How to Make a Half-Lap Joint for Woodworking

Learn how to make half-lap joints from Makeville Studio in this Howcast woodworking video.

Half lap joints are a simple joint, in that you’re only removing half of the material from each piece and then just overlap with each other, but it’s also a very strong joint. It helps in a lot of different wood working type of projects, form anything like frames, to small tables.

Marking, measuring, and laying this out is very simple when you’re basically just having to capture what half the width of each piece of wood is. Where they overlap, mark those out and then remove the material.

We’re going to be using a dado set, built up thick blade in this saw. We’ve built up a thickness of about three quarters of an inch in there. We have a lot of material to chuck out of our pieces, so we are going to have to take successful passes over this blade in order to remove this wide piece of material.

So, first step in removing these, is set up a stop block to help us start and stop on the same place or each of these pieces, then what we’re going to be doing is starting on the shoulder line here of the half lap. So, I’m going to line up my line with that shoulder line, set up a stop block to capture the position of this piece of wood so that I could do this two times or 200 times and it will always be exactly the same.

Of course, the first thing we have to do is set the blade height correctly. So let’s do that. So, we can use a pencil line that we’ve marked, to mark out this joint as our guide, and I’ll just lower the blade down to right about at that line. A little bit below, just to be save. Okay, we’ve got the height set up, now let’s set up the stop block.

A stop block is a piece of wood that sits on the rib fence, and it’s going to sit back here, behind where we are making the cut, so that we’re not jamming the wood up between the fence and the blade when we make the cut. So, it’ll be back here and we will leave it behind. In order to set it up, we do need to bring it up here, so we can line up the blade.

All I’m doing is I’m lining up my pencil mark with the outside edge of the saw blade, so the blade is completely inside the part I’m cutting. Okay now with that in place, I’m just going to run the fence over a little bit. We’ve got the position for the stop block locked in, I locked the fence, and now I can bring the stop block back here. It’s a safe place to put it, and lock it in place. There we go, alright. That’s set. Now, we’re ready to go. Okay, now with the material removed from both sides, we can test our fit, and then glue it up, and you’re done.