How to Make a Half Lap Joint on a Table Saw with Two Cuts and a Jig

Let's do a half lap joint here on the table saw. And do it by passing our material vertically over the blade and then horizontally. So with two cuts, we end up with this notch taken out. We're gonna do it using a shop-made tenoning slash half lap jig. So this will very securely hold the material upright like this so we can make the cut.

Need to do a couple things. Whatever your real project pieces are, you need to make sure you have test pieces exactly the same thickness. Cause our setup will be thickness specific. Now what I wanna do to get started here is first unplugged the saw that's already taken care of. Next, set the height of the blade to the width of my pieces.

So the easiest way to do that is put the material next to the blade. And then raise the blade until at top dead center here someplace. The top of the tooth is even with a top of the material. Now there's nothing wrong with slightly over cutting. And I'll show you that in just a little bit when we're done, why that's an advantage.

You definitely don't wanna undercut. So if anything, I'd rather have the blade a little bit too high than a little bit too low. Now to locate the fence, we wanna be cutting immediately to my left of a center line of this material. So what I'm gonna do is mark engage. Brup.

Don't move the pencil and finger, brup. So the center of this board is somewhere right about there. I'm gonna take advantage of that by putting my material into my jig and then I'm gonna align the saw blade so that it's to my left of that pencil. And I'm not gonna try to cut this perfect on the first run cause I probably won't get it perfect. And if I make it too small if I already take too much material off, there's no way for me to put wood back on.

So I'd rather leave it just a little too fat, do a test cut and then we'll come back and check and see what we've got. We're good to go there and there. Get the saw plugged in and we can make cut number one of our test cut. When we're done with set up and we move on to the next step. What we're gonna do is do a cut like this on the table saw and a cut like this, but I don't wanna change this setup.

So in order to get the waste out of here now I'm gonna use a hand saw. Then our test is to just simply put these together and see if we're flush across the face. And in this case we're not, and this is what I want. This means I didn't take enough material off. So I'm still high.

Whatever this step is, we moved the fence by half that amount. So I'm looking at a strong 1/16 of an inch. So I'm gonna move the fence closer to the blade by about a 1/32. Then we'll do another test cut. Closer, but not there yet.

All right, this is where we wanna be. We wanna end up where the faces are flush. Then we're ready to move on to our real pieces. Let's grab these and we just do the same thing all over again to each end of the piece. Now, one of the things to be aware of is that we're gonna make a cut, rotate and make another cut.

You wanna make sure that you don't spin the piece. So in order to help prevent that I'm gonna put an X on my pieces. And that X is always gonna be against the jig. Done with the jig. Now let me unplug the saw, and then we'll come back and do the next setup.

All right, here's what we need. You have to set the height of the blade so that we can take Waste out. So I'm gonna set the top of the blade at top dead center of its rotation, to where it's just under the bottom of this cut right here, just below that. Then the next thing where we're going with this is gonna use a miter gauge and we're gonna cross cut the pieces like this. However, if we use the fence to control the length that small offcut gets caught in here, and once it's trapped in there, very likely it's gonna get kicked back at you.

So we don't wanna use only the fence. We wanna use a stop block on the fence. So the way to make this setup happen is bring up the stop block and put the material against it. And then set the fence position so that the edge of the material is even with, or a little bit short of the edge of the blade. So remember earlier I said, it's okay if we cut these.

So they're a little too deep, not okay if we caught them too shallow. So right now the blade is just what I'd call a fingernail catch beyond this edge of the material. Great position for it to be in. Now we bring this back. So the result with a stop block is that we can contact the block, then move forward.

We're no longer in contact with the fence so that offcuts not gonna come zinging back at me. Let's try our scrap pieces first and make sure we got what we think we got. And then we'll go from there. There's our half lap joint. Nice and flush across the face.

Now, when I've talked about I'd rather over cut them than undercut them. Here's the result. The end grain of this piece is slightly past the long grain of this piece. So I glue these together and then you could use a block plane or a sander and take this end grain down until it's flush. Same condition is over here in this direction.

If it's the opposite, if the end grain ends up short, I'd have to take all of this material down in order to make it look flush. So at the end, grain is just a little bit proud of the long grain, very easy fix. So half lap joints, easy to cut on the table saw with the help of that shop-made jig or any tenoning jig, two-step operation. Make sure you use the stop block for safety. Great joint to have in your arsenal.