I have one of those big plastic cutting boards. It is a pain to wash, rinse and store this sized cutting board. I wanted something smaller for a quick onion or pepper chop so I decided to make one.
This is made from Maple scraps I had laying in the shop. I used yellow glue. (I highly recommend using a waterproof or outdoor type glue) and finished with a food safe wood finish.

Step 1: Cut and Mill Your Lumber

I cut 6 pieces about 1.25" wide 1" thick and about 10" long. My table saw is square enough and my blade was sharp enough to get these square, the first time around :)

All of these dimensions are based solely on what I had in the scrap pile and the size I had in mind, so go crazy if you want . Most all regular cutting boards are made in the same fashion.

Step 2: Glue the Boards and Clamp It Up

Wood has a tendency to warp with moisture and time working against it. When gluing a wood board to another along the edge, it is a good idea to flip the direction of the grain every other board. What that means is, when looking at the end-grain of each individual board look at the direction of the tree rings and mark with a "U" on the end. After you mark each board make every other "U" upside down before glueing and clamping.
After you have your boards lined up, it is time to break out the glue and clamps.
Glue the boards edge to edge and clamp it all up. Try to get all the boards as flat as possible with one-another. This will make things much easier later on...

Let it sit for at least 2-4 hours before you un-clamp the board.

Step 3: Flatten the Top and Bottom of the Chopping Block

I used a hand-plane on one side and a belt sander on the other. The only reason I used the hand-plane was to see if I still knew how to use it. I did, and it worked out excellent, but I must admit, my shoulder wears out pretty quick now-a-days... I sharpened the plane Iron at least ten times during the course of one side. I know I am using the wrong type of hand-plane for this, but it is what I had on hand.

The other side got the belt sander. Just flatten is as best you can. The most Important thing to remember if you are using the belt sander is to KEEP MOVING... If you stand still with it, it will go deep fast. Sorry, no pics of the belt sander process...

Step 4: Chop the Block Into Shape

I used my band saw, but my blade is way to large to cut any kind of curved shape. So, taking a lot of straight cuts got it done good enough.

After you have the shape cut out it is time to sand the edges, top and bottom. I used a power sander and 150 grit for the top and bottom. I used a stationary 12" disk sander, spindle sander and belt sander for the edges. If this were a square cutting board, it would not require near as much sanding.

Step 5: Raise the Grain

After using the 150 grit sandpaper on the edges to remove the tool marks, I sanded the whole thing with 220 grit.
Once this is completed, I removed all the dust with an air compressor.

The first time this board sees water, the wood grain swells up and tiny wood fibers pop up making the entire surface feel rough to the touch when it dries. So doing this on purpose in a controlled fashion makes for much smoother surface for a long time to come..
Simply whipe the entire surface down with a clean wet rag.
After it has dried, you will notice the rough surface. Have no fear, this part is easy. I used 320 grit over the entire chopping block and it felt as smooth as glass.

Sorry no, pics of this process, but it is pretty straight forward.

Step 6: Finish the Chopping Block

You can finish this however you like as long as you use a 100% food safe finish. See what I did there?
You dont have to make your own. luckily, you can buy cutting board conditioner from any home store.

Simply, wipe it down, let it sit for a while. Then wipe it off. This will need to be done a couple times a year with regular use. So, I do this step a bout 3 times before I say it is finished and ready for use...

After you are happy with the finish, you are ready to chop!

I added some stick-on cork dots to the bottom to give it some grip.

This thing is awesome for cheese too. :)

Thanks for looking.