Sunday, July 20, 2014

Four-Stroke Mortise And Tenon

The tools and materials required: clockwise from left, two pieces of 2" wide pine stock perfectly squared around, mortising gauge, mallet, marking knife, crosscut and rip backsaws, pair of bench hooks, paring chisel, primary mortising chisel, narrow mortising chisel, chisel-pointed pencil, and square.

In Four-Stroke Tenoning Exercise, I said that the method could be applied to mortises as well. Here it is, in obsessive detail.

That post has most of the backstory (go back and read it if you haven't already, because that exercise develops many of the skills you need here), but there's some additional background on mortising. The two methods for mortising I'm familiar with are:
  • Chop it out with a chisel (bench or mortise chisel of various styles).
  • Drill the bulk of the waste out, then pare to the lines.
I generally prefer to chop it with a chisel, for no reason other than personal preference. But just as expecting a tenon to fit right off the saw is challenging for a beginner, so is getting a good mortise right off the chisel.

The main difficulty I've observed is keeping the chisel straight vertically when pounding on it with a mallet, and keeping it from twisting. It doesn't take much error at all to end up with a meandering mortise edge down its length, with various bulges and hollows in its walls.

What should be flat planar walls end up pretty bumpy. This makes it difficult to get a snug fit, and imparts twist or misalignment to the tenon when inserted.

The advice I'm familiar with is never to attempt to improve a mortise other than cleaning up obvious protrusions, because pretty much anything you do will end up widening it. Then the tenon that was gauged to the same chisel width as the mortise will be too loose.

As I was working out the four-stroke exercise, I had an epiphany. Why not combine the expected paring of the drilled mortise with the chiseled method? Plan on paring, and adjust the tenon width beforehand with that expectation.

I can hear the howls of outrage now! That's not the way you should do it! That's just wrong! But bear with me here. You can apply the four-stroke method to the mortise walls and get the same quality results it gives with the tenon. You just need to coordinate the two.

The other good news is that every step here improves your skill with saw and chisel, and you are practicing the traditional straight-from-the-saw tenon and straight-from-the-chisel mortise even as you add the paring steps. Eventually you may decide to eliminate the paring because your saw and chisel skills have eliminated the need for them.

I also wouldn't be surprised to learn that this is a common method somewhere. People have been doing this for centuries, so I'm probably not the first person to come up with this bright idea.


Mortise and tenon joints are commonly used to join the corners of frames, such as for frame-and-panel doors. The crosspieces are the rails, and the uprights are the stiles. The typical configuration is that the tenons are made in the rails, and the mortises are made in the stiles. That's how I'll refer to the parts here.

Mortise Layout

Make sure the stock you're working with is perfectly square around. The ends need to be reasonably square, but not perfect. Mark reference face and edge on each. You will work both rail and stile pieces with face sides up. That's how you know if you have one of the pieces upside down. Always check your marks to verify that both reference faces are facing the same way.

Layout the width of the rail (the tenon piece) on the end of the stile (the mortise piece). Leave about a half-inch of extra length on the stile. This is called the horn; it provides extra wood to maintain strength to avoid splitting or blowing out the end grain when chopping the mortise. You saw it off and plane it flush after the joint is glued up.

Mark the length of the mortise in between the rail width marks, about 1/8" to 1/4" in.

Stile (mortise piece) on the left, rail (tenon piece) on the right. The face side is up on both pieces. The edge of the stile is marked for the rail width and mortise length inside that width. The mark corresponding to the right edge of the rail is about a half inch down, leaving a temporary horn for strength. The mortise ends are marked inside the rail edge lines.

The trick to all this is in the setting of the mortise gauge. This is a marking gauge with two pins that can be adjusted for width. Normally you set the width of the pins by setting your mortise chisel on them and adjusting them so that their tips are the width of the chisel.

Instead, drop the chisel between them so that the their sides are the width of the chisel. This offsets the tips, which do the actual marking, by about 1/32". That's it. You've just compensated for the paring you plan to do.

If you have a different type of mortise gauge, one with wheels or knives, you simply have to set the extra gauge width by hand.

The only consequence of this is that it affects the size of chisel you use. The width of a mortise should be between 1/3  and 1/2 the thickness of the stock. Less than 1/3, and you'll have beefy mortise walls but the tenon will be weak. More than 1/2, and tenon will be beefy but the mortise walls will be weak.

You still need to follow these guidelines, but now you have an extra 1/16" of width to factor in. So your 1/4" chisel that was a perfect third of 3/4" stock will no longer produce a mortise exactly 1/3 the thickness. However, it's still within the 1/2 requirement.

The problem is if you were planning on using a 3/8" chisel; that plus the extra width would be too much.

Conversely, if you need the mortise to be a specific width, such as a 1/4" mortise that matches up with a 1/4" groove to accept the panel in a frame-and-panel door, you'll need to use a narrower primary mortise chisel.

Set the pins of the mortise gauge to the width of the chisel. Here I'm using a 1/4" mortise chisel.

Closeup: that means drop the chisel all the way down between them.

Adjust the body of the gauge until the pins are reasonably centered on the thickness of the stile when referenced from the face side. Everything here is referenced from the face side, on both rail and stile, so double check that every time you apply the gauge to a piece.

That way, if the mortise is slightly offset from center, the tenon will be correspondingly offset; but if you turn one or the other upside down, the offset will be on the wrong side.

Press the face of the gauge against the face side of the stile, tip it so the pins trail, and mark the mortise width between the end marks. Mark using repeated light passes; too heavy a pass tends to get caught in the grain. Run the chisel point of the pencil down the lines to make them more visible.

Trail the pins as you push the gauge between the end marks. You can also do it the opposite way, tip the gauge toward you and pull it from the far mark. But keep the body firmly pressed against the face side of the stile.

The darkened gauge lines.

You can mark the tenon now, but I'm going to save it for later once we know the actual depth of the mortise. So keep the gauge around, don't lose its setting. But you can certainly layout the tenon for a specific mortise depth, and make sure the mortise is that depth. I'm not paying a whole of attention to absolute numerical measurements here.

Chopping The Mortise

Other than the extra width, this mortise follows the traditional pattern. Specifically, I'm following Paul Sellers' chopping method. Most other authors describe a similar method, but with some variation in the fine details (or annoyingly, they omit the fine details!).

Note that I'm doing a blind mortise here, the simplest type, not a through mortise. But a through mortise is essentially two blind mortises started from opposite sides that meet in the middle. That requires more formal layout of the mortise ends, since they need to be transferred around the piece from the first side to the second to ensure alignment.

Start the mortise chisel about 1/16" to 1/8" from one end of the mortise, holding it dead vertical, centered between the gauge lines. The key thing is to have the bevel facing away from that end, facing the direction of travel down the length of the mortise.

I like to stand at the end and sight down the length of the stile so I can watch the chisel alignment side to side and make sure it stays vertical. The angle forward and back is less critical at this stage. I start the chisel at the near end of the mortise, with the bevel facing the far end.

Standing at the end of the stile and sighting down the chisel from the back side to maintain alignment as I strike with the mallet.

Make the first cut with the chisel very lightly, about 1/16" deep. Then advance the chisel about 1/8" and drive it a little deeper with the mallet. For each step forward, you can drive the chisel deeper, to that same depth; by the time you've progressed 1" down the length of the mortise, the chisel should be going in about 1" deep.

You'll notice that the wedging action of the bevel on the forward side pushes the chisel back into the previously cut wood, starting to break it out. Meanwhile the end grain wood ahead of the chisel will by cut at the bevel angle.

Lever the chisel forward as you go to pry out the waste. Proceed this way progressively deeper until you reach 1/16" from the far end. Pay attention to the total depth so you don't go too deep.

Start the chisel 1/16" from the near end, bevel facing the far end. With the chisel standing vertically, sight down chisel and stile from behind so that it is aligned with the gauge lines and edges of the stile.

Closeup of the chisel centered between the gauge lines and visually aligned with them as it stands vertically.

After two steps forward down the length of the mortise, levering the chisel forward to pry out the waste and flick it aside. Removing as much waste as you can while you go makes it easier to clean out.

Getting pretty deep! Now the chisel is sliding down the far slope along its bevel a significant distance as it cuts.

Last chop at the far end, about 1/16" from the line. I got a little too close with this one.

The chisel slides down backwards on its bevel, leaving a sloped end.

At this point, the mortise will be an inverted triangle in the wood, stepped in increments on the near slope, and cut smoothly on the far slope.

This is where the narrow mortise chisel comes in. Push it down the near slope bevel up, cutting down the steps. Its narrower width allows it to fit in easily, and its narrow edge concentrates the cutting force. Clean out as much loose waste as you can; it tends to get packed in.

Push the narrow chisel down the slope bevel up to clear it out.

Inside the mortise, with smooth far slope and choppy near slope.

To finish off the mortise, come backward from the far end. Start by angling the chisel back at the bevel angle, so the bevel rides straight down as you strike the handle with the mallet.

From there, simply spin the chisel around, so the bevel faces the near end, and chop the return path the same way as the outgoing path. Because there's little or no wood behind the chisel now to resist it, you'll notice it slides backward and deep quickly. Clean it out again with the narrow chisel.

If necessary, make another series of cuts to go deeper. The narrow chisel is useful for this as well, since the primary chisel can get jammed up along the walls as the mortise gets deeper. You can use the tip to perforate the floor and break up the fibers, then scrape it back and forth.

At the far end, angle the chisel back at the bevel angle, so the bevel is perpendicular to the wood, and chop down. The bevel will ride straight down.

Cleaning out the deep junk with the narrow chisel.

Now finish off each end. Set the primary mortise chisel on the end line, bevel facing into the mortise. Make sure it is dead vertical both side to side and forward and back. Look along both axes to verify. Once you're sure, chop straight down. It should be easy because there's very little wood to remove. Clean this last bit of waste out.

Chop dead straight down the near end with the bevel facing into the mortise. Then spin the chisel around and repeat at the far end.

At this point you have a traditionally chopped mortise. If you're getting a good mortise with straight edges and flat walls, maybe you don't need to use the paring method. Otherwise, this makes good practice. You'll find your initial mortises will get better and better over time.

The chopped mortise, ready for paring.

Paring The Mortise

This is where we really deviate from the norm. This is what you would do if you had drilled out the waste with a series of holes instead of chopping it.

As with the four-stroke exercise, the gauge lines form a recess to drop your chisel into, precisely positioned. That's how that method applies here.

You need to have a razor sharp paring chisel, and pare straight down the mortise walls. It should be easy to pare across the grain because there's only a thin layer.

Set the edge of the paring chisel into the center of the gauge line.

Sight down the chisel and along its side to make sure it's perfectly vertical.

Closeup showing the grip, pinching the chisel to the wall with finger and thumb as you push down.

Move over and make the next slice down, then do the other end. Repeat as necessary depending on the chisel width.

Spin the chisel around to the opposite wall, again pinching wood and chisel together as you push down.

Final stroke. Ok, I think the "four" stroke count has gone astray, but you get the idea.

To finish the mortise, chop down the parings in all four corners with the primary mortise chisel and clean them out. This chisel fits easily now, since the mortise is wider.

Chop straight down in each corner to sever the parings at the end of the mortise.

Setting up to chop down at the other end.

The primary mortise chisel fits into the widened mortise easily now for clean out. That's nice because getting the last bits of junk out is always a nuisance. Turn it upside down and scrape it clean with the chisel.

The cleaned out mortise and severed parings.

To check the side walls, drop the edge of the paring chisel into the bottom of the mortise with the back flat up against the far wall. Sight down the side to see if it stands up perfectly vertically. Spin the chisel around and check the other side the same way.

If the chisel isn't standing vertically, the wall is sloping. If it's sloping inward (narrowing at the bottom), you can carefully pare down a bit in the bottom portion of the side to get it vertical. Just don't remove too much!

If it's sloping outward (widening at the bottom), you're in trouble. You can pare the upper parts of the wall, which means you'll need to make the tenon wider...and now you're down the whole problem path we were trying to avoid. So err on the side of walls that slope inward.

Set the edge of the chisel in the bottom where it meets the far wall and push the back up against the wall. The chisel should be vertical.

Spin the chisel around and check the near wall.

I found just a bit of inward slope in the bottom of the mortise on one side, so I pared that down and cleaned it out.

The final mortise, ready to accept the tenon.

Continue to part 2, where we'll use the four-stroke method to precisely form the tenon.

Saturday, July 19, 2014

Four-Stroke Tenoning Exercise

I did this exercise on pine, walnut, African mahogany, cherry, and oak. The African mahogany was the fussiest due to reversing grain (which is different from South American Mahogany, right Shannon?).

No, this isn't the suck-squeeze-bang-blow of a four-stroke engine. This is more like four strokes of a pool cue.

I've run into three schools of thought on how to make tenons (this also applies to lap joints):
  • Should fit right off the saw.
  • Get it as close as you can with the saw and pare or plane to adjust.
  • Deliberately saw it fat by 1/16" and pare to the line with a chisel.
While the first is certainly the fastest, it requires a lot of practice to get there, so isn't suitable for a novice.

The second is much more common, since it can be done no matter what your skill level. This is how I started out. The problem is that the adjustment stage can be extremely time consuming. It also quickly leads to a losing battle of correction and over-correction until a good fit is no longer achievable.

The third method is what I've come round to. With only a little practice it can be fast and efficient. Looking back through various books, I see it mentioned in passing in one or two sentences. There wasn't enough detail to follow it in a practical manner.

Phil Lowe's article on chisel techniques in the October, 2011 issue of Fine Woodworking put me on the right track. I followed this making the tenons for my Queen Anne foot stool project and was happy with the results.

What really made me a believer was actually watching Phil do it during his SAPFM Seymour night stand demonstrations. He was fast and efficient, and his joints fit together beautifully. Yes, his 40 years of experience had something to do with that, but it was a convincing demonstration of the technique.

Specifically, after marking shoulders and cheeks with marking knife and marking gauge, Phil saws both shoulders and cheeks fat by 1/16", then pares them each down exactly to his lines with a chisel. So the sawing is coarser work, while the paring is very fine, precise work. Breaking it up into these two stages makes it fast and efficient.

I've begun incorporating this method when teaching others how to cut tenons. The problem I've found is that most people have difficulty handling the chisel properly. It's just a very unfamiliar implement, with no analog in daily life.

I've developed this exercise to address that. It's significantly improved my own tenoning skills and will give you new respect for the mighty mighty chisel.

The Exercise

Here I'm going to focus in excruciating detail on just the tenon of a full mortise and tenon joint; as with the sawing exercise for dovetails, we'll concentrate on just a single aspect of the joinery. Mortising is largely a separate skill, but the good news is that a variation of this technique applies.

The type of chisel required here is a paring chisel, in the range of 1/2" to 3/4" wide. These are harder to find than standard bench chisels, but there are several modern brands available. Paring chisels are used for lighter, finer work using hand pressure or only light taps of the mallet. Consequently they are thinner, sometimes even a little flexible, with a lighter tang and handle.

Most importantly, they are sharpened to a lower cutting angle: somewhere in the range of 20 to 25 degrees, as opposed to the typical 30 degrees for bench chisels. This allows a finer edge, but it's more delicate, so can't take heavy pounding. Naturally, this needs to be razor sharp.

Don't have a paring chisel? You can reshape a bench chisel to the finer angle. The metal in cheap, lower-quality bench chisels may require more frequent sharpening when used this way.

Spoiler alert: this method helps for mortises as well! My pile of practice joints in a taste of things to come.

In this exercise you'll work on just two surfaces, one cheek and one shoulder of a tenon. You'll work these repeatedly on a practice piece. Then cut the last bit off, flip the piece over, and repeat the process, now on the opposite cheek and shoulder.

Why flip the piece over? For the typical flat-sawn stock, if you look at the end grain, you'll see that the growth rings are convex with respect to one face, and concave with respect to the other. These show you the bark side and heart side of the board, respectively.

The rings visible in freshly-shot end grain. They're concave with respect to the left face, and convex with respect to the right face, making that the bark side of the tree.

When you pare with a chisel across these rings, the convex or concave orientation affects how the wood responds. This can cause the chisel to dive down into the grain and cut too deep at some points, or blow out the grain at the far end of the cut. Flipping the piece over and practicing on first one grain orientation and then the other helps you learn how to control each situation.

Use a length of pine about 2" wide. I know some people grumble that anyone can look good working pine, but I would say that's not true. Beginners should start with a wood that's not going to fight them so much, then move on to more challenging woods once they have some skills down.

Draw a line down one face of the piece just to mark your starting side. When you flip the piece to repeat with the other side, work on the side without the line. Alternate this way over a few practice sessions until you've used up the whole piece.

Every step here is critical, so concentrate on doing each one well. This exercise is fairly quick, allowing a high cycle rate. In half an hour, you can do it 3 or 4 times. That fast repetition helps you develop skill not only with the chisel, but also with the marking knife, marking gauge, and saw.

The tools and materials required, from top left: square, marking knife, crosscut backsaw, freshly sharpened paring chisel, marking gauge, pencil, bench hooks, and length of pine about 2" wide.


You need a sharp pencil point and sharp marking gauge pin. Marking consists of knifing a shoulder line across the face of the piece, then scribing a line along the sides and across the end grain with the marking gauge. Then darken the scribe line with the pencil so it's clearly visible.

The knife line serves two purposes. First, it cuts the outer layers of wood precisely for a clean, straight shoulder. Second, it creates a recess to set the edge of the chisel into, registering it precisely.

Similarly, the scribe line along each side provides a recess to drop the edge of the chisel into. Along the end grain, it serves as a visual reference for lining up and guiding the chisel.

Scribble two sides of the pencil tip on a scrap to form a chisel point that will fit in the marking gauge line.

Sharpen the marking gauge pin to produce a finer line and reduce dragging. Here I'm using a medium diamond stick.

Scribe a shoulder line across the face of the piece against the square. Use light pressure and repeated strokes to get a clean line about 1/32" deep.

The marking gauge is another one of those tools that people struggle with, because it's just a very unfamiliar implement. To use it, come in from each corner, don't run it off the corner. This ensures better contact of the gauge face to keep it registered properly.

Use firm pressure to press the face against the wood as you move it. Use light pressure on the pin, rolling the gauge so that the pin trails lightly along the wood. Don't try to mark a deep line at once. Use repeated passes to deepen it.

Often the grain will catch the pin and try to pull the gauge off track. The light pin pressure and firm face pressure help to counteract that; you can also tip the gauge the other way and move it in the opposite direction along the grain.

Set the gauge so it will mark a line about 1/16" or so from the face when referenced off the back of the piece. This 1/16" is the thickness of the material that you'll be paring off; it represents the last 1/16" of the tenon cheek to be removed when you're making a real tenon.

On the end grain, scribe up from the lower corner... 

...and down from the upper corner. One the side, scribe back from the end corner.

Fit the chisel edge of the pencil in the scribe line and mark the sides and end.


This is the simplest step. Saw a rough shoulder line about 1/16" away from the knifed line in the waste. I say rough because this saw line doesn't need to be precise or fine. Just don't saw any deeper than the gauge line.

Crosscut a line to the depth of the scribed line. Use the tip of your thumb to guide the saw to the right position.

The resulting cut, 1/16" away from the knife line in the waste.

Cheek Paring

Now we come to the four strokes. Does it have to be exactly four? No, you may find some pieces take 6 or 8 because of the thickness, the grain characteristics, or the hardness of the wood. You may find some pieces are so easy to deal with they just need 2.

But the first two strokes are not precise. They allow you to thin down the paring and observe how the grain is behaving. The final two strokes are where you commit to your most careful work.

This is where the pool cue analogy comes in. You want to line up your shot, then take it, smoothly and with control. Or rather, line up your cut, then take it.

If hand pressure isn't sufficient, bump the end of the chisel handle forward with your palm. This should provide just enough impulse to start cutting, yet not enough to completely blow through the cut out the other side. You may need several successive bumps. None of the woods I tried needed more than this.

First stroke: line it up. Note the edge of the chisel is set about halfway through the total thickness to be removed. Sight down the length of the back of the chisel and line it up with the dark scribe line across the end grain.

First stroke: take it! Lean your body into it slightly as you apply hand pressure forward at the handle. Note how the chisel is gripped against the wood by the thumb, and the finger pinches the back of the wood, safely out of the cutting path. This keeps the chisel flat against the wood and applies braking control so that you can stop roughly halfway across.

Second stroke: line it up again at half the thickness, coming in from the other side.

Second stroke: take it! Ideally it should meet up with the first stroke. Pay attention to what the grain does for these two strokes so you know how to deal with it on the final strokes. Again, note the grip of the fingers and thumb holding the chisel flat against the wood.

This is where it all comes together. These last two strokes are where you need to bring all your skill and control to bear. This is a precision step. You'll set the chisel into the scribe lines on the side to place it at exactly the right position, then watch carefully as it splits the end grain scribe line, correcting the steering minutely as you go.

Third stroke: drop the chisel directly into the scribe line to position it exactly, line it up carefully with the end grain scribe line, then commit and take it! You know what to expect after the previous strokes.

Fourth stroke: drop the chisel into the scribe line, and you know the rest.

The resulting cheek face.

Checking And Correcting The Cheek

While you can do the whole job in four good strokes, things don't always go smoothly. The chisel may dive into the cut, or be deflected out. The wood may fracture and tear. Different woods will behave differently.

But hopefully the four strokes will leave a mostly flat surface, with just a few bumps or divots. There's nothing you can do about cuts that have removed too much, so it's better to err on the side of leaving high spots. They can be pared down flat with the rest.

To check the surface, run you fingers or thumb back and forth over it. They're very sensitive and can detect very small variations. To see where the high or low spots are, lay the flat back of your chisel across the face to see if it rocks or is out of parallel (this is like a winding stick).

With the back of the chisel laid across the surface, I can see a small high spot that acts as a pivot. Small as it is, it may affect the fit and alignment of a real tenon in its mortise.

To make the high spots visible, rub your pencil on the chisel back, then lay it across the surface and rub it back and forth.

The evil high spot is revealed! Plus another in the lower right.

Removing these spots is a delicate operation. Any extra material you remove beyond what's necessary will diminish the fit of the tenon.

Should you remove material around low spots to level the whole surface? NO! That's just making the whole tenon thinner and looser in the joint. Just live with the low spots. If you really have to, it is possible to shave the whole thing down, then glue on a new cheek piece and redo it.

To pare off the high spot, angle the chisel so it's taking a skewed cut across the grain, and use your thumb to push it sideways. Meanwhile, thumb and finger pressure keep the chisel firmly registered against the flat of the rest of the surface.

Shoulder Paring

This final step makes the shoulder as precise as the face. Remember that knife line you made in the beginning? This is where you use it.

You'll set the chisel edge in the line and push forward to cut. Because this is end grain, rather than using the full width of the chisel to cut, use just the corner. That concentrates the pressure of the cut on just a small amount of material.

As you progress across the shoulder repeatedly cutting in with the corner, use the remainder of the chisel width to keep it registered flat on the shoulder. Between the dual registration actions of the knife line and the cut portion of the shoulder, you should get a good clean shoulder.

You also know that the very edge of the shoulder is straight and clean, because that was formed by the knife cut. Any deficiencies in your chisel work will be back from this line, hidden in the joint.

Make sure the chisel is cutting straight in, perpendicular to the cheek. If it angles up, the shoulder won't seat all the way in the mortise. Some people like to deliberately undercut the shoulder (chisel angled down just a bit) to avoid this.

If the corner of your chisel starts to dull, use the other corner and work from the other end of the shoulder.

Start paring from one end of the shoulder, using just the corner of the chisel. Set it in the knife line, push in to cut. Repeat this across the entire shoulder.

Halfway across.

Pare across the flat surface to cut the last bit of cruft from the shoulder with the chisel corner.

The completed exercise.


Now repeat the exercise on the same face. Set the marking gauge another 1/16" in closer to the back of the piece and scribe around. Darken it with the pencil. Knife a new shoulder line 1/16" down from the existing shoulder. Saw down the existing shoulder to the depth of the scribe line.

Set the marking gauge 1/16" closer to the back of the piece and scribe registering off the back.

The next cycle knifed, scribed, and sawn.

Repeat the cheek and shoulder paring, then do it all again. And again.

Eventually you'll have extended the length of the tenon so that it's too large for the width of your chisel. To deal with that, make another saw cut across the center of the cheek, and do the four-stroke paring across each section individually.

When making real joints, that's how you make tenons that are longer than your chisel width, just divide the surface up into as many sections as it takes. This of course multiplies the stroke count, but once you get this down each set of strokes is fast.

The cheek face is now too large for the chisel to do it all at once, so I sawed another crosscut to divide it into two sections.

Alternative Hand Positions

Depending on how the wood is behaving and how much control you have, these are some other ways to do the work.

Alternate first stroke, without pinching the chisel flat to the wood.

Similarly with the second stroke, where you can rest your hand more on the workbench.

If the shoulder paring is resisting too much, start in with a skewed cut...

...then pivot the corner into the wood.

One Last Time

OK, I have just enough wood to do this one more time. It's useful to see just how far you can go and explore the limits of the material and the method. Once the pine gets this thin, it starts to flex and even cutting straight across the chisel can dive in and completely through.

Knifed, scribed, and sawn for the last cycle.

The paring chisel can take amazingly fine tiny end grain parings to level out the deep shoulder.

Now cut that piece off, flip the workpiece over, and repeat it all from the other side, with the growth rings oriented the other way.

The precisely-worked practice piece.

It doesn't take long to make great improvements in your chisel control this way. I verified that when I inflicted, um, tried it with one of my students. He had never used a chisel before and was having the same difficulties I saw other people have. Using this method he was able to produce a piece like the one in the photo above.

When applied to real joinery, this method (and a slight variation for mortises) produces slip fit joints to rival tenons cut with dado stack and mortises cut with mortising machines. To see that, continue on to  Four-Stroke Mortise And Tenon.