These are 2 of the side tables that I have made using pallets. Except for the wood glue, the nails, and the linseed oil to finish the wood, everything is repurposed!
Step 1: The Pallet . . . .
You will need more than one pallet - one that you slice in half and one that you use the 2x4's to make slats out of. Though the whole pallet is bulky, I cut it in half using my table saw. Then, I set the guide to between 1/8th and 1/4th of an inch to cut the slats. 1/8th works great for slats that are decorative only; 1/4th inch slat will definitely bear some weight, but I find them a bit too thick.
Step 2: The Pieces . . . .
Either cut the 2x4(s) to the width you need for the table, or, after you've cut the slats, cut the slats to the width you need. Once you have all the pallets and slats cut, you are ready to start assembly!
Step 3: The Top of the Table
Using 2 slats that will run the length of the pallet sides. I have found (not pictured) that it is best to inset the long slats the width of the 2x4s that are part of the pallet. When putting the slats across, use a slat on edge for the perfect gap width, much like tile spacers. Attach with wood glue and a pinner, or hold off on the pinner (less clean-up) until the next step. Also, to figure out the width of the top, on long, full size pallet sides, I make the width the height of the pallet cut in half. For the smaller tables (pictured at the end), I make the width of the table the width of the pallet piece, for a square table.
Step 4: Attaching Top to Pallet Sides
This was my first pallet side table, so I thought I needed structural support. Hence, the added cross slats attached to the lower piece of the pallet. I have since stopped doing that, but my cats love these as 'dividers' when they want to play and swat at each other.
Place the slat top on the top of the pallet sides, with the long support slats on the underside, Use wood glue and the pinner to attach.
Finally, use the long slats to go atop the slat top to the edge, as shown in the 3rd picture. Again, use wood glue and the pinner to attach. Once it is secured and the glue has dried, use either screws or nails to more securely attach the top to the sides.
Step 5: Stability & Looks
Along the ends, attach boards that match as close as possible those of the original pallet. I usually try to match the nail pattern found on the pallet. These boards make the table stable, and also give it a more finished look.
Step 6: Viola!
Finish the wood to your preference. I use linseed oil. Remember to coat the underside as well - all of the wood needs to be sealed.
These are pictures of the finished side table, and others that I have made. The smaller ones have the additional cuts to the pallet of that 3rd/end 2x4. The different shaded wood is from an old wood fence that I salvaged - I love the striking color difference.