw or or standard hand powered saw. The idea of a cutting rack is simply to hold a log or a section of a log off the ground, thus keeping the saw's blade out of the dirt and rocks. Accomplishing this protects the teeth of the saw, leading to longer work periods between sharpening breaks. This leads to increased productivity when you're cutting firewood.
Use your tape measure to measure four lengths of 2-by-4 dimensional lumber 6 feet long. Mark your measurements on each board with your carpenter's pencil or a Sharpie pen marker. Measure an additional two pieces of 2-by-4 dimensional lumber to a length of 8 feet long. Mark these measurements as well.
Use your circular saw to cut the measured boards to length. Set the 8-foot sections aside. Always wear appropriate protective equipment including safety glasses and ear protection. Use the blade guard on your saw according to the manufacturer's instructions.
Take two sections of 6-foot 2-by-4 and place them together in an X-shape, with the flat sides of the boards touching in the middle. Use three 16-penny nails to connect these two together.
Repeat Step 3 with the other two 6-foot pieces of 2-by-4.
Set both X-frames on the ground, approximately 6 feet apart. Bring the 8-foot pieces back into the work area.
Attach the 8-foot boards to the bottom legs of the X-frame. Place one of the 8-foot boards on one side and the other on the other side. Use these 8-foot pieces to connect the two X-frames together. This provides lateral stability between the two frames. Attach the 8-foot cross braces with a minimum of three 16-penny nails on each end.