This Instructable covers building a standard set of cornhole boards. If you are interested in building a nesting set, my Instructable shows you how here: https://www.instructables.com/id/How-to-Make-Nestin...

If you want to get real fancy and make a rolling set, my Instructable here shows you how: https://www.instructables.com/id/How-to-Make-Rolling-Cornhole-Boards/

To make a set of boards, you will need the following:

Materials

3 96" 2x4's
1 96" 2x3
4 3 1/2" long 5/16 diameter carriage bolts
4 5/16 diameter nuts
4 5/16 diameter washers
16 2-1/2 inch coarse drywall screws
2 2'x4' pieces of half inch plywood (one sheet of plywood will yield four of these, they can be cut to size in the store where you buy them)
Primer
Paint
Water based polyurethane
Putty
Wood Glue
1-1/2" brads

Tools

Chop saw or circular saw
Drill
Hammer
Air compressor
Air powered brad nailer
5/16 drill bit
3/8 drill bit
3/32 drill bit
Countersink bit
6 inch hole saw
250 grit sandpaper/sanding block
putty knife
Paintbrushes
Pencil
Awl
Tape ruler

Step 1: Making the Sides

To start building the frame of your set of boards, lay two 2x4's on a flat, even surface. Take one of your pieces of plywood and lay it across the 2x4's. Slide the plywood so that it is even with the end and the side of one of the 2x4's as shown in the first picture. Mark the 2x4 with your pencil and cut the board on the mark. Cut a second 2x4 to the same length.

On one end of each piece, measure 4-1/2 inches from the end of the board and make a mark. Measure 1-3/4 inches from the edge of the board to the mark you just made, making a second mark. At the intersection of the marks, take your awl and make a small indentation in the wood. Next, using a drill or drill press and a 5/16 drill bit, drill through the indentation. These holes will be used to hold on the legs.

Step 2: Making the Ends

Next, place your plywood on a flat surface and lay your 2x4's down side by side on one side of the plywood as shown in the first picture. Take another pieces of 2x4 and lay it perpendicular to the side pieces. At the edge of the plywood, mark the 2x4 with your pencil. Cut the wood on this mark then cut another identical piece.

Step 3: Pre-drilling

Take the two side 2x4's. Using scrap wood, elevate them so that you can drill through them without hitting the ground. As shown in the first picture, the boards are laying with their 4 inch sides up. Using your 3/32 drill bit, drill two holes into the side boards 3/4 of an inch from the ends. Do this on both ends of the side boards.

Use your countersink bit on each of the eight pre-drilled holes so that the head of the screws will be below the surface of the wood.

Step 4: Making the Frame

Now all of the pieces are ready. Lay all of the pieces down in the shape of the frame. Put wood glue on the ends of the end boards. Make certain that the leg holes on the side boards are on the same end and that the sides of the boards with the countersunk holes are facing out.

To put the frame together, you may need an extra hand or two. This person will line up the end pieces with the side pieces and make sure they are flush while the other person uses the drywall screws to fasten the sides to the ends.

Step 5: Attaching the Deck

Place the plywood sheet on the frame to make certain it fits. If it does, take it off of the frame and line the top of the frame with wood glue, using a paint brush to even out the glue. Place the plywood sheet back on the frame and make certain it is centered. Press the sheet onto the frame to compress the glue. Use the brad nailer to fasten the plywood to the frame, leaving about 6 inches between each brad. Be careful to hold the nailer straight up and down so that no brads stick out of the side of the frame. If any of the brads are sticking out of the wood, tap them in with a hammer.

Step 6: Cutting the Hole

On the end of the board with the leg holes, make a mark 9 inches from the end of the board and centered between the sides. Make an indentation here with your awl. MAKE CERTAIN YOU'RE PUTTING THE HOLE ON THE CORRECT END!!! This will save you a lot of frustration later.

The next part can be sort of tricky if you don't have a hole saw. You will have to trace 6' diameter circle and carefully cut along it with a jigsaw. Here, a 6" hole saw makes this much less of a headache. Place the hole saw's bit in the indentation and cut through the board. You should use a powerful, low speed drill for this. A regular drill will not have enough power to turn the saw and will allow the saw to bite into the wood causing the drill to turn rather than the hole saw. It's an easy way to hurt yourself.

Dogs like to play with the circle scraps.

Step 7: Friends Don't Let Friends Skip Leg Day

To give your boards some angle, you need to make your legs. First, take your 5/16" carriage bolts and hammer them into the leg holes. Next, take a piece of 2x3 and drill a 3/8" hole in one end of it, centered on the 3" side of the board 1-3/4" down from the top. Using a chop saw or circular saw, make two 30º cuts on the top of the board. This will allow the leg to swivel without hitting the board.

The next step is a bit more tricky. Here, you will need a long, flat table or countertop. Attach the 2x3 board you just cut to the frame using the leg bolt. Put the cornhole board up on the counter, hanging the 2x3 board off of the side of the counter as shown in the 7th picture. An extra set of hands is helpful here. Making sure that the deck of the board is exactly 12" off of the counter, use the counter as a straightedge to mark a line on the leg. Cut along this line with your saw. Make another leg for the other side and you will be set.

Using this method allows you to size the legs perfectly for your boards so that the deck will be at the right height and so that the legs will have the maximum amount of surface area on the ground.

Step 8: Making It All Smooth

Using your favorite type of wood filler, go over every brad on the deck. Also fill in any blemishes on the sides. Cover up the screw holes and any gaps. Give the putty sufficient time to dry then sand it down. Make sure to sand the edges of the hole as well. You can use a power sander for the sides. I recommend hand sanding the deck so you don't run the risk of messing up the deck.

Step 9: Painting

After your boards have been sanded, put a nice coat of primer on them. Prime the inside of the boards as well for added protection. Don't forget to do the legs! Next, paint your base color onto the boards. It's a good idea to put multiple coats on to make sure there are no streaks.

After that dries, it's time for artwork. Here, you can do whatever you want! Personally, I use a projector and print designs onto it, then project the designs onto the boards and trace the projection with a pencil. After that, I just paint between the lines! The key to good artwork is patience. It takes time to make it look right.

After your artwork is finished, you should apply a few coats of water based polyurethane to protect the artwork. MAKE SURE IT IS WATER BASED! If it is solvent based, the clear coat will turn yellow in a few weeks and ruin your artwork. You don't necessarily need to use outdoor polyurethane here; all it adds is UV protection. Indoor polyurethane is often used on floors and provides excellent protection against scratches and scuffs.

Step 10: Have Fun!

After you make your second board, you're just about ready to play. Attach the legs to the boards using washers and 5/16 nuts. All you have to do now is make or buy some beanbags and have fun! Remember, the key to the whole process is patience. If you rush yourself, you will definitely make mistakes! I hope this Instructable helped you out. Comment if you have any questions at all! If you are interested in a set of boards, you can find my website on my profile.