You have a couple options when building a wooden mailbox. You can either build the entire thing out of wood or you can use a standard sheet metal box as the base and cover it with wooden ribs. If you’re on a budget or don’t have a lot of time to spend, I recommend the wooden ribbed box. However, if you want something that looks a little nicer, definitely make the entire box out of ribs.
Build and design plans
Start by cutting two 9” x 9” pieces and placing them on top of each other. Use a compass to create the arch that you want. While the pieces are on top of each other, use a band saw to cut out your arch.
Take one of the ends and make an even ¾” from the bottom left all the way around to the bottom right. This is going to be the door.
Next we’re going to make the bottom of the box. This can be done with less expensive wood as it doesn’t show. Typically a mailbox is 19” long, so that’s the dimensions we’ll be using. Cut a notch in the bottom of the door so that your door flap can mount in there flush.
Attach the front and back to the bottom using glue and nails. Next, attach the door to the bottom of the mailbox using a hinge. You’re going to want a stopper so your door can’t be pushed further back into the box. Glue a small piece of wood to the top of the door that prevents it from being pushed in too far.
Cut the sides of the box so the height is equal to the bottom of your arch. Your mailbox should now be taking shape, there are only a few more steps.
Cut a series of 19” 1” ribs to make the roof of the mailbox. You can make them slightly smaller but no bigger because you need to preserve the arch shape. Glue and nail each piece so it fits snugly to the piece next to it.
Take a hand planer and shape it maintain the round curve. Get off as many of the sharp edges as possible. Next, take the orbital sander and give it the finishing touches.
Lastly, create the flag. Make it any shape you want and cut it on the band saw. Screw it to the mailbox along with a simple pull knob on the door.