Cutting Big Mortises

The mortises in the new bench/whatever-it’s-called are pretty big, and I can’t do them like my usual ones, because I don’t have a mortise chisel that large. So I’m using the old “bore holes to get rid of most of the waste and chop down all sides” method.

This got me thinking that there are a few extra things I do for these that might be useful to someone. So let’s go through them. First, when marking out the mortise, I scribe a line along the center of the mortise:

This is useful for the next step, boring out most of the waste with brace, because I know exactly where to put the lead screw of the auger bit:

Notice that I’m using a square to help keep the bit parallel to the long sides of the mortise direction, and a piece of painter’s tape on the bit to mark the depth. I liked these particular mortises a lot more than the ones in the top, because there was plenty of room to spare when boring down. Going a bit beyond your tenon depth with the brace makes it a lot easier to get out the required amount of waste. (And through mortises are cheating.)

Another note on the holes is that I’m staying a bit away from the ends by, say, 5mm or something. This makes it easier to chop the ends later on.

Next it’s time to get most of the waste off the sides. I’m using an old W. Butcher, uhhh, I guess it’s a firmer chisel, for the sole reason that it’s beefy:

You don’t want to go all the way to the side yet, and while you’re doing this, pay attention to the grain on your initial cuts. Because the wall of the mortise is longer than the chisel, the wood will split in the grain direction past the end of the chisel. If it splits in the wrong direction, you could split it out past your marks for the wall of the mortise.

Now that you’ve figured out the grain direction, mark the “low corners” of the mortise. What I mean by this is that the corners where, if you start splitting the grain at that point, the split will extend into the waste part of the mortise.

And of course, here I am, marking an incorrect corner:

In this board, the correct ones are the top left and bottom right. You’ll see this mark “move” later on in this post after I figured out what was going on.

If it’s just a normal, single piece of wood that you’re mortising, these “low” spots should be at opposite corners. Your grain could reverse or do some other horrible thing, though. And the piece above has the mortise spanning two laminated boards, so it’s possible that it wouldn’t follow that rule, either.

In any case, once you’ve got this done and enough of the walls wasted away, you’re ready to work into those “low” corners. Start with cross-grain chopping on the ends, but don’t go quite all the way to the side, and keep some wood left on the ends (remember that I’m ignoring that first erroneous mark here):

Then, when you’re close, chop down the side with a narrow chisel:

Notice how the waste is splintering out to the waste side of the mortise wall. You might need to do a little back-and-forth to get to your line on the side, but it shouldn’t be too bad with a narrow, sharp chisel.

You also might need to be a little cautious if your wood is uneven. This is (southern) yellow pine, and the darker latewood in this stuff can really shove your tools around. Douglas-fir can do that, as well.

When you’re all the way to the bottom of that corner, grab a wider chisel and chop the wall right next to the corner:

Work your way to the other side in this direction. The wood will continue splitting into the waste, as you can see above. When you reach the end, you can square it off like the “low” corner; when chopping the wall over there, it should not split because you can overlap the stuff that you’ve already done; the chisel will slice instead of tearing out at the border of where you already worked if you keep it flush to the wall.

Then you can go all the way to the ends. I don’t have any photos or anything of this; just use the standard practice of working your way back to the ends until you have enough left that you can cleanly chop it without bruising the wood. Though it’s not so relevant here, it really matters on a through mortise.

You’ll probably need to tune the walls a little due to the way that chisels tend to cut. One nice thing about these big mortises is that it’s really easy to stick a square down there to check to see if it’s complete:

Notice how the “low spot” mark on the near wall has migrated from the left to the right in this picture. Sigh.

So maybe this is helpful. I don’t know. Mortising can be time-consuming. I really understand the reason that hollow-chisel mortising machines exist. And I have to admit that they are kind of tempting.

In any case, the joint that I made in this post was the last one for the new auxiliary bench:

It’s ready for glue-up.

Auxiliary Bench: Leg Joints

Now I don’t know if it will be 12 joints or 16. Do twin tenons count as two joints? Something tells me no.

Of course, both of the joints on the front just happened to land on the two areas near the shallow knots on the only board of the top that contains a little bit of resin. Yuck, but I guess the one upside is that most of parts that are a little tacky will be covered by the leg.

Here’s what we’re looking at now:

In the end, the legs will not be this long, but I’ll trim them to length just before glue-up.

Now for the stretchers. 8 joints. For sure this time; I’m not doing any more twin tenons, and if I do double tenons, those probably only count as one.

Recessed Mortise and Tenon

Here’s a quick little note on how I cut the mortise-and-tenon joints for the frames of projects such as the nightstands and the stool (though to be honest, I didn’t really do it this way until the latest project).

Normally, you arrange a mortise-and-tenon joint so that the faces of the two members that you’re joining are flush. However, you can recess the tenon member so that you get more of a three-dimensional look. In part, I’ve done this to frames that hold panels. My panels aren’t typically raised, so getting a little extra depth is nice:

Start by milling your pieces and figure out roughly where the mortise ought to go. You don’t need to be too precise about it; just make sure that your tenon member covers the mortise fully, and try to even out the shoulders as much as makes sense, because tenon shoulders make your joint significantly tougher. You can mark the area with pencil if you like.

Then mark out a line with a marking gauge for one wall of the mortise. If you really want to, you can set a mortise gauge for the width of your chisel and mark both walls, but I don’t do that because I set my mortise gauge from the mortise itself after I’m done chopping one.

Chop your mortise. The following photo shows a completed mortise, and the tenon member roughly at the depth it will eventually go:

Set your mortise gauge if you haven’t already. Set it from the mortise piece, as if you were going to chop another mortise:

Now, figure out how much of a recess you want. Set another marking gauge to this depth. Mill a thin, flat piece of wood to this depth by marking the piece all around with the gauge, sawing, and planing to the line (normal practice for milling wood if you do it by hand; feel free to use an electrobeast if you like).

This piece of wood will be your spacer, and is really the whole trick to putting the tenon in the correct place.

Mark out your tenon the usual way with your mortise gauge, but put the spacer between the stock and the tenon member as you’re marking. Mark from the face side.

Now, saw your tenon (the following photo is gratuitous, but just in case anyone’s forgotten how to saw a tenon cheek):

And you’re done.

The point to making the spacer is that once you have it made, you can use it over and over. I had to make dozens of these joints for the new project but needed only set the mortise gauge once. I just used it with the spacer for all of the joints I needed. (Obviously, you don’t use the spacer when marking the mortise; only the tenon.)

Nightstand: Decoration

One of the design specifications for the nightstand project was that it had to have “something curved.” After some grumbling about this, I decided to take it as an invitation to steal something I saw in one of Krenov’s books.

The first step was to resaw the wood for the piece. The target board was only 3.5″ wide and was a real piece of cake with the frame saw:

After getting this four-square, I headed back to the drawing board and squeezed out a full-scale drawing of the decoration piece. Unfortunately, I don’t have a big enough printer, so to make the template, I had to tape two pieces together using a light box from my old slide photography days and some mysterious hands:

In retrospect, this was a silly way to do it. I should have found someone who had a printer that can do legal size. (Strangely enough, I just ordered one, but not for this kind of thing.)

Next, I taped the frankentemplate to the board and traced the pattern:

Before anything else, I now had to address the way that the decoration was to be joined to the frame. Basically, this is a twin mortise-and-tenon, and the layout promised to be a pain. To mark the mortise offset into the frame piece, I did this:

  1. Test-fit the closest frame stretcher in its mortise.
  2. Lined up a piece of scrap flush with this stretcher’s front.
  3. Centered my mortise chisel alongside this piece.
  4. Made a mark with the chisel in the frame at this offset.
  5. Used a marking gauge to make a line for where to chop the mortises.

That sounds a little complicated, but it’s not. It was a lot easier than chopping the mortises themselves, because the mortises are so tiny that you have to be really careful prying out the waste, or you’ll dent up everything and have awful marks on the frame. Nonetheless, the task is complete soon enough:

Then, on to the tenons, which were also oh-so-much-fun to lay out. It’s a little easier, though:

  1. Using the same stretcher test-fit, measure the distance between the depths of the front of the stretcher and the start of the mortises that you just cut.
  2. Set a (different) marking gauge to this distance and scribe it on a piece of scrap.
  3. Chop a mortise along the scribe line in the scrap (with the same chisel that you used for your original mortises, obviously).
  4. Set your mortise gauge according to the mortise in the scrap.

Hey, that wasn’t so bad, was it? The only real grumble I have with this right now (and this holds for all mortises) is that my mortise gauge takes too long to set. Because one screw fastens both arms, they touch (through a center plate), so when you’re setting one arm, the other one moves. You have to fiddle with it a lot. Grr, when I get some free time, I’m going to make some gauges and I am going to solve this stupid problem, and probably not by just using a single arm like some of those nice English and Japanese gauges.

The good news is that once you have your gauges set, you don’t have to reset them for the next joint if it’s the same type.

In any case, with the tenon marked, it was time to saw the cheeks and do the usual mortise-and-tenon stuff:

Before long, you have your tenons.

It was then time to cut out the pattern and shape. I did the cutting with my coping saw, and then I evened and squared up the top and bottom with my Shinto saw rasp:

I’ve mentioned before how much I like this tool, but it has its limits, and one of them is that it can’t get into confined spaces so well. To square up the insides, I pared across the grain with a chisel, and then used a knife in the tightest areas:

Then it was time to shape it. I used the old “finger on the side while holding the pencil” trick to outline the rounding depths:

Shaping the top was a matter of a minute or so with the saw rasp. The bottom was also reasonably fast with the Gramercy sawmaker’s rasp, though I would have preferred a larger half-round for that. I did the inside with anything that would fit. The last shaping tool was 80-grit Norton 3X sandpaper, which thankfully fits everywhere, which left me with this:

Then I hand-sanded with 120, 220, then 320 grit to get to the final point, and I test-fit it with the front of the frame:

It looks fine, I suppose, but it took longer to make this than I care to admit. I think I may glue up just the top tenons in the decoration to account for wood movement. This thing isn’t exactly structural.

Nightstand: Frame Joinery Complete

The nightstand project requires 24 mortise-and-tenon joints for the external frame, four for the drawer runner supports, and four more for the decoration on the front. I’ve cut all of these except the ones for the decoration. Here’s a shot of a test-fit of the external frame (without the runners):

My speed improved significantly while making all of these joints. When I started the first one, it was taking me as long as 45 minutes to make one. Most of the time was spent paring off little bits of the tenons, most annoyingly, on the shoulders. By the time I did the drawer runner pieces, I was doing them in under 30 minutes. (Yeah, the pros do them six times faster, but I’m not a pro.) What’s more important to me than speed is accuracy, and that improved tremendously, too. All of my tenons now seem to fit right off the saw. The only paring I need to do is still that little bit on the shoulders, but it’s going faster now. I’m using the mystery chisel for that because a 1.5″ chisel has a lot of registration area. It really seems to be holding its edge well.

I also managed to cut myself with my dovetail saw. Ouch, I didn’t realize it was that sharp.

This project’s joints are a motley bunch. I’m using different offsets at different locations to try to maximize contact based on constraints of panel and corner placement. Some have haunches to improve alignment. Here’s a shot of the middle frame layer, the one that the drawers will rest upon, showing the drawer support runners that I just finished up today:

The runners, back, and right side are depicted in their intended final configuration, and the front and left sides are not attached. When finished, the sides will have rabbets with grooves for where the side panels will rest, and the rear will have a groove for the rear panel.

This is a shot of the current state of the parts and parts-to-be:

The mostly-complete parts (18 of them) are in the front, and the number of pieces in the back indicate that I still have a fair amount of work to do here:

  • join the top
  • join and rabbet the shelf
  • mill the pieces for the drawer and make the drawer
  • mill the panels
  • groove the frame for the panels and shelf
  • make the drawer pull (wood for drawer pull not shown here)
  • glue up everything
  • varnish

What to do next? Well, I’d better pick something. I do have a deadline for this piece. It’ll be either the decoration or joining the shelves, I think.

Nightstand: Joinery Started

Yesterday, I finished milling all of the nightstand pieces except the drawer and panels. Looking back, it looks like it took me two and a half weeks to do all of it. It might have gone a little faster if the wood hadn’t moved so much after resawing. I had to go to another board to get enough consistent material for the top and shelf. The shelf was especially bad; I had originally intended that segment to be the top, but I introduced so much twist into the board when milling that I had to thin it out.

I wonder how much faster this would have gone with a bandsaw. When I think about it, probably not too much, because it would still require planing and more flattening, and if I get faster at that stuff, then that eliminates a big chunk of the time I spent on this. (The resawing, that’s a different story.)

But that’s mostly behind me now, so I arranged the pieces I had into the orientations that I’ll use for the frame layout:

It was a little tricky to get everything oriented so that none of the grain will stick out like a sore thumb. Some of the faces have ray fleck because they’re cut on the radial plane (as if they were from a quartersawn board), and although this pattern looks great in beech, I didn’t want to make it stand out on this piece. In addition, due to the various cuts on the board, the visible ray thicknesses vary slightly from piece to piece, so I matched them up on each side of the nightstand as much as possible.

With that done, I labeled each piece, made a map of the joints, and was able to do the top rear joints today–two little haunched mortise-and-tenon joints!

It’s such a relief to be at this stage now. My worries now are essentially how I should go about cutting these things. I started with the rear top because no one is ever going to see those, so if I mess them up, it’s okay. I guess I’ll finish off the rest of the joints around the top and work my way down to the next level, so that I can mark off the distances from existing joints as I go.

The joints will be a mixed bag of mortise-and-tenon joints. I’m using haunched ones at the top because I want more registration surface and I want to avoid blowing out mortises at the end (I was very careful this time). In the middle and the bottom, there will be more basic mortise-and-tenons, but the tenon lengths will vary. I have this in the drawing, or at least I pretend I do.

Making a map of the joints helps a lot. I had a mental one for the stool project, but because there are three times as many joints in this one, I decided to scribble it down on paper. And what an incredibly professional scribble it is.

You can see how I first drew it in 3D with circles and arrows (and a paragraph on the back of each one, har), but gave up on that and just broke it into top, middle, and bottom levels. I give each joint a number and when I cut a joint, I put the number on each piece. Here, the numbers go counter-clockwise around the frame from top to bottom. At first, I was numbering consecutively when moving from level to level, but then I decided it might be easier to just add ten to the starting number for the previous level and go about it that way. At the very least, it makes it easy to identify the level to which the joint belongs.

Making a Mitered-Face Mortise-and-Tenon Joint

On my visit to Taiwan in December, I had a chance to look at a family cabinet that was probably made in the 20s or 30s on the island. No one could tell me a lot about it, but the thing that fascinated me the most was that it had a joint that I did not recall ever seeing in the wild. Then on the trip to Sanyi, I saw a new cabinet with the same joint. When I got home, I looked for it in my books, but I did not find it. The only thing I saw that was similar was in a book on Japanese construction joinery.

For lack of a better name (or research, at least for the moment), I’m going to call this a mortise-and-tenon joint with a mitered face, because that’s what it is:

The ones I saw have through tenons, as opposed to this one, which does not, but it’s basically all the same idea.

I was really eager to make one when I got back from Taiwan, but I didn’t have the chance because I was too busy making other stuff. But right now, I’m varnishing both the bookshelf and the stool, and I don’t have the next project designed yet, so I thought I’d try some new joints. I made my first one yesterday, but I wasn’t entirely successful, so I tried again today.

The first thing I did was mark out the miters on the mortise and tenon pieces. I accidentally marked a shoulder on the face of the tenon piece here. The shoulder should be marked all the way around except for on the face with the miter. Somehow I will forgive myself for this:

Then I marked the face thickness around the edges of the mortise and tenon pieces (don’t mark on the bottom of the mortise, though). Notice the use of the mini wheel marking gauge that Lee Valley “made” everyone buy last year:

With this done, I set aside the tenon piece and chopped the mortise. A very important note here: For the distance between the inside of the face and the mortise, make sure that it’s at least a little bit bigger than the width of your smallest chisel! My smallest chisel is 1/8″. I made this mistake on my first attempt.

Chopping the mortise was easy as usual with a pigsticker, especially on yellow-poplar. On my first attempt at the joint, I blew out the sides of the mortise, but I managed to avoid that today:

(I felt that it was pretty important to mark the waste sections of the mortise and tenon with an “x,” because the miter makes things a little complicated.)

With the mortise chopped, I set my mortise gauge from the mortise, then set the mortise piece aside and turned to the tenon. After marking the tenon width, I sawed the cheek of the miter, then the inside cheek of the tenon, then finally, the outside (back) cheek of the tenon. I did not saw any shoulders yet.

All three cheek cuts go down to the shoulder line. Again, the shoulder line on the face above is an error. It should appear on the other three sides, but not this one.

Working from the back of the tenon, I sawed the rear shoulder first, then sawed the top of the tenon to the proper height. I continued the tenon-height cut through the waste between the face and the tenon, so I was left with this:

I decided to saw the miter on the tenon next. During my first attempt yesterday, I found it pretty difficult to do freehand, so this time, I clamped a piece of scrap across the knife line and used that as a guide for a crosscut saw:

This worked surprisingly well, and I also used the same technique for the mortise (but I’m not at that point yet).

Next was to finish the tenon. I had to remove all of the waste between the face and the tenon. I did this by first chopping down along the grain, then paring the pieces out (notice the 1/8″ chisel here–remember how I said that the width of your smallest chisel is important?):

I also needed to remove the ends of the tenon to make the length fit the mortise. I used the same technique, but I was also able to make partial sawcuts, which helped a lot.

With the tenon finished, I turned back to the mortise. I first sawed down the cheek of the miter, where the tenon piece’s face fits. I cut only down to the knife line that marked the miter, and then I used the miter-sawing technique above to remove the piece. A little paring and cleanup was necessary with a chisel and my rabbet plane, but this time, it all fit together perfectly:

Yeah, oops about that shoulder line again. The end of the mortise piece sits a little proud of the end. You can plane this off. I suppose that for a full frame, you’d want to cut the pieces with the mortises slightly longer than you need, so that you can measure your overall width from the inside and plane off the excess. Or maybe not, I’m not sure.

It’s unlikely that I will use this joint in a project soon, but it’s nice to have around. But other than the lack of a suitable application, I really should get a smaller mortise chisel if I’m going to be working in thin frames like this. I really pushed the limits of what I was able to do with my W. Butcher 9/32″ chisel. If it were any wider, I would not have been able to fit the mortise and tenon inside the space available with the face and its buffer area factored in. So maybe I’ll be on the hunt for yet another pigsticker now, a 3/16″ or similar. (Sigh.)

Stool: Messing Up and Repairing Mortises (again)

In preparing to attach the stool’s top to the leg frame, I first measured, marked, and cut angled tenons on the tops of the legs. I used the scale drawing again as a guide. Here’s a photo of an angled tenon before I finished cutting the shoulders at the long ends:

That was a fairly simple task, even though I was cutting the tenon before the mortise. To make sure that the tenon fit, I chopped a mortise in a piece of scrap and test-fit.

Then I assembled the frame and double-checked the distance between the tenons, and carefully laid out the lines that I’d chop against on the stool top. Then I broke my mallet chopping the mortises (as described in the preceding post), so I had to wait for the glue to set on the mallet repair until I could get going again. When I did, I was excited to see a test fit.

I was not so excited to discover my latest boneup:

Arrgh. I had chopped the mortises on the wrong side of the lines. I have got to get more careful with this. It’s, what, the third time I’ve done that in two months? I was pretty discouraged, so I took a break while I tried to figure out what I would do about it. Also, I was hungry.

Then I went back to the shop and cut out a piece of beech to the same thickness as the tenons. I inserted this into the mortise, and then extended the mortise (this time in the correct location) by chopping against the side of the inserted section:

After doing this for all four mortises, I had the following:

And then I did a test fit to make sure that I’d actually chopped them in the correct place this time:

Phew. It fits, and there’s only a small void showing on the underside of the stool. But if left and glued up like this, there would probably be a tendency to rack, because the legs could conceptually slide around. Therefore, I had to fill in the originally-cut side of the mortise.

I sliced off a small section of the piece of beech I used to register the chisel when chopping the correct mortise, and glued that on one side where I’d originally chopped the mortise. Then, on the other side, I inserted the section again to “clamp” it in place as the glue dried:

After each mortise got its repair, I did another test fit. Incredibly, it seems to have worked. Now I just have to finish off the edges on the components and glue up.

Stool: Frame Joinery Complete

I managed to get a chunk of shop time in today, and finished the remaining mortise-and-tenon joints in the components that make up the stool’s frame.

After doing all of the angled joints first, I found myself relieved when I got to the normal mortise-and-tenon joints. The tenons aren’t any more difficult to cut on the angled joints, but you do have to pay attention when making the mortises. The normal ones are blissfully mindless, which probably explains how I managed to chop a mortise in the wrong place again. I was able to fudge a way around that error. One of these days, I’m going to learn to be careful where I put those things.

With each of the joints complete, I made a test-fit, and it looks like everything works out pretty well:

The only remaining work to be done here is to cut the top to its final size, and then to attach the top to the legs. That latter part will involve angled tenons, yay.

I have been debating on whether I should chamfer the edges of frame pieces. I was originally planning to, but I kind of like the lines on this thing as it stands now.

Another debate is now if I should make a new mallet or not. The Thagomizer is a great mallet that has worked perfectly for me with the scale of joinery that I’ve been doing so far. However, for the first time, I found myself wishing that maybe I had a little more mass and leverage while chopping the larger mortises in this beech. If I ever do make one, though, it won’t be for a long time. I have too much to do.

Stool: Cutting an Angled Mortise and Tenon Joint

In my last post, I sawed the angle at the bottom of one of the legs of the stool. Now, I felt it was time to try one of the angled mortise-and-tenon joints with which half of the stretchers will be attached to the legs.

I again went back to my scale drawing and marked out where the mortise would go:

Unlike most of the joints I’ve made in the past, I couldn’t use one mortise gauge to mark both the mortise and the tenon. This is because a 1″ wide stretcher will meet a 1.5″ leg, so there has to be about a quarter-inch of space on either side of the stretcher so that it’s centered.

So I had to use a little bit of actual calculated measurement for this. Fans of the metric system may want to skip to the next paragraph. My mortise chisel is 3/8″, and half of that is 3/16″. The leg is 1.5″, or 24/16″, and half of that is 12/16″. That means that to center the mortise, I needed to align the near edge at 9/16″ (12/16″ – 3/16″). (Gee, I guess there was a good reason for not going with the 7/16″ chisel for this project after all.)

I used a marking gauge set at 9/16″ to scribe just one line for the mortise. From that point, it’s just like chopping a regular mortise, except at the ends. This mortise is not rectangular, but rather, a parallelogram. I used my sliding T-bevel to get the approximate angle on both ends while chopping.

The preceding image is actually a bit of a fib, because when I was doing this, my hands were switched (left on the chisel, right on the bevel), because I use the mallet with my right hand. I think you get the idea, though.

Next up was to saw the tenon. For this, I set up the mortise marking gauge. The first thing I did was to chop a mortise dead center in a 1″ width into a piece of scrap. Then I stuck the knives into the mortise and set the gauge:

Notice that this piece of scrap is roughly sawn on the face that you see here and it’s actually a little more than 1″ wide. This doesn’t matter, because the reference face of the scrap is flat, and I scribed a line at 1″ on the top, but I admit that it makes for a confusing picture.

Proceeding to the actual tenon, I went back to my scale drawing and marked out the limits of the tenon shoulder. When I had a mark in place, I used the sliding T-bevel again to mark the shoulder:

After using the mortise gauge set earlier, it looked just like almost any other tenon, except that the shoulder was at an angle. Sawing at angles turned out to be tricker than I thought, but then I remembered another tip from that book I mentioned in my last post; you can put a piece of scrap with one side relieved between the work and whatever you’re holding it against to bring it roughly square. This worked surprisingly well:

And soon, I test-fit my first angled mortise-and-tenon joint:

There’s a little gap in the joint in this photo; the test-fit revealed that I still had a little more trimming to do on the shoulder.

Three more of these plus four non-angled mortise-and-tenon joints to make, and the frame will be together, ready for its joinery to the top.

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