All right, folks, I'm gonna get JIGGY with it. No, I'm not going to dance and leap around until the end if this turns out successfully.
A JIG is "a device that holds a piece of work and guides the tools operating on it."
This is going to be a BOX JOINT aka FINGER JOINT jig.
Step 1: SCRAPS FROM THE LUMBER CART
My lumber cart is looking a bit anemic, but this box joint jig shouldn't require a lot of material to make.
Step 2: THE ROUTER TABLE
I removed the fence from the router table.
Step 3: THE RUNNER
I found a piece of 1/4" wood from which I ripped a strip to act as a runner in the track already in the table. By adding a few pennies the strip was raised a hair above the surface of the table.
There should be absolutely no side to side movement or wiggle in this strip. It should fit snuggly. No wibble, no wobble.
Step 4: IT'S ALL ABOUT THE BASE
It's all about the base, no wobble. Sorry, just got an ear worm. Anyway. I glued the base to the runner, making sure the base was square with the table.
Step 5: THE FRONT FENCE
I found a chunk of colonial casing and trimmed the mitered ends for aesthetics. I glued and screwed it to the front of the base.
TIP: If your clamps ever lose one of the rubber cushions just use one of those thingies you put on the bottom of a chair to protect the floor. The glue is not the best and it is advisable to add a little daub of super glue to it.
Step 6: THE BACK FENCE
I found a chunk of 2 x 4 and used it as the back fence and ran the router blade up to it. I screwed the fences through the base and counter sunk the screws. Make sure this fence is square to the base. I've seen some people secure right angle wedges to the back of the fence to keep it square.
Step 7: THE KEY TO THE WHOLE JIG IS THE KEYS
The keys are strips the EXACT WIDTH of the bit you are using. It took me a bit of finessing, but eventually I got a perfect fit. I cut two pieces. One is secured to the base and is one router bit width away from the cut made by the bit. The other is used to basically eliminate any space and will allow the router bit to cut a hole in the end of a board.
I raised the router bit a skosh above the thickness of the wood I'd be using. It is easier to sand off a protrusion than to fill in a depression. Then ran it into the rear fence and tested the keys.
IMPORTANT: The key height should be less than the thickness of the wood you'll be box jointing. I made that error and knocked out the key and trimmed it down and the spacer down to the proper height.
Step 8: BOXING DAY
Now to test the jig. I cut two pieces of wood the same size. The first I held up to the permanent key, turned on the router, slid the fence and cut a notch (A TONGUE). The second I added the spacer and cut a notch in the very end of the board (A GROVE). Then I removed the spacer and staggered and aligned the two notches on and up to the fixed key. It then became a matter of leap-frogging over the key until I reached the end of the board.
The same result can be gotten by doing each separately. The first goes against the permanent key, the second goes against the spacer. Basically, you are creating tongues and groves that will go together to form a joint.
Step 9: THE JIG IS UP
I was very pleased with the result. Now I must admit I looked at dozens of How Tos on making this jig and Frankensteined my own version to fit my router. You'll notice I only have one runner where as most I saw have two. Even one I saw made a second runner off the side of the table. Some were so elaborate it'd take me forever to build it. The simple one I show here took a few hours on and off while doing other things around the house. It meets my needs, and that is the whole purpose. Make a jig to suit your personal requirements.
NOW...drum roll, please.....
Step 10: GETTING JIGGY WITH IT!
Let's get Jiggy With It!