Measure the length of the space where you intend to install your bar. Use the measuring tape to determine the width of your bar as well. It is best to build using a standard bar height of 42 inches.
Cut four pieces of 2-by-4-inch hardwood to the length of the bar using a circular saw. Subtract 4 inches from the width of the bar to account for the thickness of the first boards you cut, and cut four pieces of 2-by-4-inch hardwood to this length. You will use these boards to construct the basic frame for your bar.
Arrange the eight boards you just cut into two rectangular frames using two of the longer and two of the shorter boards for each frame. Stand the boards upright on their longest narrow edges and sandwich the shorter boards between the ends of the longer boards. Drive 3-inch wood screws through the longer boards into the shorter ones to secure the frames.
Cut two additional pieces of 2-by-4-inch hardwood to the width of the bar, minus 4 inches, for cross braces. Measure to find the center of the two rectangular frames you just constructed and slide one piece of 2-by-4-inch hardwood into the center of each frame so it is parallel to the other width pieces. Drive 3-inch wood screws through the longer boards into these cross braces to secure them.
Cut six pieces of 2-by-2-inch hardwood to the height of your bar using the circular saw. If you know how thick your bar top is going to be, subtract the thickness from the total height of the bar to determine the proper length for your 2-by-2-inch hardwood boards.
Lay one of the rectangular frames flat on the floor. Stand one of the 2-by-2-inch hardwood boards you just cut upright on top of each of the four corners of the frame. The bottom of the upright boards should be flush with the top of the frame and the outside edges should be aligned with the corners.
Drive 3-inch wood screws at a downward angle through the upright boards into the rectangular frame to attach them. Stand the remaining two pieces of 2-by-2-inch hardwood upright on top of the center of the frame, aligned with the cross brace you installed earlier. Secure the upright boards in place using the same procedure.
Set the second rectangular frame down on the floor. Flip the frame with the vertical supports attached upside down and place it on top of the frame on the floor. Adjust the two frames so the vertical supports are aligned with the lower frame in the same way as the upper frame.
Drive 3-inch wood screws downward through all six vertical supports into the lower rectangular frame. When finished, you will have completed the basic frame for your home bar.