2x4s (2-inch-by-4-inch lumber) are the building blocks of most wood structures and are used to support roofs and walls. They provide framework for insulation as well as electrical wiring. Other 2x4 wood projects include furniture, home remodeling and toys.
Use pressure-treated 2x4s to build outdoor furniture. Pressure-treated wood lasts longer outdoors and is bug-resistant. Build a stool by forming a frame the width and length you want the stool to be. Install 2x4s across the frame and fasten at the ends with bolts. For legs, form two X-shapes fastened in the middle with bolts. Saw the ends of each X flat and bolt the frame to the legs. To form the back legs of a chair, saw a 10-degree angle at one end of two 2x4s so that the back of the seat will sit at a slight angle, making it more comfortable. Make these two 2x4s taller than the front legs in order to attach a back across them. Form a frame and attach 2x4s across the frame to make a seat. Attach 2x4s in two of the corners underneath the frame using bolts. Attach the frame (which now includes the front legs) to the back legs using bolts.
Build a table by installing four 2x4s 2 inches from the edges in each corner of a sheet of ½-inch plywood, forming the legs of the table. Attach the 2x4s with wood glue and wood screws. To from bracing, attach 2x4s between the legs directly under the corner edges of the table.
Use a table saw to cut 2x4s in half lengthwise, essentially forming 1-inch-by-4 inch boards. Bevel one long end with a router and use the boards for baseboards or molding around a door. Glue two 2x4s together, forming a decorative 4-inch-by-4-inch beam and hang the beam from the ceiling. Fill the cracks with wood putty and stain or paint with a vivid color to match the surrounding room.
Draw train cars on a 2x4 and cut the shapes out with a router. Drill holes in the ends of each car for dowel pins. Insert the cars into the ends of the dowel pins, forming a train. Sand smooth and paint bright colors. Cut different shapes with a router or a table saw to make blocks. Sand smooth and paint numbers or letters on the blocks. Make a simple doll bed by using 2x4s as slats for the bed. Attach 3/8-inch pieces of plywood to the ends of the 2x4s for the head and foot of the bed. For the legs of the bed, position the 2x4s 1 inch up from the edge of the plywood. Use wood glue and wood screws to attach the plywood.