Dovetail Jig Session 1: Setting Up

Dovetails are great and woodworkers like to incorporate them in their projects for a couple of reasons. One, they do add a great deal of strength to a box, a drawer, whatever object we're putting together. Also, they look wonderful. And it's really gotten to where when woodworkers or end users are looking at something, they like to see the dovetail as a sign of quality that was built into that project. So we're gonna look at cutting half blind and through dovetails on a standard dovetailed jig. A couple of things here. One we're using a Porter-Cable dovetail jig. Don't sweat it if you don't own a Porter-Cable dovetail jig, because much of what we're talking about here is compatible across the board. We're gonna talk not about how to use this jig, but in general, how to set up jigs, so that you can effectively cut dovetails. The cutting techniques we show are gonna be helpful, so it doesn't really matter what kind of jig you have or what kind of router you're gonna use. Let's start out with getting an overall feel for these jigs and what they're all about. A little bit of jargon. The horizontal surface here is typically called a comb or a template. And that provides fingers that our router can follow in order to create our joint. In our case, we're gonna use two different templates, because we're gonna do both half blind and through dovetails. And if you're not familiar with half blind versus through yet, don't worry about it, we're going to talk about dovetails. This comb is going to be for our half blinds and later we'll take that one out and put this one in and that's gonna be for our through dovetails. Now, it'll be important with your jig to know what router bits your jig calls for it, 'cause typically the bits are jig-specific. So you really gotta read the owner's manual, painful though that may be, and find out what specific angle on the dovetail bit and diameter, and the diameter refers to the distance from tip to tip across the bottom of the cutter. So the specific specifications for your jig's dovetail bit, that you gotta know that. We only need one bit for doing half blinds, but when we do throughs it'll be a two bit operation. We need the dovetail bit and we need a straight bit. Same thing there, you gotta know for your jig what bit you're gonna have to have. Then, you might wonder, when I was, when those bits are in my router what prevents them from cutting into our template that we need? And the answer to that is a standard router accessory. These are called guide bushings or template guide bushings. We'll mount these into the base of the router. And when this is in the router the way it works is that that shoulder can follow our comb. So, again, we're gonna need to know for your jig what size guide bushing they tell you to have. You'll have to look in your manual. This one is not the right one for this application, because it shouldn't be wiggly like that. It's this one that goes with this comb. So the way that works is that the shoulder can trace the fingers and prevent making contact with, prevent the dovetail bit from making contact with the aluminum. If you don't have this size right there's no way the dimensions of your joint can come out correctly. From there, let's talk about the stopping device. There's gonna be some kind of a pin or other guide that's gonna control the location of your material. And we'll talk about this a lot as we start using the dovetail jig. In this case, that stop is adjustable. Some jigs have that feature, that adjustability. On other jigs you may find that the stop pin here is in a fixed position and you're going to butt your material against that one fixed stop every time. We'll talk often about the importance of using these side stops in order to register your material correctly. It's important to notice that the side stop and the horizontal stop have an offset built into them, and all jigs are going to be that way, and that's correct. That's the way that we use it, that needs to be that way. So that's not a problem, it's a benefit. So that's our side stop and we'll talk more about it as we're using the jig. Then additionally, we're gonna need some way to hold our material in place. And that'll vary from jig to jig. It's not uncommon that some kind of a cam action connected to a handle is gonna put pressure and create a vice type action here that lets us easily take material in and out of the jig. How about our router? Now in this case, Porter-Cable jig, Bosch router, that's just fine. We don't need any kind of a compatibility of brand between the two. It doesn't take a lot of horsepower to cut dovetails. So anything around 1 1/2 horse, which would be 10 amps or so on the motor is gonna be just fine. The big thing we need in the router is the ability to accept those guide bushings that we just got done talking about. So when we look at the bottom of this one, it's got a ring. And if I grab a guide bushing, you'll be able to see that our guide bushing goes into the shoulder in that ring, and then there's a neural nut that'll go on the other side to capture it. So big deal with the router is just its ability to accept a guide bushing. That gives you an overview of dovetail jigs, the jargon of the parts, so that we can move on and start getting our jig and material ready to start cutting dovetails. Let's have a look at a few things you gotta do before you cut a dovetail to make sure your jig and your material is ready for that step. The dovetail jigs themselves generally are pretty much turnkey. You take them out of the box, maybe put a couple of parts together, not a big deal. But woodworking tools in general, one of the things I've found really, really, really helps is to lubricate the surfaces. And the key to this really is that we need a tool-specific lubricant. What do we not want? Extra points if you get it right. We don't want anything with silicone in it. And the reason for that is that silicone on your tool surfaces can migrate into your material and basically it'll seal the surface and you'll find that out when you go to put on stain or a top coat. So we wanna make sure that we've got something that's specifically set up for this. We've got this sourced for you in the PDF that accompanies the class. What this stuff will do once we apply it here and to the router base is to just help everything move a little bit more easily. Of course, as we're rubbing our router base on the dovetail comb, there's a little bit of friction. So this is gonna help reduce that. It's really easy to apply. Spritz it on, let it dry. And do the same thing to our router base. And let it dry, that's like, in the time it took me to say let it dry, it's dry. This is something that if you already own a dovetail jig and you've never done this, once you spray that on and use the jig the next time you're gonna be amazed at what a difference it makes in these parts gliding across each other instead of hanging up. That's about it for getting your dovetail jig ready. And we'll talk about alignment to that stop pin and that kind of stuff. That's more to do with specifically cutting a dovetail. Your material. Here's the big thing. You are not gonna get a good dovetail if you don't do a good job cutting your parts. We have to have smooth, straight square. We've gotta have ends that have been jointed or otherwise made nice and straight. We've gotta have ends that are cut square in both directions, meaning perpendicular to our edge and perpendicular to the face. And if you've not done a good job getting that material ready, when you put it in the jig it's not gonna line up right and you're gonna have a horrible time trying to get good dovetails out of it. So it's not complicated. A little bit of lubricating on the jig, careful cutting on your parts. If you're cutting a four-sided box, you have to make sure that parts that are supposed to be identical are identical or the dovetails aren't gonna go together correctly. So take your time on material prep, make sure you got everything right, do a little bit spritzing on your jig, and you're gonna be ready to go for setting up and cutting dovetails. Let's have a look at a couple of different types of dovetails and talk about parts of a dovetail, so when we're using this jargon, you're with me. First thing we're gonna look at is what's called a half blind dovetail. I'm gonna point out right away the grooves for a drawer or box bottom are kerflooeyated in this one, ignore the grooves. We're just looking at the joint. On a half blind dovetail, what makes it a half blind is when we look at it from this side, we can see the joint. When we look at it from this side, we cannot. So the way to remember that is we can see the joint half the time. In a drawer, this would be the drawer box or the drawer side, this would be the drawer front. Through dovetail. And we're gonna cut both flavors of these joints before we're done here. On a through dovetail we can see it here and we can see it here, because the mating pieces each project through each other. This is the end grain of the horizontal. This is the end grain of the vertical. If we were making a drawer, this would be the drawer side, this would be the drawer front. Now how do I know that? Well, because of the parts of a dovetail. So here's what we've got. When we cut a dovetail, oddly enough, we're gonna cut tails, that's this component. It's the male or the positive part of the joint. We're also gonna cut a negative profile. That's pins and sockets. The hole that the tail goes into is our socket, next to it is a pin. And we can take this one step further and we need to, 'cause we're going to talk about this, this would be a full pin, this would be a half pin. The difference between the two, the half pin is only angled on one side, because it's the last part of the joint. So very commonly half pin socket, full, with another half pin at the other end. And that's gonna figure in when we start laying out our joints on the dovetail jig is to achieve a half pin on each side here in our throughs, and we've got the same thing going on our half blinds. Now what makes this the drawer side? It's a little bit easier to see on our throughs. When we put a dovetail together part of the attraction to this is the mechanical grab that we get and the great amount of glue surface. Mechanical grab is that I can slide them together or tap them, in this direction, but no matter how hard I pull now this way, if I pull on the horizontal board, I can't separate those, because of the angle of the dovetail has them keyed together. That's what makes my horizontal board here the drawer front and this one the drawer side. Even if I didn't glue the joint, which I'm not advocating, I'm not saying you should do that, but even without glue on the joint, I can't separate them. When I pulled down and up, I can't get them apart. If I inadvertently make the tailboard the drawer front, it's possible if the glue fails we could pull the drawer front off the joint. So you wanna make sure that you're using them right way. So pins and sockets, half pins, tails are the parts of our joint. Through and half blind are the types of joints. All the work that we can do here on our jig.