disclaimer: check your local laws to make sure they are not illegal where you live before making them, don't hit anyone with these and use common sense. I am not responsible for anything stupid you do with them.

What you need :
Wooden dowel rod 3/4 inches thick ,14 inches long
Small chain
Drill & drill bit
2 crown bolts
Aviation snips (or something else that can cut chain)
Some type of saw

Step 1: Saw & Drill

First take your saw and cut the wooden dowel rod in half so you have two pieces that are about seven inches long. Then find a drill bit that is a little smaller then the crown bolts screw and drill a hole in the top center of each rod. Make the hole about 1 1/2 inches deep.

Step 2: Cutting the Chain

Use your aviation snips to cut the chain, it make take a couple of tries for the chain to cut.

Step 3: Securing the Chain

Take a crown bolt and screw one into each rod all the way up to its hook.
Put one end of the chain over one of the crown bolt's hook and squeeze it closed with pliers (for a better grip) Take the other end of the chain and do the same with the other crown bolt.

Step 4: Your Done!!

And your done! Now you can show off your new pair of wooden nunchucks to your friends ( not recommended because they will want to play with them and will probably end up knocking someone out...most likely you), play with (not recommended you will probably knock yourself out) or use as a decoration (recommended for obvious reasons )