- [Voiceover] The Wood Whisperer is sponsored
by Powermatic.
I recently wrote an article called
The Process is the Project, and it outlined
the four phases of designing and building furniture,
at least the way that I see it.
Today, what we're going to do is expand a little bit
on that second phase, which is engineer the design.
Basically, you've come up with something
that looks the way you want it to look.
How does it go together?
How do those joints play together?
I'm going to be building a chest of drawers
and a nightstand upcoming in the Wood Whisperer Guild,
and this was an opportunity for me to look
at an interesting joinery situation
and just kind of explain a little bit,
using SketchUp and a voiceover,
to show you exactly what my logic is
to why the mortise and tenons
are sized the way that they are,
and you can kind of apply this logic to just
about any part of a project in the future.
Oh, and by the way, if you like the concept
of The Process is the Project,
the graphic we made for it looks so cool,
we made posters out of it,
so if you want one of those, we actually have those
up at our store at twwstore.com.
All right, so, let's talk about joinery.
- [Voiceover] Hit it!
(boppy music)
- [Voiceover] Whenever designing furniture,
you have to balance what you want
with what's actually possible,
and there's usually not just one right answer.
There's a lot of different right answers.
You just have to go through and play with things
and see how it turns out.
But the way that I look at it is
it's sort of a three-step process.
First, I design what I think is best
for the quality of the piece.
What gives it the most strength
or achieves the goal we're trying to achieve with it?
Then you have to put that through a filter.
You have to adjust for restrictions.
There might be things where one part
meets another part that, when you look
at the part alone, you don't see the problem.
Put two parts together and suddenly, boom,
there's a problem, so you have to adjust
for the restrictions of the piece.
And then you can simplify where it's sensible.
Having different size tenons all over the place
might seem okay in SketchUp, but once you
get that into the shop, that's a real
pain in the butt to execute.
So getting things to be similar from one part
to another is always good.
So let's jump into this particular project
and talk a little bit about some of the joinery,
the tenons, specifically.
Let's take a close look, because the night stand
and the dresser are pretty much the same.
We'll put on a little x-ray view here
so we can see what's going on in the interior.
Change the face style to x-ray.
I've got a nice assortment of stuff here.
There are double tenons coming in from each side.
You can see there's a little piece
of the top panel that's there as well.
But we're really focused on those tenons right now.
You can see, they're different lengths, right?
In fact, those are actually mortises,
because these are going to be slip tenon joints.
Let's take a close look
with the rest of the stuff out of the way.
It makes it a little easier to see, right?
Different heights, different depths.
How do we arrive at that?
Why did I end up with something like this?
Let me change the view back to normal.
Just to show you, here, again, on the inside,
this little stubby one is a little bit shorter,
and also a little more shallow, right?
The bigger one is definitely doing
a lion's share of the work holding here.
Let's go to a blank.
This is kind of where you would start, right?
You would say, well, I've got my inch-and-three-quarter
by inch-and-three-quarter leg,
and I want to put a couple of mortises in there.
Again, it's going to be a slip mortise and tenon
or lose tenon joinery here.
I'll just grab my measuring tool.
This is going to allow me to put
layout marks where I need them.
Just going to say two-and-a-half inches up.
That's the mark for the top of this piece, right?
The rail that adjoins it.
So that's just for reference.
I want my tenon, let's say,
let's start about three-eighths of an inch.
I just kind of pull nice numbers
that make sense to me.
Quarter inch, three-sixteenths,
three-eighths is a little heavy,
but these are big pieces,
so I'll go with three-eighths here.
And we'll go up from the bottom three-eighths.
Let's go in, because I want to do two tenons here, right?
This is inch-and-three-quarter.
You can do one tenon,
but I actually think two is going to be better,
if you can pull it off.
I keep saying tenons, but really I'm talking
about mortises at this point, right?
So three-eighths in from the edge.
Three-eighths in from that edge.
And I want two tenons within this space.
Each tenon, I'll make it three-eighths of an inch.
All right, that looks pretty good.
Let's make the actual mortises here
by taking the square tool and using our layout lines,
which are there waiting for us.
Woops, you know what?
I got to be within the component to do it.
That's better.
There's one.
There's two.
Now let's push-pull this surface
to actually create the mortise.
Now, how deep do you go?
Well, this leg is an inch-and-three-quarters.
Generally, I don't want to go past what would be
half-way through the thickness of this piece,
so let's say seven-eighths, just as a nice round number,
that is half, all right?
Seven-eights.
We'll do this one seven-eighths.
All right, not too bad.
Now, for me, I would say that's close,
in the ballpark of the family of what would be
like the ideal mortise for the pieces of this size.
That looks pretty good to my eye.
So, what's the problem?
Well, now we have to go to that next step,
where we adjust for restrictions.
One such restriction is what about the crosspiece
coming in from the front?
What happens when you have the same size mortises there?
Here's a good example.
We've got both mortises on both sides.
Doesn't look too bad.
It's hard to see exactly what's going on,
so let's turn on the x-ray view
and see what we've got.
Oh, boy!
Now, these outside mortises aren't too bad,
but look what happens to these mortises.
If you put a tenon through there,
that tenon's going to collide.
So that is just not going to work,
so we immediately know that we have
to make some changes here.
A couple different things that we can do.
We can shift the tenons toward the outside of the leg,
giving us a little bit more buffer on the inside.
We can shorten the depth of these two tenons
so that they don't touch one another.
We can also shorten the depth of this guy
if we think that's going to be a problem, too.
If you look right here,
this is the actual set of mortise and tenons
that we're going to be using,
and I'll give you a little bit better idea
of why I made these decisions.
This guy is nice and short,
but there's a secondary thing we haven't
talked about yet, and that is
some of the supports for the drawer, right?
There's going to be a support that goes into a rabbet.
If this rabbet is here,
there's not that much material to play with, right?
It makes sense when you look at the rail,
if this mortise were really, really high,
it would interfere with this rabbet,
so that's why this mortise is now chopped down
to about an inch, like that.
The depth is pulled in by quite a bit.
We're only going three-eighths of an inch in,
and that allows these two mortises to exist
and co-exist next to one another
without being a problem.
The total length of the mortise
I did trim down a little bit.
It's only an inch-and-a-half.
But, you see, this line up here
represents the top of the adjoining rail on the side,
and then this is that three-eighths where we drew
the start of the mortise in the original,
and look how much down I am from that, all right?
So I took it in a little bit.
The reason for that is because we have
a side panel that's going to go right in here.
If that panel is in this groove,
we don't want that groove to make contact
with this mortise, so I brought it down a little bit.
Everything is a compromise.
Whether this is one inch or an inch-and-an-eighth
or an inch-and-a-sixteenth, that's where
the third step of simplification
and sensibility comes in.
To me, I like nice round numbers,
nice repetitive numbers,
and consistent numbers throughout the piece.
So if I have a one-inch mortise here,
any time I need a small mortise,
I'm going to try to get that same one-inch mortise.
It's just going to make it easier to batch
this stuff out when the time comes.
Hopefully, this gives you an idea of how you might
adjust your tenon sizes and various joinery sizes
in a sensible workflow within a project.
(gentle music)