If you ever need to change your oil, replace an exhaust sensor or simply look at something under your car, you will need access to the underside. In order to get under the car you need an expensive lift or an easily-assembled drive-up ramp.
Measure 3 feet from the end of each 2-inch-by-12-inch-by-12-foot board and place a mark across the 2 inch edge.
Trace a line diagonally from the 2-inch edge mark of the board to the nearest corner, three feet away. You will have marked off a roughly 3-feet-by-12-inch-by-3-feet triangle-shaped piece. Repeat for the other 29 boards.
Using the saw, cut the boards along the marked lines.
Place 15 of the cut 2-inch-by-12-inch-by-12-foot boards on their 2-inch edge so that all the pointed ends are facing the same way. Ensure that the longer 2-inch side is on the bottom.
Ensuring that all the boards lined up side by side on the 2-inch edge, drill a hole through all 15 of the boards at once.
Insert the 23-inch-by-one-half inch threaded rod in the hole, install one washer and nut per side. Tighten finger tight. This will pull all 15 boards together and keep them in place to allow you to easily assemble the rest of the ramp. At this point you will have a loosely assembled 12-foot-by-22-inch-by-12-inch ramp.
Drill another 11 holes at 12-inch increments lengthwise along the ramp, installing the threaded rod, nuts and washers after each hole is drilled.
Place a half-inch wrench on one side of each threaded rod nut and hold. Place a half-inch socket on the other nut and tighten.
Cut a 22-inch piece of two-by-four. Attach by screwing the deck screws down into the top of the ramp at the square end to act as a tire stop.
Repeat steps 1-8 to create the matching ramp for the other side of the car.
Use treated lumber to ensure your ramp lasts a long time. Every car wheel base is different. Do not attach the left and right sides together, so that you can use your ramps for different vehicles. For added traction, paint the ramps with sanded grip paint. When ordering the lumber, it will be listed at the lumberyard as "2x12x12" and "2x4x6."
Use your ramps on a level surface. Ensure the vehicle is on the centre of the ramps with parking brake engaged. Be sure to tell someone that you are working under the car in case something happens. Before each use, verify the tightness of through-bolts to account for variations in wood moisture and swelling and shrinkage.