I'm going to show you how to make a
mortise and tenon joint this joint is a frame joint it's one we
use throughout furniture making and this I'm going to make a mortise
hole in this one and the tenon in this one using a handful of tools and first
off I'm going to take this just to give me a distance here like this I'm pencil
line and I'm pencil line just two marks to get me in close approximation to
where the mortise hole is going to go pull the two lines across the whole of
the surface transfer onto the adjacent face across the whole face so that you
can transfer to the opposite side this is going to show the delineation of
the width of the mortise so we're going to cut an elongated hole in here from
this side and the other side so on the end of this piece that's going
to go into this so this is going in here I want the
distance of the thickness it's going to go
through in this case so again just finger on the outside
flushing it with the outside edge and a small mark and the rest is all done
with the square check your corner to make sure you line up on the corner, this one is lining up fine but it's actually not
the finish line that's just a rough guideline that I'm going to use to run
my pins to form the distance of the thickness of the tenon so let me take
you through that step I'm going to cut a half inch mortise and
a half inch tenon, it's going to be made to the width of this chisel this is a
half inch chisel which is about 13 millimeters so I go right in between the
tips of these two pins not the base but the tips so I am just in between those
two points I don't want to be over by very much if at all I do have to go right in
between the very tips there so I'm right in between the tips so now these two points have to be
equidistance from both sides so I eyeball this distance here first from
one side and then the other and I move the beam to get the pins eyeball to
center that's just a guess to get it to the center and I make two pin points in the
surface here then I take this and I come from this side to see how close I am and
I'm about one millimeter off center so I have to move the stock yet again to get
that distance to halve that distance so slacking off and just move it which
direction did I need to go? check again so I need a little bit extra length on
the stem a half a millimeter and do the same
again and I keep doing this until the two points meet now I'm right on now
this time so let me show you this and let me show you on this face here so I put my
two points my dots in the surface there and then I turn it around until those
two dots are lined up so I just dropped in to them so I've got the exact
distance I want from each side very, very important cinch
everything tight make sure there's no slippage registering the stock against
the face push and on this you can go quite hard I'm going on the edge of my bench I'm
registered here I can put pressure on here my thumb is going on the gauge here this
hand is moving laterally to keep it square against the face and I use my
thumb for that micromanagement of pressure that gets me across the top so
now I have my two lines here on this face I have my two lines so now I just have two more to run on
this face registering all the time against the same registration face just in case I'm slightly off-center out
of square or whatever this gives me the definitive line so all the lines line up
on the corners that's one done here's my mortise hole so I'm going to
set this I know it's already set in between those two lines over end for end
so I'm registering against the same face and run the next two lines and these are
the lines that I want to chop the mortise to in between the crosscut
lines there and there, so this you can start
seeing how this now is going to fit into this mortise hole here and I just need to
remove the waste parts to form the joint so you always cut the mortise hole
first because the mortise hole is very rarely changed inside it's governed by
the exact width of the chisel and inside the hole we don't usually pare inside the
hole so I'm going to my knife and I'm going
to create the extreme wall for the width of the mortise, I'm going here like
this then I'm going to put my piece of wood on here up against the
blade and I'm going on this side make a small nick just to lodge my chisel in
now I'm going to switch hands here you may not be ambidextrous but I'm going to
go into this side you could turn your piece of wood around make your knife wall and that's showing the exact width of the tenon I'm going to make a small nick on
the corner here into my knife nick here slide up to it until it starts to make a
small nick here this is giving me the exact width that I
want for the opposite side slide your knife right into that nick, make a nick
here so this isn't going to be seen there won't be a knife mark seen
particularly strongly on the outside this goes in between can you see here
there's a slight variance here I'll show you in a second between the actual pencil lines because
the knife wall is absolutely definitive so if I roll this here can you see the
pencil line is about a millimeter off which is quite a lot really and the same on
this one half a millimeter here but I do know that this knife wall is exactly
transferred from the other side and that I'm exactly on course now so here into the vise I'm chopping in
the vise you can chop on the bench top if you want to I like the vise it's a good
heavy vise very solid so I don't go into the
knife wall I go about one-eighth of an inch away
bevel in the direction I'm traveling and I chop and then I move over another
eighth of an inch right in between the gauge lines and I chop and then I chop
one more time like this those can't be flicked out they're not
deep enough I go about that back to that first chop that I made
there and I chop down here back into here and just lever out the bulk of
the waste, now my knife wall is very much exposed and I can go into my knife wall
gently here then I move away about two millimeters and chop hard so I've chopped
hard because I don't want to move that knife wall and this has created a space
for my knife to my chisel cut all the way down into the mortise hole that didn't move it but it stayed
right on course so now I lever and I keep levering after a chop, chop vertical and
just lever so this is ever deepening now because
each one of these chopped cuts goes down past the previous one by about one
eighth of an inch my chisel cut is perpendicular the bevel
is sliding the chisel over so inside the cut I have a 30 degree angle because
watch what happens it moves over in the cut you I'm vertical here can you see
I'm vertical here if I take this out and show you inside the cut you can see the
slope of the mortise here right along that inside very important you see that
because you'll see that that's commensurate to the bevel of the chisel
and that act of chopping that way is moving the fibre out of the way the
whole time so now I can lever the waste right
out of the hole and we can see how much deeper we're going with each cut I'm going
through one and three-quarter inches of material here you can see me sloping the
chisel slightly to compensate there like that it doesn't matter
you're going to do that you'll be feeling that when you start chopping I'm two millimeters away from my line
so now I don't to lever on this outside edge because I'll bruise that wall
so I come in here I've turned my chisel around so the
bevel is now on this side so I chop and I get more and more vertical now I'm
going right into the knifewall here and I'm chopping, I'm vertical so now I'm down in that, how to deeper my
down in this cut I am seven eighths of an inch which is
about 23 millimeters so quite a long way in from where I started so I have a slope
down inside this cut now so we'll show you just clean out a little bit of the
waste so we sloped in the cut as we went down so that may seem a little negative
you may think oh I didn't really want that but watch what happens now I go
with the vertical bevel about a third of the way along and I chop at this angle
and that chop takes it straight down I lever in the bottom I lever, I'm moving along about
one-eighth of an inch again just like I was before just flick out the waste these are nice, let me show you what we got, I can't lever against this outside face so here my bevel is vertical, and right
in on the last cut is a vertical, a perpendicular cut that actually takes me
down to a very comparable distance seven eighths of an inch again 22, 23
millimeters very close take a smaller chisel just a 3/8 in here lift out the excess waste from here and
here you can see inside here now nice crisp clean depth 7/8 is exactly half
way of half of one and three-quarter inches and now when I chop from this
side I'm already halfway through exactly the same from this side about one-eighth
of an inch away chop, move another eighth, chop and lever
just a little bit flick of the wrist like this and then
when you feel like you've gone enough go back I'm gonna turn my chisel around a
little bit here that last one halves the distance a little
bit nearer to the line so I don't move the knifewall, the knifewall will stay
exactly where I want it to be, which is exactly the
opposite to the other side start levering out the waste, make space
then for your bevel of the chisel if you look at these they're very, very
uniform these pieces I've chopped out they're very, very uniform notice I don't clean up the walls
because I want the width of my chisel to govern the width of the opening I'm listening now because I must be
closing in on moving all the way through to the other side turn my chisel around there I could hear it went through then so I
know Listen. So I'm through, I pull the waste away
from the shoulder line so I don't bruise that outside rim ever, pull it halfway
along maybe a little less see that sounds too much to me but I move nearer
to the breakthrough point, bevel is now vertical last bit I just turn my chisel around go right
on the knife wall and chop cleanly this doesn't look clean inside you can see
the fuzzy bits on the wall, can you see inside and that's going to hang up the
tenon, I usually just go in with the same chisel I was chopping with, just
pull it across like this that will usually clean off the walls all the way
through from one side to the other That's it, and that's given me a clean inside of the
mortise hole like that it's great this is the mortises cut I may have to trim a little bit after
I'm not sure yet so now I'm going to make the tenon
usually I cut my shoulder lines for my tenon first not the wall so I'm going to take this piece of wood, offer this here
flush it on the outside here to the lowest point so if the end
is actually, in this case it's slightly out of square, so I'm going to go to the
bottom of that out of square aspect I'm going to make a shoulder line across
here now this is an internal shoulder line so
you can make this shoulder line all the way around because with it being
the internal corner it's not going to be seen I work a lot I spend a lot of time preparing my wood
to make sure everything is perfect the reason I do is because I want this
corner here I want these to line up perfectly if
they don't line up perfectly something is going to be wrong so I've got those
cut this line not quite far enough along here and now I'm
going to cut my shoulders with the tenon saw but I'm going to delineate
these shoulder lines again, every time you make a cross grain cut it always
starts with a knife cut then you go to your tenon saw, put my finger right up
against the shoulder and the saw plates and run my finger, run the saw plate
along my finger or my thumb just until I've penetrated deeply enough
for the kerf to guide itself and then I work to my work vertical wall I don't want to go past here, can you see
my saw cut stopped dead on the gauge line I don't want to cut into this face cutting into this face and this face
would be quite negative for me because it's making the tenon strength slightly
understrength traditionally this would always be sawn the cheek of the tenon would have always been sawn and that's what we're
going to do here go across the top I'm cutting on the waste side of my line
this is the bit that we're removing here so I'm cutting on that side of the gauge
line the point on the gauge line I so in other words my tenon is likely to be slightly
fat I go across the top and then I start
dropping my hand down the gauge line you can go from both sides just to help
your saw same on this one go off the top get it good and square then
start dropping your hand gradually with each stroke down this face
so we've basically gone corner to corner reorient either your work or your body, down
this face here so we're following the line I squeeze this against the plate to
keep it nice and tight now there maybe I'm close there, on this face
here usually on these shoulders it's going to
be slightly fuzzy right in here so usually what we do is we go in with a
chisel, wide chisel and just pare this face to get rid of any undulation from
the saw kerf as we prepare the shoulder so I'm gonna do this one here then I'll
show you from this face this is not the usual way but it's so
you can see what I'm actually doing so I go in here just pare these shoulders
just a hair to get rid of any surface fibers now I'm hoping this tenon is slightly
fat because if it is I'm doing exactly what I should be doing so here is too
wide is too thick to go in the mortise hole what I'm going to do I could
either pare this down with a chisel this way like this I can pare across the grain
like this looking at my gauge line the whole time to make sure I'm not going too
deep so just flick that out of the way I've taken off a hair of this side that one is done does this help my
mortise yet it's probably very close but I'm going to show you another method
that I use a lot and that is this router here I set this depth here registering against this flat surface
here till it's just barely kissing the surface I don't want to take anything
off at this stage cinch it tight keeping this down flat against the
surface, I'm taking nothing off and then I turn it in half a turn and then
another half a turn or quarter turn now it's biting I don't take too much off keeping this
right hand, my right hand hard down this guarantees it this surface is
parallel, parallel to this surface perfectly parallel going here let's see
what we got so this is still tight which is what I want so now I'm going to
do the same with the setting that I have on this I'm going to do the same on here
now that's quite a chunk I don't know maybe not no I thought it
was more than that so I'm actually parallel from both
sides I'm going to turn this just a little bit so this is a very useful tool and a very
useful application for a tool it's never been designed for this it's not its purpose but it functions so nicely so here I go carefully I can't really break out on that surface
this time because the leverage is too much so I turn around and come from the
opposite side like this. That probably is going to get me very close to fit, this
goes this way so now we're actually going into the
mortise it's very close now so I'm good for width, yes that's great so I think
that's still too tight but it's very very close I'm going to set this on here slack in a stop off and turn it is just
a fraction of a turn and that is about a thousand I think close to about a
thousand of an inch hard to really measure that gets me very close yeah it's great I want it to be even, now
I know this is not going to be too much now let's see what we've got looks good I'm gonna go in the vise like this and
I'm going to start pressing here and the reason I'm doing this is I want this
kind of contact with my material I want to check here check this side
looks good looks like everything is aligning so I'm applying pressure and
I'm trying to feel inside this mortise hole for the kind of pressure see what point
it's pivoting at it seems to be pivoting like somewhere like here no it's actually in the middle so it's
just a little tight but not too tight so I keep applying pressure listening
feeling until and down on that shoulder that's my mortise and tenon joint
shoulders look good the tenon is just barely protruding
through then I would probably just take a shaving off here just to flush it with the outside of the surface remember it was slightly out of square I'm actually planing against the grain
there so turn around and this joint now would be ready for assembling and
normally it would get wedged at this stage glued and wedged or a drawbore
pin that's my mortise and tenon joint the
shoulders are this one is really good this one is good
too just needs a little extra help and that's got the shoulder perfectly tight a
mortise and tenon joint.
Now THIS is a guy that knows his tools.
His dovetail video is even more impressive [link]. If you're not into woodworking you might not appreciate how precise his sawing is. It helps that he's ambidextrous.