Intro: Make a Tandem Axle Trailer Jack
If you've ever had a flat tire on a loaded trailer, you know it can be a challenge to jack it up and change the tire. This simple curved wedge "jack" or "chock" makes it very easy to change trailer tires and can be made in an hour from scrap wood. The design is based on the EZ Jack Wheel Chock. http://www.amazon.com/High-Country-Plastics-Wheel-Chock/dp/B000R5PMWE
Here's a video of how it works for a rear tire flat. If your front tire is flat, simply put the block behind the rear wheel and back-up. This block can also be used to chock a tire on any vehicle or trailer by turning it upside down and jamming it under a tire. Very handy.
Step 1: Make a Template of the Jack
The first thing to do is cut out a wooden template of the jack using the drawing below (pic 2). The squares in the drawing are 1" x 1". I created a grid of 1" squares on a piece of 1/4" plywood (pic 1) and cut it out on my bandsaw (pic 3). Alternatively you could make your template from cardboard, poster board, or even paper but I like to use wood so I can save them for future use.
Step 2: Cut the Wooden Pieces & Glue Them Together
The next step is to mark and cut the wood you are planning to use. I used some old wooden shelves that were 1x12s. The white contact paper made it easy to see my marks so I removed it after making my cuts. The jack needs to be around 5-6" wide so I used 7 pieces which is 5 1/4". You may choose to use 8 pieces or more depending on your trailer tire size. You could also use 2" wood or whatever you have. The commercially available aluminum chock is rated at 20,000lbs so I think this is only a question of tire weighth and stability. I'm not an engineer, but a 6"x6" solid wood chock should easily out perform the aluminum version in my opinion. The minimum board width is 7 1/2" for cutting out blanks and each piece is 24" long.
Since this isn't exactly fine woodworking, I simply cut the pieces on my bandsaw and glued them up. The sides aren't exactly smooth but it doesn't matter as long as it's somewhat close. You can be as precise as you want, but since the tire is rubber and the ground will probably be uneven, small differences are insignificant.
With all my pieces cut, the next step is gluing them together with regular wood glue. Apply a nice even amount of glue to the surface of all boards and clamp together. Follow the directions on the glue bottle to determine how long the stack should remain clamped together. I let mine sit overnight in the clamps (pic 2). Pictures 3 & 4 show the finished wooden jack.
Step 3: That's All.
That's all there is to it. The final chock weighs 11 pounds which is what the aluminum chock weighs also. The big difference is this chock helped me use up some old wood scraps instead of paying $70+ for the aluminum chock. I considered putting screws in the sides or through and through bolts, but in the end it seemed unnessary. Good wood glue is stronger than the wood itself so I'm not going to bother with bolts or screws. It won't hurt a thing if it makes you feel better to add some reinforcements. These jacks are so easy to make that I'm planning on making one for each of our trailers just so we have plenty of them around. Hope these work for you too! I look forward to your comments and suggestions for improvement.