Place one 26-inch section of a 2-by-4 on a flat surface, resting along the 2-inch edge. Line up the end of two 44-inch 2-by-4s to each end of the 26-inch 2-by-4. The structure will appear to be a U-shape when lying on the ground. Drive two 4-inch screws through the 26-inch 2-by-4 at each end to create a permanent hold.
Place an additional 26-inch 2-by-4 at the opposite ends of the 44-inch 2-by-4s. Drive two 4-inch screws through the ends of the 2-by-4 to bond the four sections of 2-by-4 permanently. This will enclose the U-shaped structure to create a rectangular frame measuring 48 inches long by 26 inches wide.
Repeat Steps 1 and 2 with the remaining two 27-inch 2-by-4s and the two remaining 44-inch 2-by-4s to create a second rectangular frame. One frame will be placed at the base of the 4-by-4 legs and the second piece will be placed along the top.
Place all four sections of 4-by-4s side-by-side on a flat surface running vertically. Measure up 8 inches from the base edge on all four sections and mark this location with a pencil. Turn the 4-by-4s over one side to the left and measure and mark 8 inches from the base along this edge as well.
Stand two 4-by-4s upright on the floor approximately 27 inches apart. Place the second set of 4-by-4s approximately 27 inches apart. The two sets of 4-by-4s should be positioned approximately 48 inches from each other. All four of the 8-inch marks should be placed along the top of the structure with the pencil markings facing outward.
Place one rectangular frame created in Steps 1 and 2 over the four 4-by-4s. Slide the rectangle down the 4-by-4s until it is resting flat on the floor with one 4-by-4 positioned inside each corner. Drive two 4-inch screws through each side of the 4-by-4 at each corner to join the frame to the 4-by-4s permanently.
Slide the remaining wood rectangle over the 4-by-4s until the top edge of the frame is lined up with the 8-inch mark on each 4-by-4. Drive two 4-inch screws through each side of each 4-by-4 to secure the frame to the 4-by-4s permanently.
Flip the structure over and place it on the bottom edges of the 4-by-4 legs. Place the 26 inch by 48 inch section of plywood over the structure, lining up the four sides of the plywood with the outer edges of the 2-by-4 frame. Drive one 4-inch screw every 12 inches along the perimeter of the plywood to secure the workbench top to the frame.