The Fuigo Joinery: Part V, The Finish

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Sometimes I forget to show things that I think are too commonly understood, but the humble shooting board deserves a mention. When I first read of this tool in one of Tom Fidgen’s books it was like a revelation. Seriously, how does one get on in the shop without a shooting board? I’m still using my push style board on top of my planing beam because its already been made, no need to waste this one just to be pulling a plane across the work. And this little low angle block plane with adjustable mouth is exceptionally effective at end grain work. Here I’m trimming the piston head board to length.

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I use the wedge from my shoulder plane as a template whenever I’m cutting mortises that will be wedged. For some reason I felt like laying this out with ink, sometimes the ink is more comfortable because its so easy to see, though a little less accurate than knife lines in theory. In practice the more accurate line to work to is the one that you can actually see clearly. I’ve taken to moving around a small work light just to get things properly lit in the shop on days when the daylight is missing.

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After mortising the piston head board I roughed down the handle to a cylinder and drilled the hole for the piston rod tenon.  The handle has to be made first so that the tenon can be fitted properly at the lathe. I decided to make the hole blind, part of the clean look of the fuigo.

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I struggle to make forms that are not ugly at the lathe. If you asked me what looks good in terms of curve and form I couldn’t tell you. Its much easier to say something is ugly and keep removing wood until it looks good, that’s generally my approach. I may have looked at half a dozen pictures of fuigo with these handles, but you don’t really see the form until you make one for yourself.

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The piston rod, having previously been squared and cut to length, was mounted with a two jaw chuck. When I was drawing the plans for the fuigo, this is one of the design constraints for total length of the box. This lathe may suck but it does have some decent bed length.

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The chuck is holding the wedged tenon end, with the handle end against the tail stock so that its easy to check the tenon fit on the handle without unmounting from the lathe. After roughing down to a cylinder I used my parting tool and caliper to cut down to 1″ diameter along the length of the cylinder.

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The cut that defines the shoulder between the square cross section and the cylinder is a good example of the different quality of cut between the parting chisel and skew chisel. Basically the difference between cross-cut and rip-cut.  The tip of the skew chisel, although it makes me nervous to make this cut, gives a beautiful clean end grain cut without tear out.

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The skew chisel, with hand as steady rest, was also indispensable for smoothing down the cylinder to final dimension. I made a gauge block for the bearing ID so that I could check the piston rod without dismounting from the lathe. The final bit of fit was brought in with 220 grit sandpaper, so that the bearing gauge ran smoothly over the piston rod.

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With the lathe work done I cut the tenon and marked for the wedge that secures the face of the piston head board. I used the tenon cheek cut-off to support the tenon as I mortised.

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Mortise cut, tenon chamfered, looking good.

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I had a little scrap of walnut that was the right width for the 1/2″ wedges, so it makes some nice contrast, though you’ll never see it in use. The piston head board was from flat sawn stock, so it cupped a little. I placed the concave face on the side opposite the wedges, just seemed to make sense like that. Eventually the handle will be drilled for a cross-pin, but I don’t want to do that until the piston is fitted to the fuigo because the handle has to be off to take the rod out of the box. I also shortened the piston rod by 1/2″ from the plans so that it would actually fit in the box. As you can probably imagine, the piston rod and head board have to be wedged after assembly while inside the fuigo.

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I would love to find some kind of fur to use as the gasket material, fur is probably the better material because of its natural slickness and fuzziness. As it is I really want to get this thing working, and I can always replace a thin gasket with a thicker one later. With a pair of calipers I measured this towel to be 1/16″ at full compression, 3/32″ in use. So each side of the piston head board was reduced 3/32″, with the exception of the bottom which I only reduced 1/16″ because the gasket material will compress more under the weight of the head board.

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The fit turned out to be quite good with the clearances I guessed for the gasket material, perhaps a little tight top to bottom, but I’m going to see if that changes with a bit of use once the piston is “run in” a bit. All of the internal wooden surfaces in contact with the piston head received two coats of paste finishing wax to make the action nice and smooth. Even as careful as I was with drilling the piston rod bearing and dimensioning the piston rod I still had a little binding towards the back of the stroke (when the rod is pulled out all the way). I could have adjusted the bearing, but in this case just hand sanded the bearing rod until it ran smoothly along its length. I finished the piston rod with a coat of paste wax as well. The lid is simply held on with a snug fit, I didn’t see the need for fasteners.

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And here it is, ready to breath life to a forge. It feels a bit tight, but I’ll wait to make adjustments until I use it a bit. I still need to pin the handle to the rod, but its tight enough at the moment that I’ll wait. It pushes some serious air! I am deeply satisfied with how this project turned out, I totally disregarded the length of time it took to complete. Now, looking at the finished object, it still amazes me that I have one of these, I almost don’t believe that it works so well.

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If you’re into these fuigo you’ve probably read about the gentle woosh of air, the calming click of the valves. The only thing I can compare it to is the meditative quality of shishi-odoshi used in Japanese gardens.  This bellows is the quality of a professional tool, part of me knows I’ve made something too good for me, I aspire to be worth using it.

Next comes making a charcoal kiln for proper softwood charcoal. And perhaps, if my vision stays clear enough and I can train enough carpenters, a small building to house the forge, like Mark has imagined here.

The Fuigo Joinery: Part IV

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Welcome back! I’m working again on the fuigo, a traditional Japanese wooden bellows.  They’re quite simple in design, but not commonly made by skilled woodworkers here in America, usually by blacksmiths and aspiring swordsmiths, so the joinery element can be a bit undeveloped. Don’t fear the joinery, its a question of durability, not just aesthetics. Its occurred to me more than once during this build how powerful a tool is the hand plane, kanna, that it can handle such large and wide material at such a moderate cost. I’m looking at planer/joiners right now and its not even worth my money to get a joiner smaller than eight inches. Because of my hand planes, I can afford to wait for the right beast of a machine to come my way. Who knows if it ever will?

The photo above is the tuyere bearing block with its hole cut, being used to mark the hole in the birdhouse side. I had meant for the tuyere bearing block to be a bit wider, but there was an error in my plans concerning the internal width of the piston box. I cut both the piston rod bearing block and the tuyere bearing block from the same length of stock, and had to switch them around to have a usable piece of wood after cutting the piston rod bearing block too short.

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If I was being super traditional about every detail I would be nailing these two pieces together. As it is, I find screws to be friendlier to the next person who’ll have to work on this. To keep the outside of the fuigo looking clean and unencumbered by a bunch of screws I hid as much as possible on the inside face.

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The piston rod bearing block was next. I clamped the block in position on the side. Previously I bored a pilot hole in the side where I wanted the piston rod to come through.

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With the proper position maintained by the clamps the side was removed and drilled from the back for screws to attach the bearing block. I also drilled through my piston rod locating hole so that it marked the bearing block.

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Boxwood anyone? This stuff is very dense, one of the better bearing woods after ironwood. I cut myself a small piece to inlay into the bearing block.

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Working on small pieces at the planing board can get difficult because there is not enough room to place your foot directly on the piece. I had to use my heal to hold it against the planing stop. This is probably the widest mortise I’ve ever chopped, full width of my 48mm chisel. I cleaned to depth with my router plane, though it was a little large for the blade to work in such a small space.

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With the mortise cut I used my shooting board to trim the boxwood bearing to a perfect snug fit against the end grain. Hopefully when this bearing shows too much wear, probably after I’m dead, the next guy will be able to pop the old bearing  out without any trouble and source a replacement.

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With the bearing installed I re-mounted the bearing block and centered the whole affair on the drill press table for a 1″ hole with a forstner bit. It is really, really important that you get a good straight hole here, so that the piston rod won’t jam and you maintain as tight a fit about the bearing as possible to minimize air leakage.

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And here it is, the finished bearing, cool! I had considered using a piece of steel pipe, or copper, brass, whatever. Compared to buying a brass bearing the nine dollars I paid for my little chunk of boxwood will make a LOT of different bearings. I’ve used wooden bearings on bobbin winders, spinning wheels, they’re awesome.

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With the bearing blocks finished I took apart most of the fuigo and installed the glass across the bottom and the piston stops. Notice the length of the piece of glass relative to the length of the fuigo. For a while I wondered why you would sacrifice the length of internal displacement and put a shorter length of glass in the fuigo than it could handle. The reason has to do with the piston rod bearing, and the tolerances that you can achieve. Just as with a spinning wheel’s bearings for the wheel, you want your bearing points to be as far apart as possible. By using a shorter length of glass and placing it as far toward the back as possible you insure that the bearing rod is less likely to bind in the fully pulled back position.

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Installed the flapper valves. This thing is starting to look like a proper machine!

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I reassembled the sides and found a stupid error. When I originally installed the birdhouse side to mark the  bevel on its top edge I tapped it in with a block and hammer. What I didn’t realize was that the tapping with a hammer caused the sides to pop up a little bit. Thus the birdhouse side was made too wide. I had to go back and plane it down, definitely an error I’ve learned from about assembling cabinetry. The birdhouse side was just a tight fit, to get it back out I had to tap on the bottom board like backing out a plane iron

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In any case it was an easy mistake to fix, and I soon had the birdhouse top installed with some screws through the face.

I finished the fuigo up yesterday, this post is just getting too long to show it all at once. I don’t have a tuyere pipe yet, I’ll definitely need to shoot some video of this thing breathing life to a fire once I get it set up. Stay tuned!

Oh, Sebastian just posted some drawings by Mark Grable for an Open Source Forge. Really beautiful work Mark, inspiring and at just the right time, thank you.

What happens when woodworkers meet?

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The first meeting of the little Japanese Daiku study group I formed was great! I’m late to writing of it because of the greenhouse, almost finished, so close.  That and every once in a while its healthy to take a break from the computer and let your vision drift to the far away.

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Thanks to Peter and Eric who were in attendance we had a lot to discuss, starting with Peter’s excellent set of sharpening stones. Unfortunately I can’t remember the names, perhaps naniwa for the colored ones? They were softer than my Shapton ceramic/glass, and very fast. With the addition of a nagura stone the slurry gave a beautiful polish for the grit range.

This is a great example of how woodworkers immediately benefit from getting together. No woodworker can afford to buy a bunch of same grit stones to compare, so naturally the sharpening stones are the first thing of interest when woodworkers meet, regardless of place or time.

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Eric brought an excellent set of honing films, which cut more slowly than the water stones/ but left a very bright clean polish. If you’re looking at what to get for sharpening, something between the cheapness of sandpaper and the healthy expense of a set of natural stones, it is honing film. Works great, seems to be holding up okay for Eric, and is available in a nice range of grits and very moderate costs.

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The beauty of the day? A large natural stone, comparable to 1000/3000 grit range. Didn’t work on it too much because it didn’t have enough soak time when we first started. It felt very coarse in use, but the polish had character, very nice stone!

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Somehow aviator sunglasses and sharpening stones look cool together, notice the concentrated but relaxed look on Peter’s face, perfect attitude for sharpening.

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As part of re-organizing the shop to make room for more people I put together this bench set-up. I locked my trestles together with a diagonal brace on either side, the beams are 4×6 screwed to the trestle  with a couple smaller boards thrown across the middle to put tools on. Pretty solid in use too. The 4x6x8′ are about $16 dollars a piece, something like that, so this is a very affordable setup, and easy to keep the beams flat. I was a little worried that having two people pounding on it at the same time may make it difficult to work, but it really wasn’t a problem. Haha, Sebastian advised me not to make it too nice, hopefully this is okay.

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Peter had to take off after the sharpening stone shoot-out to prepare curriculum for the start of classes at CSU. The city of Fort Collins is repopulated with young eager minds, ready to throw a party.

Anyway…Eric and I got started with the layout for stepped dovetail splice.

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This is the first time that I used a level in combination with my center lining. In this case I really only cared about the flatness of the top face, and after leveling that top face, dropped a vertical line across the end grain with a level. The implication is that perpendicular marks across the top for the joinery layout are marked out square from the center line, not the edge of the timber. I’m still learning the potential of this center rule method, its a very powerful technique.

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Eric got right to work after layout, showing a natural speed that had me concentrating to keep up. So cool to work together, always watching out the corner of your eye for some new technique, like the apprentices of old.

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This is a good example, body position relative to the chisel locked together by connecting the hand with the chin, paring an end grain surface.

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The joinery came out well for me, and we learned a lot finding the hiding surface that was proud in Eric’s joint while drinking some refreshing iced white tea.  Even though the timber was uneven, the center lines came together nicely.

The next meetup has been scheduled, I look forward to it greatly. It is these personal connections that lead to real growth in our craft.

Cutting wedged mortise and tenon/ box joinery.

Saturday, Sep 5, 2015, 12:00 PM

Location details are available to members only.

2 Members Attending

The first meetup of the Japanese Daiku study group was a blast! Let’s continue on with the exploration of classical Japanese timber joints, to cut the wedged mortise and tenon. All of the basics of good joinery are included, accurate preparation of the lumber, center line layout technique, use of the saw and chisel.What tools should you bring? Goo…

Check out this Meetup →

 

Making Hikouki Kanna (Kumiko Thicknessing Plane)

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I dediced to take a break from the fuigo build to make a hikouki kanna. Actually what happened was that I’ve become really tired of the intense morning light that shines through my shop windows. I want to make a set of screens to cover the windows, but had told myself I wouldn’t do any more shoji work before making this tool, used to accurately plane thin strips of wood to thickness.

Odate refers to it as Kumiko-Kezuri-Kanna, and there are western examples as well, but if you’re looking to buy one online its ‘hikouki’ kanna. Just a touch expensive.

“Hikouki Kanna” By Inomoto

Des King references it as well: Hikoki Kanna, although as he mentions in his book on shoji, he thicknesses kumiko with a bench top drum sander before a final finish planing. I suppose that’s both fast and accurate, but I’m not yet at the point of needing such a machine.

Kanna for Planing Kumiko

This is what I started with to thickness kumiko. Its a very cheap 50mm kanna from Tools From Japan with home made runners on the bottom that determine the finished thickness. Its a small plane, so I can only work one piece at a time.

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The problem with that is wood moves.  When you cut thin strips, they’re going to warp a little. This is a picture of some 1/4″ Hemlock kumiko, the worst warping off the saw that I’ve ever seen. It was a shame too because the board had such nice tight grain.  When you go to plane warped material to thickess it wants to flex up off the planing beam and push into the cutting edge, even when the depth has been reached on the bottom runners. The result is a lack of dimensional control. I’ve resorted to finish planing each piece with a dial caliper to check in several places along the length of the piece being worked. With care and attention its possible to keep things within a few thousandths of an inch, but terrible slow and tedious.

Consider that Odate relates how his master could plane kumiko to thickness by touch alone. Obviously I have much to learn, but in the mean time there is a better faster way.

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Cut the dai. I’ve blogged about the process in an earlier post, Making a Dai. For this second dai I used ink on layout, and added a center line to the bottom and top of the block. It measure 11″ in length, and was built to fit the one large blade that I own, and change among various dai. I’m really getting my money from this blade!

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I also used a center drill to start the holes that house the sub-blade holding pin, no worries of drifting off the mark like last time. Placing this hole still feels iffy to me, thankfully the sub-blade has a forgiving amount of flex to it.

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The magic of the hikouki kanna centers around a small spring loaded bamboo bar that pushes the kumiko flat in front of the mouth of the plane, insuring it lies flat to the planing beam. To help hold it in there it sits in a sliding dovetail cut into the dai. I’m a big fan of using wooden cut fences for starting dozuki cuts. Here’s a simple one made out of some kind of nice tropical hardwood cut for a thick veneer. There’s a lot of work where you won’t have space to use a cut fence like this, in which case a scrap piece of kumiko works great. I just give it a little lick to help it stick to the wood while I’m starting the cut, haha. Even though the cut will be angled to match the sides of the dovetail I start the kerf perpendicular with a few strokes. I also used my rip tooth dozuki, even though this is cross-grain, because the teeth are less liable to catch and break off in this oak.

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With a clean straight kerf started the saw is angled to match the dovetail, same as with a jiguchi rail extension cut. I also cut down the center of the dovetail so that the waste is easier to clear out with chisel.

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A nice clean sliding dovetail, ready for the spring mortise. Notice I still haven’t cut the mouth open wide enough to let a shaving pass through. I wait to do that until the blade is bedded.

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As for flat spring stock, you can buy it I pretty much any size or thickness and then temper it yourself. As it is saw plate has close to the right temper for a spring. A good Japanese saw might be too hard to work without breaking from the fatigue, stick to the softer cheap plates that are closer to a purple temper, they’ll probably last longer.

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I settled on a thinner spring from a disposable ryoba blade. I have no analytics as far as the required force for the spring. The drawing in Odate’s tool book shows an adjustable tension mechanism with screw adjustment. I can see how that’s useful if you’re planing a wide range of thicknesses. The simpler way is to just bend the spring until it has enough bow to give good tension. I also peened it a bit on the anvil to set the curve and stiffen it up. I used to work as a musical instrument repair technician, flutes to be specific, which use a lot of very small flat springs and wire springs (I’ve been told I have a talent for small exacting work). Seriously, you just bend it to change the tension.

I cut a mortise in the bottom of the sliding dovetail to house the spring.

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Small parts require tweezers. If nothing else you gotta have a good pair on hand to pull all the splinters you get out being a woodworker.  The mortise for the spring has to be deep enough that it gives it full housing when the bamboo bar is depressed. So, I can’t say how deep to make the mortise, that depends on how you bend your spring.

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My bamboo bar, from pre-finished bamboo flooring. Somebody send me some fresh bamboo! This stuff sucks for making sumisashi. I planed it to fit, and then made it loose enough that about 1/16″ sticks out proud of the sole. It needs to be planed down in thickness as well, such that it can be pressed slightly below the sole of the dai.

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Here’s my smoothing plane for comparison. Really the closest I could make to a copy, but with American red oak and not Japanese white oak. The next time I make a dai I’ll try hickory.

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The runners on the bottom need small recesses cut to let the bamboo bar stick out. I also cut a little notch to keep the blade edge from pushing out the runners.

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I tried it on a few pieces of practice kumiko and it held tolerances of four thousands of an inch, right on the money for good joinery. If I flatten my planing beam again it might do even better. This plane is also wide enough to handle two pieces of kumiko at once. It represents at least a four fold increase in the speed with which I can dimension material, awesome!

Cutting Okkake Daisen Tsugi (Rabbeted Oblique Scarf Splice)

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Peter, who stopped by last weekend, was kind enough to let me photograph a set of old Japanese chisels he had picked up on etsy. This set is quite characteristic of some of the great deals to be had. I forgot to ask what the cost was, but it was probably close to the cost if you bought new only the 48mm chisel on the left.

I really love to see the worn down chisels. You look at that and think, don’t you want to have a bit more registration surface on the back of your chisel when paring? I suppose by the time you ware that much steel off in sharpening, you don’t need the large flat, you can just pare flat.

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I made the layout for this joint to show my guest Peter, it not being strictly part of project mayhem. It sat there looking at me in such a compelling fashion that I had to go ahead and give it a try. My first oblique splice, among the many variations of this joint that exist!

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Because both halves of the joint are very similar they are divided into the upper wood and the lower wood. I’m finally starting to realize how the sashigane speeds up layout. I’ve been using 1/2″ as a sort of nominal gauge for a lot of the haunching and, in this case, rabbeting marks. The sashigane being 15mm wide, it is used for the same purpose, but directly, so no measurement is required, you simple use the tongue of the square as the reference.  I recently ordered “The Complete Japanese Joinery” and am hopeful that it can give more insight into these time and accuracy saving uses of the sashigane.

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Before I begin describing the cut sequence, a note. Cutting a joint like this where the two haves are almost the same is great practice! What I quite obviously did wrong for the first half was corrected, and the second half actually gave me the chance to apply my new found knowledge.

I started the first half with the rip into the main cheeks of the scarf. I started the cut with the saw vertical, and then rotated the timber so that I could saw along in horizontal fashion. Its definitely a new skill to turn the saw on its side. I seem to let the top of the plate rest on the bottom of the kerf, producing a cut that slants upward away from the line. Its difficult without more experience to get a feel for the saw in the cut. If you stand up too much you’re bending the saw and things go awry, kind of like swinging a golf club.

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I stopped the rip cut when I realized I hadn’t thought through where I was going, and cut the shoulder line so that the rip had somewhere to meet up with.

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Paring such a large flat surface was difficult! Too much time spent carefully checking with a straight edge, and very easy to gouge in and remove too much material. The surface quality of my cheek suffered as a result.

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I marked the taper that draws the two halves of the joint together in assembly and made a series of waste cuts to the line for the lower cheek, which were then chopped with a chisel.

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Don’t you just hate it when you’re paring across the grain on a cheek and blow off part of the line? The line is all you have.

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In any case, the cheeks were pared flush and the layout finished for the through pegs that lock the joint. Evidently the square peg gives you the option of using a double wedge to lock the joint and tighten incrementally.

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The housing for the rabbeted tongue on the tip of the scarf was chopped last, after sawing to the line on both sides.

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For the second half of the joint I wised up, starting the cut with the rabbeted nose so that I had full support while paring the surfaces. For the cheeks I started with the shoulder cut and repeated my horizontal rip to the shoulder, and then immediately made the series of waste cross-cuts that allow the waste to be chiseled out for the lower cheek. Now there is room to plane the top cheek surface with a kanna, incomparably easier than paring. At the size of these joints you’re basically paring the face of a small board, the kanna makes sense.

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I took the fence off of my skewed rabbet plane to pare the lower cheek. I’ve never used this plane to pare such a large surface, it was awesome and fast.

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The first fitting of the joint was really disappointing. I know from previous experience that I could pound on this joint all day long with a sledge hammer and it would never come together. Bring the hammer out for the last 1/16″ or so of fit and not before, its better than waiting for rainbow farting unicorns to descend and push the joint together.

I spent a bit of time looking at the joint, trying to figure out what surface was proud. It must have been a small error in measurement, my sashigane technique. That is, marking one side of the scarf slightly longer than the other. I had to pare down the rabbeted nose on the left in the photo, as well as the shoulder that forms it, by almost 1/16″ before the two halves met nicely. I just don’t imagine having the luxury of repeatedly trial fitting a joint like this if the scarf was connecting two large, long, and heavy ass beams.

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I already had some cherry scrap planed to 1/2″ square, so that’s what was used for the draw pin. Because of how the joint slides together, I would think that trying to use the draw pins to force in the last little bit of fit could lead to splitting along the cheeks of the mortise walls.

The first meetup for the new local Japanese carpentry group will be next weekend. I’ve been surprised at the level of interest in such a short period of time, it will be an awesome experience to work together for the first time, figure out what can be accomplished when we learn together, even if just to drink a beer and joke about our mistakes. I had in mind that this joint, or a variation thereof, would be the work of the day and I encourage anyone to step up to the challenge. If you don’t have a little bit of an ‘oh shit’ moment when you first look at the joint, then you probably need to practice something more complicated.