Easy Box Joint Jig How To Make Box Joints

Hey, you want to learn how to make a jig so you can make perfect box joints on the table saw every time? Well, watch this video. I'm going to totally show you how to do it. So you're going to want to start by walking over to your scrap plywood pile and picking out a few choice pieces. We're basically going to build a box with five inch sides and then a base that's approximately three feet by 18 inches wide. So once you cut down your side pieces, you want to get your base piece. Now for my base piece, I'm using pre-finished on one side so it's nice and smooth on the bottom. That'll help it run on the top of the table saw a little easier. Now it's important to note as we put our box together that we have to do it in a very specific order to make our jig work. So the first thing we're going to do is actually mark out the very center of our base piece. It's also important that you leave the front piece of our box about an inch longer than it needs to be. You want to be able to slide it to the left and I'll show you exactly why here in just a little bit. With our box pieces roughly cut, next we want to cut some pieces of wood that are going to glide inside the miter grooves on the top of the table saw. I have this little setup block that fits in those miter grooves perfectly so I used it as a reference to cut my rough pieces. Now I'm cutting these guide pieces out of hard maple because I want them to last a while so that I can use this jig over and over again. Once your wood guide pieces are cut to the proper width to fit inside your miter slots, next you want to cut them to the proper height. Now the exact height you're looking for is to be just proud of your table saw surface. I'm talking like maybe a 32nd of an inch. You just want to barely above the top of your table saw. So again I used a few little setup blocks to get my height perfect and set my blade accordingly. Then making sure your fingers are plenty out of the way, you run those back through the table saw, this time cutting the height not taking any off that width that you already cut. That'd just be silly. As you can see, they fit very nicely and are just proud of the table saw surface, just like we planned. With them cut to the proper width and height, it is time to cut them to length. The way that I do this is I insert them into the miter slot, push them all the way forward, and then find the center of my blade. You want your sled to be able to go past the center of your blade, so just move the mark forward a few inches and cut them to that length. At this point you should have two guides that slide nicely into the miter gauges on the top of your saw. Next you want to pull those guides all the way forward and line them up with the very front of your saw surface. Next we're going to attach the base of our sled to these guide pieces. So you want to lower your saw blade all the way into the table cabinet, and then I like to run some pieces of blue tape next to each one of those guides. We're going to glue them to the bottom of our sled, and if there's any squeeze out, this just makes it a once it's all glued up. To glue the sled base to these guides, we're going to be using a super glue with an accelerator spray. So in order to know where to put the accelerator and where to put the glue, it's a good idea to put your sled base on the saw and mark out exactly where those guides are going to land on that sled base. Before you lift up the sled, however, you want to move your fence over and put it right in position. This will help you make sure that you can get that square and back in the proper position before you glue it up. Next you want to transfer those marks you made onto the bottom of the sled so that you can find out exactly where you need to put your accelerator spray. You can use any super glue and accelerator spray. For this we're using Starbond simply because they sent me a big box of it, so might as well use what we've got. You want to apply the super glue onto your guide pieces and the accelerator onto your sled base. Just make sure you don't drip any of the glue off as you're trying to get your base in the proper placement. As you're putting your base on, you want to start by pushing it firm against your table saw fence and bringing it flush with the front of your saw. This will just make sure that the base is square to those guide pieces. After you push it down for a little bit, making sure that it's dry, you can go ahead and pull it up. Then I like to just wipe it down with a paper towel and make sure there's no glue that's going to gum up the works when we try and put the guides back through the saw. And of course, take the blue tape back off your table saw. Then you want to put the sled back in your saw and just make sure that it's running nice and smooth, which this one is. Thank goodness, that would have been embarrassing. Now in all honesty, the glue probably would have been perfectly sufficient to hold those guide pieces to the bottom of the sled. But when you're running things through the table saw, I'd rather not take chances. So I go ahead and hook those guide pieces down with a few additional countersunk screws. Then you're going to want to cut all your side pieces to the appropriate length. Well, scratch that. You're going to want to cut three of your four side pieces to the appropriate length. We're going to start by cutting the back piece, then the two side pieces, and like I said, we're going to leave that front piece long for now. Again, I'll show you why here in just a few minutes. Seriously, just stay patient. You want your side pieces to be sandwiched in between your front and back piece, so just cut them to fit in between those two three-quarter inch pieces. Then with all your pieces cut, I took them over to my workbench and we're going to tack everything together with a 16 gauge brad nailer and some glue. I think this is plenty strong to hold the jig together for what it is. You could always add some additional screws if you wanted it to be a little beefier, but that's probably overkill for this circumstance. Again, I know I've said this like four times already, but we're only hooking together three of the four side pieces of our box. You do not want to hook on the front piece yet. That will be the last thing we do as we're putting the jig together, and like I said, you'll see why in just a second. Just hold on. But another important thing to note is as you're nailing this together, do not put any nails in the middle of the jig or the saw blade will be running or else you will hit those nails with your saw blade and you will probably cuss a little bit. So with three of our four sides hooked together and attached to the base of our jig, we insert it back into the saw and just double check again. Make sure everything is sliding nice and smooth, which it is. Next you're going to want to take some clamps and clamp on that front piece. Just clamp it on. Don't hook it on. Just clamps. We want to be able to take it off here in just a second. Then with our front piece firmly clamped on, you want to insert a dado stack into your table saw. Now the width of your dado is going to determine the width of the fingers on your box joint, so you can make it any size you want. For this we're doing a half inch dado stack. With our dado stack inserted, you want to put your box back on and slowly, with the saw turned on, raise that dado up through the center of your box. We'll eventually cut the whole thing, but I like to start with the center so that we don't hurt the integrity of our box quite yet. Then you need to set your saw blade at the appropriate height. Now you want it to be just as high as the thickness of the material you'll be building your drawers out of. I'm always building my drawers out of 5 8ths Baltic birch, so I'm setting the height of my blade to exactly 5 8ths. Now that our saw blade is at the appropriate height, you can push your jig all the way through, making sure that you cut a nice dado through that front piece. Sorry, my stupid arm kind of got in the way there, but I cut a nice dado through that front piece. Alright, here's why it's important to not attach that front piece yet. With the dado slot cut through that front piece, we then need to remove that piece and cut a tiny little tab that we can perfectly insert into that notch. We know that the height of that tab is 5 8ths inches, so I cut a piece of scrap from a 5 8ths inch piece of plywood. Now you want to cut it kind of long because you actually are going to need two pieces. I'll show you why here right now. So take one of those pieces you just cut. You want it to be about an inch and a half to two inches long, and you want to glue it firmly in place into the pre-cut slot on the front of your jig. It is very important that the piece you cut is a nice tight fit. If it's too loose, it's going to screw up your entire box joint making experience, and you're just going to get frustrated. You want it to be the exact size of the notch that you cut. With that first piece inserted and glued in place, we can then flip around the front of our brace piece and point that little tab towards the saw blade. We're going to hook it in place by gluing and again using 16 gauge brad nails. Now you don't want to position that front piece back exactly where it was. It needs to slide to the left in order for this jig to work properly, hence the fact we didn't hook it in place yet. How far it slides is determined by the width of your dado stack. It needs to slide exactly one blade's width to the left, which just happens to be the exact size of the spacer that you already cut. So using that spacer as a reference, slide your front piece over so that it is exactly one spacer's width away from your pre-cut dadoed slot. And then of course tack it in place again with a 16 gauge nailer on the sides and on the bottom as well. Now with your box entirely hooked together, we can run the entire thing back through the table saw, cutting one continuous slot through the sled as well as re-cutting a dado through your front support piece. Again my stupid arm is just riding the way. Ooh look how nice it slides. And with that you are ready to cut some box joints. So this is how it's going to go. You want to take your stock piece and push it flush against that little peg and just run it through your saw. Then you're going to flop it over that peg and well, you're going to do it again. And you're going to continue this process on down the line until you have cut all your pegs to the end of your stock piece. Now chances are your last cut isn't going to be perfect at the end of your piece. You're probably going to have either a little notch or a little tab and that's perfectly okay and quite normal. So don't fret too much. You see? You see my little tab right there? But that's okay. Then you're going to want to flip that stock piece around, put it back on your tab, and you're going to use this as a reference to start your next piece. Cut your first pass. Then remove your first cut block and just continue on with your second one. Just like that. Now as you can see in this video, my tab is just a little tight. In fact, it might be too tight. So if this happens, you can hit it with a little 220 grit sandpaper to loosen it up just a bit. You just want to be careful because if you take too much off and it's too loose, that's going to correlate to loose box joints. So just take a little off, test it, try again until you get the perfect fit. Now you can see the last pass on my second piece. Instead of a little tab, there is a little recess which will perfectly fit the little tab on my first piece. And at this point, you should have two pieces that are perfectly cut to receive one another. So make them grasp hands. Make them join in a unity that will last for all eternity or until this piece winds up at a goodwill somewhere. See, look, box joints. Now quit watching TV and go make some of your own. Well hot dang, now you can make box joints. If you like that video, please click subscribe down there. 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