Leg to Rail Joinery Methods

On a project like this table. What we've got here is leg to rail joinery bringing these parts together on all four sides. So they actually eight joints in this thing. And what we wanna do is make sure that that joinery is sound. So what I wanna do is provide two different options for you on a project like this. That'll let you do leg to rail joinery in your shop. First, let's talk about dowels. On this leg, I've already located where the dowels are gonna go. Easiest way I found to make sure that you accurately get the same dowel locations on both components, meaning the leg and the rail is to get them marked out on one part, then take the mating part and simply transfer those marks. Now, the other thing I wanna do is label a pieces so that I know they go together. So this is gonna be rail A, upside down to you but it looks good to me from this angle. And this is leg A and as I work my way around, the next one will be B, C, D E all the way up. Just in case these lines are a little bit different from face of the leg to face of the leg. Next thing I'm gonna do. I've got little hash marks on there. I'm gonna extend those lines a little bit using my square, just so that they're easier for me to see. Now here's the deal with being able to see those lines. I'm gonna drill these holes using what's called a self-centering drilling jig or dialing jig. The deal with this is that across the jig there are a number of different holes in this guide. Each of those holes represents a different size drill bit. I'll be using three eights for this, because as a general rule, I want the dowel to be about half as big as the thickness of my rail. So I'm gonna use a three eight style, on my three-quarter inch rail stock. When I position this, it's critical, imperative that I position it correctly. And the way that's done is that, on center with the guide hole, there's a hash mark down here. That hash mark has to be perfectly located on the pencil line on the leg. Now you can imagine that on this line, if I miss it just a little bit this way, and this line I miss it just a little bit this way. Then when I put my dowels in and try to get everything to come together, it's not gonna come together. So really take your time at this portion of the project, and very carefully do that alignment. Now, when I close this up, self-centering means that, that drill guide is now perfectly centered on the leg. Next we can drill one hole, wanna make sure that I don't drill too deep. So this is about as low tech and easy as it gets. I've got a piece of masking tape indicating my depth of hole. When the tapes, even with the drill guide, I'm done. Same procedure for each one. That gives me my $3 for the leg. Next thing I have to do is repeat this process on the rail. Once again, I'm centering that hash mark on the three-eighths guide hole, right on my layout line. In this case, your best bet is gonna be to have your stock and a vice or a clamp, so that it's secure. Couple of dollars in there and we're set to go to join those components. Now, of course, there's good news and there's bad news. The nice thing about dialing is that the self-centering jigs are relatively inexpensive for the price of a jig and a drill bit to go with it. You're set to go on your joinery. The downside is that you have to be really, really meticulous, about making sure you get the alignment just right on those parts. So next thing I wanna show you is a biscuit joiner. And you'll see that this gives you a lot of latitude on how you bring your parts together. So here's the way I'm gonna lay this one out. I'm gonna set my rail on top of the leg. That line defines the bottom of the rail. I'm gonna be using biscuits to join this together. Now, biscuits come in different sizes. We wanna use the largest biscuit that we can for the work. So I'm gonna see if I can get two, number 20 biscuits in there, just like that. That's gonna work just fine. And then really I'm just gonna eyeball the center of that one. Get my other one on here, eyeball the center of this one. I wanna bring those lines to the edge, so that I can bring my rail here. And transfer those lines onto my rail. So, pretty down and dirty layout, but it's gonna work out just fine. On the biscuit joiner itself. The way it works is that there's a cutter in here. It looks a lot like a table saw blade, smaller diameter. And that cutter is gonna penetrate our stack and leave a slot in there that's just the right size to receive the biscuit. So I've got to check a couple things. I wanna make sure I'm on the number 20 biscuits setting. I wanna make sure that my fence to cut her location is half the size of my material. That's gonna get me right in the center of the leg. I'm gonna wrap this clamp from over here. I think it's important that you have two hands on the biscuit joiner. So I wanna make sure that my stock is securely clamp. And for this biscuit joiners, they are a little louder than cordless drills. So I'm gonna put on a set of earplugs for this one. The process gets repeated except, that for the rail, because it's thinner. I need to change my setting. So that I'm in the right spot to be in the center of three quarter inch stack. Instead of that thicker leg material. Once again, I'm gonna clamp my work to the bench. When I bring the biscuit joiner here. What I'm looking at is the line here and the line here which indicate the center of the cutter. So the layout lines I put on my material are used as an index to control the position of the slots. It's a lot more forgiving than the lines on that biscuit around the drill guide. So now if I do a number 20 biscuit and a number 20 biscuit, and I bring the parts together. Our leg to rail joinery is complete. Now what's cool is that, look at the lateral adjustment provided by a biscuit joiner. Once those dowels are in the other joint, there is no wiggle room top to bottom like this. And remember I said, if we miss those holes just a little bit, you're gonna have a hard time getting things to go together here. If I miss my lines by a little bit, I'm still gonna be able to get this part together and real important, get the top of the rail aligned with the top of the leg. So both are great options for leg to rail assembly. Drill index, self-centered drill guide is lower tech, maybe a little bit more accessible to your pocketbook. Biscuit joiner, a little more dough up front, but ease of assembly is significantly greater than it is with dowel. So check them out, find the technique that works best for you in your shop.