108wood joint tour

In this video, I want to introduce you to a handful of interesting woodworking joints

These aren't necessarily things that you'd want to use as a rank beginner

but you really should know about them because as you progress in woodworking

these joints are going to offer you opportunities for all kinds of creative expression that you're really going to like

So, I first want to start talking about what are called dados and rabbets

A dado is a three-sided groove, and you can see it up here, and a rabbit is a two-sided groove

The three-sided groove is most often used in, say, some kind of a cabinet or a bookshelf or something like that

A groove like this would be cut into the sides, and then the ends of the shelf members

the parts that are horizontally oriented, would fit into those grooves, and the ends would be supported because it's fitting into a groove

and also the surface area of the connection is larger because now you're not just operating off of a one-face contact

but there's three faces contacting each other. So, in this drawing here, you can see a dado groove being cut by a router

So, here's the groove here. Here's a frame which guides the travel of the router

This is the router base here, and that's the router bit, and it's traveling in that direction

The bit is spinning, and it's chewing a groove in the wood. So, that's one way of cutting dado grooves

A more traditional way would be with a saw and chisel, which you see here

So, the saw would be used to cut, by hand, would be used to cut a slot here and a slot here of the depth that we want the groove to be

and then the wood in between is removed with a chisel. That's kind of the traditional way of doing it

It's slower and more skill-dependent than the router method, but works perfectly well

It's actually good to get practice with that kind of thing. I'm a big advocate of struggling for a while, especially honing your skills with hand tools before just jumping right in and using power tools

which do tend to make things quite a bit easier, although more expensive, noisier, and dustier, too

Now, down here, we can see the rabbet groove being cut. Now, this is a router mounted in a table

So, that red bit you see here, it's the same sort of bit that you see up here in a router that's being used freehand

But in this case, the router is mounted upside down in a table, and instead of the router moving, the workpiece does

And in this case, we have what's called a fence here. The fence guides the workpiece and keeps it in the same position relative to the router bit all the way along

so you get a nice, even, two-sided rabbet groove. You can cut the same sort of thing with a table saw as well

You can make multiple passes with the table saw to cut the width of groove you want

or you can use what's called a dado blade. This is a wobble dado, as it's called, which means that the blade actually wobbles back and forth as it spins

in a kind of controlled way, and depending on the amount of wobble you dial in

you'll get a wider or narrower rabbet joint, rabbet groove. The dado blade, of course, like you'd guess from its name, can be used to cut dados as well, in the same sort of way

Here you can see a dado groove that I cut in a piece of pine

I cut it after I finished the piece of wood, actually. There are a couple of reasons for that

This was a small wall cabinet, kind of a bookshelf kind of thing I made for the bedroom of a couple of my boys

I finished it with a blue stain, actually, and then several coats of urethane

and then I cut the dado groove that will join this to the side pieces

It just happens to show what a nice, crisp dado looks like

highlighted by the fact that the blue and light wood contrasts each other

Here you can see a completed dado joint in action. It's actually a mock-up. It's not part of any real piece of furniture or anything

but you can see how it goes together. This is a nice, tight one

It's pretty well a textbook example of what a dado should look like

I've made this using Baltic birch plywood, which I've mentioned to you before

It's a premium plywood made entirely of hardwood laminations, birch. It's very hard, very strong

Even the edges look good on this stuff, so there's a dado in actual action

Here I am using a tool I created called the dado engine

Now, if you look here in the center, this piece of wood that you can see extending

kind of here, you can see it here and here and here, that's an actual workpiece that I want to cut some dados in

It's going to be a shelf. These strips here, this one, this one, this one, this one, and these two here

are guides for the router, and the space between these pairs of wood, pieces of wood, is adjustable

I can adjust that space to whatever I want, and the way the dado engine works is you put your piece of wood in here

the piece of wood that's going to be the shelf, and you close the side strips around that piece of wood tightly

and these two strips guide the travel of a router bit that is making a groove in this bottom piece

But because the space between the grooves is customized, it's made to fit your particular shelf material

you always get an absolutely perfect fit, even when you're using sheet goods that are undersized from standard

And all sheet goods do seem to be a little bit smaller than they're supposed to be

So that can be a problem, and there's also a certain variation

You might have a sheet of plywood that's a certain size one time

and the same, supposedly three-quarter-inch thick plywood is actually a little thinner the next time, or a little thicker

So you can't rely on just one diameter of router bit to cut dado grooves that are really nice and tight

That's where the dado engine comes in. It's adjustable, and very fast, too

It does a great job in very little time. Here's another shot of a rabbet joint

This would be the edge of a piece of door material. So the holes here are for dowel joints

and the groove here is for accommodating a glass panel that fits in

with enough extra room over here for the installation of a strip

all around the opening to hold that glass in. Here we've got the spline joint

and I'm showing it in a disassembled mock-up of a frame and panel door

So I use this mock-up when I'm doing live seminars, and it shows one way, one nice way of putting together a frame and panel door

When I say frame and panel, I mean the frame. This is a frame member here, another frame member here

another frame member there, and then the panel is in the middle

This is called a style. So the vertical pieces of wood that form the frame are styles

The horizontal pieces, top and bottom of a door, for instance, those are called rails, and you need to connect them in a frame

and that's where the spline joint comes in. So this groove you see here, that continues all the way down the length of the wood

and it's mostly for accommodating the panel, which interlocks in that groove

But in the case of the rails, we take the groove. Now the groove exists here too, in this plane

because we have to accommodate the end of the panel. So in this case, we extend the groove, so it continues here

and then we wrap the groove right around the end of the rails

The width of the groove is exactly the same as the thickness of this spline, it's called

This happens to be a piece of oak that I cut up for this purpose

The grain runs this way, which is the way it has to run in order for the spline to be strong

If I made the spline so the grain ran this way, this wouldn't be strong at all

because wood is not very strong this way. You can break it apart easily, and that's the direction that any force would be applied in the assembled joint

So we have the grain running this way, and it makes for a very strong spline

Just a couple of things here, also advanced, sort of teaching tangent kind of things

but I want to alert you to them. This panel, the beveled edges here, the feature that turns this from a regular rectangular piece of wood

into an actual raised panel, is this bevel here, and I really like to cut those with a hand plane

I start with a table saw to hog off most of the waste, and then finish up with a hand plane

You get a really nice bevel, it's very traditional looking. You can't reproduce that with a router in a router table

which is usually the way people make raised panels in small shops, so I really like that method

And you see the dark stain here on the edge of the panel

You should apply that stain before you assemble your doors, because the idea with the frame and panel construction is that this wide expanse of solid wood

is free to expand and contract seasonally. So it's going to shrink when it gets dry, it's going to expand when it gets moist

that's going to happen back and forth every year. So you don't want to finish your door with stain

only to have the panel shrink and reveal some light-colored unstained wood

So that's why you want to wipe a little stain on the interlocking part

before you assemble your door and finish it. This is called a wing cutter, or a slot cutter

and this is the very tool that I used to create those slots that you just saw in the stiles and rails

So the slots that accommodate the panel, and also that slot that continues around the end of the rails

to make room for the spline. Dovetail joints. So this is an old box, and the corners are joined with dovetails

The reason they're called that is because of the angle. If you look at this outline right here, it kind of fans out, kind of like a dove's tail

So that's why they call it that. These dovetails were probably hand-cut based on the look of the age of the thing

And here's another example of some dovetail joints. This is a cherry wood box that I made just when I was at the tail end of high school

I made it about 40 years ago, actually. It's been around a long time

Oil-finished cherry, hand-cut dovetail joints, and a carving in the top. I made this as a Christmas present for my girlfriend at the time, and she turned out to be my wife

so I guess the dovetails worked, right? These dovetails are hand-cut, and I wanted to make it absolutely clear to anyone that looks at this box

that these are not machine-cut. I cut these with a handsaw and chisel and nothing else, so it's kind of a bit of a show-off joint

It takes a long time, and you have to be very careful in order to do a good job

But the thing that makes them hand-cut for sure is the very, very narrow part of the joint here

It's just enough to get a handsaw in to cut those joints

You can cut dovetails with a router and a jig, but you can never cut them with a very thin little section

to the joint, as you see here. So it's kind of a hallmark of true hand-cut dovetails

This is kind of a cousin to the dovetail joint. This is called a finger joint

And the parts interlock, just like with a dovetail, except the interlocking parts are rectangular

They're not angled. Now, this makes it considerably easier to prepare this with a machine

And the joints you see here are the sanded version of this

So when you actually make a joint like this, you specially design it so the overlapping, the interlocking

kind of extends a little bit beyond where it needs to. And then you sand these protrusions off flush

That's how you get a nice, even finish on the outside. I made these joints as part of a project building a coffin, actually

These are pretty big joints as part of a pretty big project

And I happened to use this machine to do it. This is a kind of a router table where the router slides back and forth

So the workpiece sits down vertically. It's sticking way up beyond this

You cut your first slot. There's this indexing pin, which is fastened to the router table

You slide your workpiece over. You put the newly cut groove on top of the indexing pin

And then you cut another groove. And then you pick it up and you move it over and you cut another groove

And you pick it up and you move it over and you cut another groove

This way they're all exactly the same spacing apart. And if you've adjusted things correctly, they just fit together perfectly

This is a joint I've never seen anyone else do this, at least not the way I do it

I call this the brass pinned joint. And it's something that you sometimes see in old tools that are made of maybe wood and metal

Old furniture sometimes has this. I'm not sure how they did it in the olden days, to be honest

But I know how I do it and it works really well. This happens to be a piece of walnut

And I chose that for this example so that the brass really shows up nicely

So let's kind of open the hood on this and see how we do it

You start by drilling matching holes in two pieces of wood. So let's just go back for a minute here

This is actually a corner. So there's one piece of wood that you see here goes in this direction

And then there's another piece that runs 90 degrees to it. So the edge of a box or something like that

You drill holes in this part of the work and then also in the end of the corresponding piece that's going to form the corner

And then you drive a steel screw all the way in and all the way out

And the reason of the same size as the brass screw you're going to use that will be the actual pin

The reason for this is because brass screws are very soft. And it's a very disappointing thing when you try and drive a brass screw into a joint, especially in hardwood

And the fit's a little bit too tight and you get partway along and zip, that brass screw breaks

You can't really get it out. You can't make it look nice

You really just have to start over again. So that's a bad thing. You don't want that to happen

And pre-drilling, pre-driving a steel screw in here really helps out. So you drive it in, drive it out

It cuts some threads of a sort in the wood and then you can drive your brass screw in with more confidence

You still, if you're applying more than a little bit of pressure to that brass screw

you might want to think about drilling that hole out a little bit, making it a bit bigger

because it's still possible to break the brass screw after you've done a kind of a tapping of the threads, so to speak

with this wood screw, the steel wood screw, but it's a great policy, great practice

And this is what you want things to look like just before the last stage

This was the, I guess you call it the leg, the central leg for a wooden music stand that I made

And this is the head, the slot head of a brass screw

It's a countersunk design, so the head itself is kind of angled a bit

And you can see there's a slot here. Now the slot is just a bit above the surface of the wood, as you can see, and that's very important

Because what happens next is that you use a power sander, a belt sander

That's really the only kind of sander that's going to work on this. And you sand off the brass, so that all the brass that's remaining is flush with the wood

So you get rid of all this excess stuff, you get rid of the slot, you bring it right down to the surface of the wood

and that's what you end up with when you're done. And it looks great

There's just one thing I need to warn you about. The brass screw can build up a lot of heat from the friction of sanding

It's really surprising. So you want to sand a little bit and then stop and let that brass screw cool

When I say sand a little bit, I mean sand with moderate pressure for, oh, no more than five seconds

Say five full seconds, that's probably about enough. That brass is getting pretty hot by that time

Let it sit for five minutes to cool off. The brass doesn't cool off very fast because it's completely surrounded by wood, which is a pretty good insulator

So five seconds of sanding, five minutes of waiting, and you just repeat that back and forth

until your brass screws are flush with the wood and they look terrific like this

If you don't do this, if you ignore me and you just sand for more than five seconds or so

that brass is going to get hot enough that it'll actually char the wood right around the perimeter

And that looks, it not only looks bad, but you can't fix it either

because the charring goes right down, well below the surface. So take your time, be patient, and that brass pin joint is going to work out really well

There are millions of, well not millions, there's a lot of woodworking joints in the world

and I've only touched on kind of the main ones here. If you have a woodworking challenge and you're looking for the ideal joint to meet that challenge

let me know. We can think about it together and I can make some suggestions that might help you out