Measure along the edge from one corner of the plywood out to six feet and make a mark. Place the framing square on that mark, and draw a perpendicular line up 18 inches.
Place the end of the chalk box on the corner of the plywood mentioned in Step 1. Pull the string out to the end of the 18-inch line and pop a line. This gives you the pitch of the ramp.
Cut this piece of the ramp out with the skill saw. This is one side of the ramp. Next, repeat Steps 1 and 2 to create the other side of the ramp.
Lay out a 2 by 4 flat and place the bottom leg of the plywood ramp side on it. Be certain that the 18-inch end of the ramp is flush with the end of the 2 by 4. Go to the angled end of the plywood and draw a line on the 2 by 4 indicating the angle of the cut so that it will match the slope of the plywood side. Cut the angle with the electric miter saw. This is the bottom of the ramp frame.
Cut another 2 by 4 at the same angle. Place the 2 by 4 from Step 4 flat on the ground. Lay the 2 by 4 from this Step on the end of the 2 by 4 from Step 4. This will be the top of the ramp frame. It will not be cut to length yet.
Place the plywood ramp side on the two 2 by 4’s. Be certain that the bottom and top pieces of the frame are flush with the edge of the plywood. On the 18-inch end of the plywood, mark the 2 by 4 to give you the length of the top piece of the frame.
Lay another 2 by 4 flat on the ground. If there is a piece of scrap left from the other cuts, you can use it. It will need to be at least 18-inches long. Place the plywood on the 2 by 4 so that it is flush with it on the 18-inch end. Draw a line on the 2 by 4 indicating the angle at the top of the frame. Cut the angle and then the length. It needs to fit between the top and the bottom of the frame.
Repeat Steps 2 through 7 twice more. This will give you three frames upon which to secure the plywood.
Drill pilot holes everywhere the frame joins. Secure the frame with 3-inch deck screws. Be certain that the screw heads are below the surface of the 2 by 4’s.
Cut 12 pieces of 2 by 4 to 15-inches in length. Secure these with3-inch deck screws between the fames to result in a frame that is 34 ½ -inches in width. Stagger them for maximum support. Next, secure the plywood ramp sides to the frame with the 1 ½-inch deck screws.
Cut a piece of plywood 36-inches wide. Leave the length at 8-feet for now.
Set the skillsaw at the angle on the electric miter saw. Cut the edge of the width of the plywood with the skillsaw. This will allow the plywood to sit next to the ground.
Secure the plywood to the frame using the 1 ½-inch deck screws on 8-inch centers. The plywood will hang off the end of the ramp.
Place the chalk line on one side of the plywood at the top of the ramp and the end of the frame. Pop a line across the plywood.
Be certain that the angle set on the skillsaw is the angle needed to cut the plywood flush with the end of the frame. Cut the plywood to length.