by If you are in the need to make repeatable dado joints, half lap joints or even rabbet joints, then this is the tool for you! With about an hour of your time and a very small list of supplies you will have this tool ready to go for your next project.
How it works.
A kerf make or also sometimes called a dado maker, works by having an adjustment screw that takes into account the thickness of the blade while measuring the thickness of a piece of wood that will be inserted into a dado. Once this adjustment screw is set just right for your saw blade, it will make the right size dado over and over again. No need to do any measuring or test fits with more cuts to get it right.
List Of Materials
- Hardwood of your choice
- (1) One inch by 1/4-20 bolt
- (1) 1/4″ washer
- (1) 1/4-20 wingnut
- (1) Small 3/4″ to 1″ long wood screw
- (1) 6″ length of T-Track
Lets Build It.
The process of building this little tool is a very easy process. And with the use of my free plans that are available, it’s even easier.
We’ll start by cutting a block of wood to width and height. The thickness should be right around one inch. And for the type of wood, I would use any hardwood you have available like Oak, etc. For me, I had some Walnut laying around so I used that.
Using the table saw, this will be a quick process. In my video the length was already cut so I only had to cut it to width.
Now that the block of wood is cut to size, we need to remove some material. This first area will be where we will be inserting the piece of wood to be measured that will then go into the dado cut.
First, by marking out the cut lines and then setting the blade to the correct height, we can finally start making cuts. With the use of a flat top grind blade, I started making repeated passes until all the area needed was removed.
Also note that I’m using a cross cut sled on my table saw with hold down clamps to make this process mush safer. If you are in need of any of these, I have build videos here – Cross cut build video and Hold down clamp build video.
The second area to be removed is for the T-Track “slider”. This process was just a bit more trickier due to not wanting to make the cut all the way through the length of the wood. To solve this little issue, I simply put a pencil line on my table saw surface to tell me when to stop pushing the sled.
Now we just line up our first cut and make a pass, move the piece over the width of the blade and cut again. And repeat till the width will allow the T-Track to fit just right.
Lets Drill Some Holes.
Now it’s time we drill two holes. One is for the bolt to hold the T-Track and the other is for the adjustment screw. Marking out the location for the bolt, I used a 3/8″ drill bit in my drill press to drill through the wood. A power drill will work just fine here as well.
Then while we’re at it, we’ll drill out the pilot hole for the adjustment screw using a drill bit size of just smaller than whatever size wood screw that you will be using for the adjustment screw.
Lets Put It Together.
Well we’re almost going to put it together. There’s going to be one more cut to do. But first we first need to put the T-Track in it’s slot. This is done by first sliding a 1/4″-20 x 1″ bolts head into the T-Track. Then slide the bolt through the hole in the wood followed by a washer and wing nut. Slide the T-track all the way inward and tighten the wing nut.
Now we can cut off the excess T-Track. It’s very important to make sure the T-Track is tight to the inward side. Otherwise this tool will not work properly.
And since the T-Track is a non ferrous metal, there is no issue using a table saw to cut this metal. When you make the cut to flush up the wood and T-Track be sure to raise your blade up unlike me. Oops, I had to make two passes.
Now We Can Finish.
Now that the end is cut flush we can install the adjustment screw. Just a simple process of screwing it in most of the way. Just keep in mind that the head of the screw will be sticking out the thickness of your saw blade once adjusted right.
Set It Up To Your Blade.
To set this tool up, we will first have to set the adjustment screw to the thickness of your saw blade. This is done simply by first resting the side with the screw up against the saw blade. Then with a screw driver screw in or out till the screw is flush with the other side of the blade.
Don’t worry if it’s not 100 percent perfect as we will be doing some test cuts followed by adjusting the screw some more.
To get it just right, we will do our first test cut. Start by inserting a scrap piece of wood that will act as the piece going into a dado into the tool followed by sliding the T-Track tight to the test piece. Once the T-Track is tight to the wood, tighten down the wing nut and remove the test wood piece.
Now lay either this same test piece or another one flat on the sled ready to be cut.
Since this is just a test cut, the location of the cut doesn’t matter. Now we’ll first set the dado maker in between the test piece of wood and the stop block. The dado maker will be up on edge so the T-Track is touching the stop block on one side with just the flat end of the dado maker touching the test piece on the other side.
Note my picture shows a test piece that’s already been cut.
This is now the time that you would make the first cut through the wood. After of course setting the cut height to what ever you want it to be.
Now for the second cut. Lay the dado make flat with the screw touching the stop block. This will allow the test piece of wood to slide closer to the stop block. Now we make the second cut through the wood.
Now just finish cutting whats left in the middle of the first two cuts with repeated passes.
Now that all the dado is cut out, try sliding in the wood to fit into this dado. My first test fit was a bit too tight so I unscrewed the screw just a smidge and repeated the whole process again. For me, I actually ended up too loose on the second try. So I had to go a third time by tightening the screw again an even smaller amount. This last time was just right.
Once you get the adjustment screw set just right, you can make all the dados you need over and over again. All with the perfect fit. I have now used this little tool on several other projects and I have to say I’m really happy with it!
