VIDEO: How to Make a Lap Joint
JONNY HUGHES: How's it going? Okay, so we built this mast and we have these two pieces fit together so it looks like it's one thickness. What that means is we took out half of each piece to get them to fit together. This is called wood joinery. It gives your woodwork a cleaner outward appearance as you use fewer visible nails and screws to attach pieces. And we do that by taking a one and three quarter inch depth on your Skilsaw and you do a slice, do a slice three and a half inches to fit and taking out the width of the four by fours. Halving both wood pieces and fitting them into one another creates a type of wood joint called a lap joint. Once I make my two cuts, I can chisel it out and then you notch that out and you knock it out with your chisel in your hammer and it should pop out.
In this case it was a little wet so it was a little challenging to get it to just remove itself nicely. Whereas dry wood will just pop off and if it has a hard time I can do more cuts in between my two initial cuts and then use my chisel and tap it out. And if the waste is removed and the two pieces fit together so it looks like it's one thickness, it doesn't look like it's attached to it. It looks like it fits together. Arranging your lap joint so that your two pieces intersect perpendicular to one another creates a "cross halving joint." Hammer your joint together indirectly so the force won't warp or bend the wood. When you come together, you get a lot more strength than it being put on top of it, and it could actually turn. So this way, when it fits in together, it locks it in there. But yeah, that's the trick and it looks really nice too.