Router Table Session 6: Drawer Lock

I have got two ways for you to do drawer locks and corners. And this isn't just about drawers. This is a great way to put any box together. First approach is gonna be using a quarter inch slot cutter. Quarter inch because we're working with half inch material. That relationship is really important. If we're working with three quarter inch stock, we want a three eighths inch slot cutter. So you get the picture here. The slot cutter is half as big as the material that we're working with. Step one, unplug the router. Step two, top of the cutter is made even with the top of our material. and easier to feel and see. Try that for a test cut. Next job, we locate the fence. Now what's gonna happen here eventually is we're gonna make a pass this way. And then with our other piece we're gonna make a pass this way. In order to control our depth of cut here. remember we're all about halfsies. So I'm looking for my quarter inch bar stock. We want our depth of cut to be half the thickness of our material which means we want it to be a quarter inch. We can control that with our quarter inch bar stock. Block one end, pivot the other end. And that is our setup. We're ready for a test cut. So again, what you're gonna see me do is feed one piece this way, that gives us a ton on the end of this piece, other piece gets fed with its face against the fence that produces the groove. I know that's ugly, don't panic. We're gonna fix that. I knew that was coming. Working with Baltic Birch Plywood here. Baltic Birch is a great drawer box material but this is a problem. It's got that chippiness going on. We're gonna take care of that. What we wanna know at this point, is just do the parts fit together? What I'm looking for is, when that tongue goes in that groove, part of my rule is I should be able to slip it in with hand pressure but when I pull it up, they should stay stuck. It's not happening. So that tells me the tongue is too small. What's the correction? If the tongue is too small the bit is down too close to the router table. I gotta raise the cutter just a little bit in order to make the tongue bigger. Gotta raise it, well, probably a 32nd of an inch or so. The other thing we can examine is our fence location. Are we getting a long enough tongue, a deep enough groove? We can check that with our bar stock. That looks great. Quarter inch bar stock, quarter inch tongue. So the only correction we have to make is raising the cutter a little bit. Now I'm not gonna repeat the groove cut 'cause the groove size won't change. That's based on just the size of the bit. I'm just gonna cut another tongue. And before I do that, I'm gonna mark this end, so I don't get confused about which tongue is which. Let's see if I made things better, this is way more better than what we had. This is exactly what we want, slips in with hand pressure, stays stuck together when I pick them up. Now, I promised you we'd take care of that chipping. We're gonna do that right now. We have to make what's called a zero clearance fence. I've already slightly cut into this end of the fence. So in order to zero clearance for my slot cutter I'm gonna spin my fence around, so I have a fresh end. And here's what zero clearance is all about. Start the router, while the router is running, I'm gonna push this in feed only, in feed fence in until it stops. It's gonna run into the ball bearing on the bit, eventually. At that point, we can lock the fence down, shut off the router and move on. Now let's pretend we haven't done anything yet. So these pieces aside, we know we've got a fit, let's see what the cutting process is really gonna look like. Isn't it amazing what a difference it makes when we zero clearance that. So we have that nice crisp cut, instead of that. Significant, very easy to do significant change. Let's take this a couple of steps further. These parts, if I'm making a drawer, the parts like put the groove in or my drawer sides, I would cut this end, rotate cut this end. These parts into which we've put the tongue or my front and back, cut a tongue, cut a tongue. Now, if we're making a drawer or really any box at all we probably wanna put a bottom in it. So let's take this one step further cut a groove for a bottom. Don't change a thing. Grooved face goes against the fence. It's important that you get these pieces facing the right way, and the piece that's got the groove in it, it's the grooved face that goes against the fence and the piece that's got the tongue it's the flat face with no machining on it, that goes against the fence. That gives us that, and then we can put in a quarter inch drawer box. So a couple of things are cool about this. All the work is done with a slot cutter. Once we've got this setup right, what a fast way to put a corner together. In addition to getting the corner put together we can with the exact same setup, get a quarter inch groove in here that will receive the bottom. When we look at the joint itself we've got a mechanical interlock between these parts so that if this is the drawer front and I pull in that direction, I cannot get them to come apart because of the tongue and groove joint. We've got a lot of surface area here. That's great for our glue, so that we're gonna have a great bond between the two. Really nice simple way to put a drawer lock joint together and get the groove for the bottom. Next thing I'm gonna do is show you how you can do a drawer lock with a dedicated drawer lock bit another nice way to put drawers together. Here's another approach to making drawer lock joints and that is using a dedicated drawer lock cutter. This is gonna be similar in that one of our piece is gonna feed horizontally, one of the pieces is gonna feed vertically. But the approach is a little bit different. It's gonna take a little bit more finesse, a little bit more set up, to get this just right. What I like about this is that once we've got it right, it's so fast, not unlike the drawer lock we did with the slot cutter earlier. Here's what we've got going. Here's what you really need to understand about this drawer lock bit. In just a little bit, I'm gonna put it in the cutter, and I'm gonna get it set up in the router table. Here's what I want you to look at while it's not in the cutter. On this cutter, there is a distance from the top of the cutter to this inside corner down here. When I set this in the router table and set it for height I'm gonna try to get the distance from the inside corner down to the table, to equal the distance from the top to the inside corner. It's gonna make more sense when we actually start working with the cutter but that's what you need to understand about dove or drawer lock bits in general. It doesn't matter what style, whose they are, we have to understand that. It is important to know that drawer lock bits are sized based on the material that you're gonna use them with. So when you buy your drawer lock bit make sure it's working with the span of thickness of material that you're gonna commonly use. We're gonna be using this bit with half inch stock and we've got that cutter sourced for you. All right, here's that critical step coming. The fussy part of drawer locks is we need to have the height of the cutter just right, and we need to have the fence location just right. On our previous drawer lock with the slot cutter, you could be a little bit off on the fence location and you'd still be okay. Of course we had to have the bit height just right in this case, both planes gotta be absolutely perfect. And I remember I said what I'm gonna be looking at is trying to get the bit above the table, from inside corner of the table, the exact distance as from top of the bit to the inside corner. And I'm just gonna approximate this by eye and a test cut is what's really gonna tell us what we need to know. I know I'm beating this up but I'm gonna hit it one more time. We've got a distance from here to the inside corner. I'm trying to duplicate that distance from the inside corner, to the top of my router table. And I will say it's a lovely time to have a router lift in the table because of the finite control we wanna have on that cutter. Next thing is our fence. And we're gonna just start by approximating that position because like the depth this way it's gonna be the test cut that really tells us what we need to know about this. I'm gonna narrow up my opening a little. Ultimately, we're gonna zero clearance this for the same reason we did last time, but we're not gonna do that until the height of the bit is right. Fence location, what I wanna do is start out with the distance from the face of the fence, to the tip of the cutter, equal to half the thickness of my material, half inch material, quarter inch bar stock, easy peasy. And I'm not too worried about making this perfect because it's not gonna be right, right now, it's just a starting point and we'll continue to dial it in as we go. All right, we're ready for cutting. Once again, we're gonna go one piece horizontal, one piece vertical. All right, we'll put them together and see what we get here. Assemble like this. Well, it's not too horrible for a first try but it's not a good fit. So looking at that joint, here's what we're getting. The tongue is not bottoming out in the groove. It's not going in deep enough. It's close, but not quite. So that tells me the tongue is just a little bit too big. Now let's look at the cutter set up. When we look at the bit, this piece fed like this. So if the tongue is currently too big, I'll make it smaller by lowering the bit. If the opposite were true. If when I put this together, it was real sloppy, the tongue was too small. I would affect that. I would change that by raising the cutter. Our other problem is that the end of this piece doesn't go to the face of that piece. That's controlled by the fence location. We're working in two planes here. We've got two different things going on. So the easy part is, here on the tongue, if I can estimate my change, this is a direct number. In other words, if I think the tongue is a 32nd of an inch too big, I'll change the height of the cutter by a 32nd of an inch. Here, if I think this needs to come forward, another quarter inch I move the fence half of that, because we're taking a portion off of each piece. And I'm gonna say, it's not quite a quarter, It's probably more like three sixteenths. So step one, we're gonna lower the bit in order to make that tongue just a tiny bit smaller. Again, it's real nice to have a router lift for this so I can really finesse my change. Now we wanna move the fence back, half of three sixteenths. I'm going to make a mark on my table. I wanna keep track of my net change, so, I'm gonna do two marks on the table, one on each side. That's my starting point now, same thing over on the other end. Now from that position, we'll go back 330 seconds or so. And then to keep track of my work, I'm gonna mark these ends, this was cut number one, cut number one second verse, same as the first. Nice, I think we might've got it in one change here. So as I put this together, does the joint come together the way it's supposed to with no gaps? That looks really good. Now in this case, one of my joint tests is pressing them together and they're gonna stay stuck because of the tapered shape on these tongues. That rule doesn't really work for drawer lock bits like this. Looking in the other direction here, this isn't horrible but I'm gonna change the fence just a little bit. This is a little too much overhang. I do like having this end grain project past this face grain. And then when the joint is glued together, I would come back and clean that up with a flush trim bit or through some sanding or a black plain, if it's solid wood but that's a little more overhanging than I want. So I'm gonna bring my fence forward. It's nice having those pencil lines on the table. 'Cause the pencil line show me where I started, now I know where I am at this second. So I'm just gonna loosen one end, and I'm gonna pivot back toward my pencil line, on my end here, just a little bit to effect a change. It's the finger tap, micro adjust. And I think it's safe at this point to take our next step which is let's go ahead and zero clearance our fence. Same procedure we did before, run the cutter in feed side only, push the fence in to capture that cutter. Let's try the real deal. Nice, here's what we've got. We got your mechanical grab. We got your glue surface. Lot of things going on that make this a really good joint for drawers. And it's so fast to make, once we get this setup. Now let's talk about setup. What's cool about the drawer lock bit, is that the height of the cutter which we now know is specific to this bit. Once we know that height, that height is always correct regardless of our material thickness. This is half inch Baltic Birch, if the next time we work with nine sixteenths, that height is still gonna be exactly the same, because the tongue size is always the tongue size. "What changes?" he asks. If I go to a thicker or thinner material, give you a second to think about this. Fence location is the only variable. So now that I know the right tongue height, save this piece and use that as a gauge to set the bit the next time. And you're gonna be much closer on your first attempt. Then all you have to do is adjust the fence based on the thickness of your stock. If you're working with narrow pieces maybe you're making a tool chest that's got two or three inch drawers in it, start with big wide slabs like I'm doing here, do the drawer lock joints in the end of the pieces then take them to the table saw and rip those narrow parts out of them. What a fast way to make a drawer. So I really liked the drawer lock a lot, little bit fussy to set up first time until you do it. But once you get the hang of it, it goes pretty fast. That takes care of our setup and drawer I hope. Let's give you one more thing before I forget here. And that is, which part is which here? We should know that, right? So when we look at our pieces, and they come together like this, which is the front and back and which is the sides? The parts come together this way, so I can of course disassemble them in this direction. I can't disassemble in that direction because I'm pulling against the mechanics of the joint. As a result, the piece you feed horizontally will be your drawer from back. The piece that you fed vertically will become your drawer sides. That then takes care of our drawer lock bit. Two opportunities here, two different ways, you can do drawer locks on your router table and both of them provide great mechanical advantage, as we bind that joint together, additional glue surface, rock solid corners for your drawers and boxes.