After having our floors done, there were a whole bunch of short scraps that the flooring guys didn't use. It was nice hardwood (3/4" oak) so I couldn't let them throw it all away. It took a few months, but I found a great way to use up the various short lengths - with a rolling cart (two, actually). The great thing is that you can change the size of your cart to match the space that you have or to match the scraps that you have. I ended up making one cart for all my audio equipment, and then with a few modifications, I also made a rolling cart for the laundry room that holds all of our detergent and supplies.
Step 1: Figure Out Your Dimensions and Sort Your Scraps
First, you need to figure out the size that you want to make. Then sort through your scraps and make sure they will work for your dimensions. The nice thing about the flooring pieces that I was using was they had groves no only along the length, but also along the ends, so I could glue two really short pieces together if they weren't long enough. Although you probably don't want to do this for the vertical pieces as they will be holding the weight of whatever's on the top shelf, so make sure you have at least six pieces equal to or longer than your desired height.
Step 2: Glue Up Your Shelves
Once you've got your pieces sorted, it's time to glue up your shelves. Lay out the pieces and make sure that you will have the desired depth after all the tongues and groves are mated.
HELPFUL HINT: One of the things that I found after gluing up the first shelf was that the tongues and groves were terrible clamping surfaces, and the whole shelf wanted to curl up as I tightened the clamps. To make things easier on the second shelf, I took the front and back pieces of the shelf to the tablesaw and ripped off the tongue from the front piece and the grove from the back piece to give me a nice flat surface for the clamp to press against as I glued up the shelf. Make sure you account for this as well when laying out your pieces and calculating the depth of the shelf.
Once you're all set, apply a nice coating of wood glue to both sides of the tongue and inside the grove and then put them in the clamps. It's not shown in the picture, but make sure to put clamps on both sides of your shelf to help keep it flat as you tighten.
After the glue was dry, I sanded the top surface and then cut the sides to the final width with a panel cutting jig on the tablesaw.
Step 3: Cut Your Vertical Pieces and Your Bottom Stretchers to Length
You'll need 6 vertical pieces and optionally 2 stretchers for bottom.
You can cut these either on the miter saw or on the table saw.
SAFETY TIP: If you're cutting these on the tablesaw, you do not want to crosscut wood directly between the fence and the blade as you can have kickback. Clamp a piece of scrap wood to the front edge of your fence and then measure off of that. When you push past the blade and make your cut, there will now be a gap between your wood and the fence so that the wood won't get pinched between the blade and the fence if it twists slightly.
The length of the 6 vertical pieces should be whatever you'd like the height to be.
The 2 optional stretchers go front-to-back on the left and right edges of the lower shelf. The wheels screw to these and it just adds a little extra strength if you're going to be loading it up with some heavy stereo equipment like I was. You can see these in the fourth picture of the assembled cart in Step 5. You can also just screw the wheels directly to the bottom shelf if you wish and skip the stretchers.
Step 4: Add Rabbits to Your Vertical Pieces
You'll need rabbits at both ends of all your vertical pieces. I also did a rabbit along one edge of two of the vertical pieces so that I could make an L-shape at the rear of the cart.
For the rabbits at the top end of each vertical piece, you'll want the rabbit width to be equal to the thickness of your top shelf.
At the bottom of each vertical piece, the rabbit width will depend if you're using the bottom stretchers or not. If you are, the rabbit width will be equal to the thickness of your bottom shelf plus the thickness of the stretcher. If not, the rabbit width will be equal just to the thickness of the bottom shelf.
For the rabbit along the edge, the width will be equal to the thickness of the vertical piece that it's mating with. You can see a picture of the L-shape in the second picture of step 5.
Step 5: Assembly
Once you've got all your vertical pieces cut and rabbited and your shelves glued together and cut to final width and depth, it's time for assembly.
I started with the top shelf upside-down on my workbench. I then screwed the vertical pieces to the top shelf with #10 wood screws into countersunk holes. I then laid the bottom shelf it its rabbits and screwed it in place. I then added the bottom stretchers and some casters I picked up at Home Depot. The final touch was two small triangle pieces that I added to the two upper front corners to add a bit more stability and a nice decorative touch.
Step 6: A Quick Finish and Your Cart Is Ready to Go
I used a wipe-on polyurethane as my finish. Two coats with a light sanding in between and the cart was done.
With some modifications, I used almost the exact same approach to make a three-shelf cart for the laundry room. I made a dado in the middle of each vertical piece to receive the middle shelf, and I used up a few more pieces to add sides to the shelves. It slides in between our utility sink and the washer/dryer and the wife loves it.