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!

29 thoughts on “Making Hikouki Kanna (Kumiko Thicknessing Plane)”

  1. That’s awesome Gabe. You do have a talent for precise work.

    I can totally see the course now: day one jig making; day 2 hikoki kanna; day 3, 4 and 5 lamp making with kumiko work.

    1. The local daiku group that’s I’m starting is also a trial run for me teaching. If it works out we can make your idea happen, it sounds great. I still have a long way to go learning the various kumiko patterns, I’m really looking forward to tackling the mistu-kude three way joint for hexagonal jigumi, some of the pattern potential is just stunning. If you can get Des Kings two books on shoji/kumiko design, do it. It does have me thinking about making some of those specialty ‘v’ cutter pattern planes for producing the really tiny pieces of kumiko in great numbers. I’ve never even seen them for sale on an English language site. Being able to forge a proper tapered and laminated blade is where to start. There are a good handful of shoji/fusuma makers in the US here, but to my knowledge only a select few can do the more complicated pattern work.

        1. Really great store, I could give those guys a bunch of my money, too bad all of the ha-ganna are sold out, I really would like to know how much they cost.

          The next meetup will be this Saturday, should be an interesting time, I’m really looking forward to meeting people and working together.

          1. sad, last time I checked a few months ago they were still there 🙁 I keep an eye for you in buyee.

            Here saturday I will make the students cut mortices on the 6×6 for the smaller horizontal beam. I find really amazing that it was so easy to start all this. Things are happening here and there, I love it.

          2. So true, I wouldn’t be trying to gather other people together if it wasn’t for your work. If you truly want to get something done that is good and right, the people will come, and generally the money can be found. The last obstacle is always government preventing things from happening.

    1. Thanks Mihai! If you had told me a year ago that I needed to make one of these I would have really struggled to get it done. I really look forward to putting this plane to work, see if I can improve it.

  2. I’ve got some bamboo that I’d love to send you, not too nice, but it worked for sumisashi.

    Ooooooooo, wait a bit and I’ll get some of the black stuff. That will be cooler!

    1. That would be so excellent! I need to think of something equitable to send you in turn, let me think on that and come up with some ideas.

    1. Thank you! Funny you should ask about Raney, I left a comment on that page a couple of months ago asking if he could show another photo of the interior of the hold down mechanism. He said he would try to get a picture or two up, but I’d guess he’s been too busy of late. I decided to start at the simpler end in terms of design complexity. If the flat spring I’m using doesn’t hold tolerances consistently I’ll look at a redesign, part of the fun is figuring this stuff out. I should give it another prod, maybe he didn’t understand how serious I am about this stuff.

      I actually lived in Virginia for many years, though I wasn’t much of a woodworker then, too young. How about bald cypress? Hemlock works very nicely as well and the prices are good, though I haven’t worked with it enough to be certain its a good idea. By far most of the kumiko I’ve cut has been from old growth doug fir with nice tight grain. I like the contrast of the heartwood to the sapwood when it shows up on the frame pieces. So besides getting some nice port orford cedar or yellow cedar it really comes down to what you find has good working qualities and doesn’t go crazy warping off of the saw. For hardwood I’ve tried cherry and it works very nicely.

  3. Gabe, I saw on your “about” page that you got a music degree from VCU…I’m an instructor of theory/ comp at JMU. Small world. Though the number of woodworker/ musicians who blog is so large as to defy the laws of probability…

    Thank you for the suggestions on appropriate kumiko timber. You’ve given me two great ideas. One, cherry is easy to get around here, so that’s worth a try. Two, I lived in Cali for many years and VG doug fir is one of my favorites, splinters and all…I go back once a year and could easily get some and ship it home. Thanks for the ideas!

    1. Haha, I’ve noticed that too, lots of musician/woodworkers out there. Tom Fidgen is a good example, doing both at the same time. What is it about studying music that leads to woodworking?

      1. A desire for good instruments, perhaps? I loved making the kantele I made a while ago; I rushed it over to a friend without taking a picture, though. Hoping to make a 10 string personal model soon, though!

  4. I’ll have to give this a try one day! Would Eastern White pine be a suitable shoji material? Found a great source for it! Are you going to make plane blades? It’d be awesome to have American-made Japanese-style tools available. I’m thinking W1/W2 laminated with Wrought or Mild steel, in hickory dais.

    Oh, and if you have a ton of bark, a book I have says old timers in the West used bark scales as their forge fuel. This seems intriguing; I do have a piece of hickory bark in my forge that has outlasted all the charcoal so far.

    1. White Pine should be fine as long as it has a good straight grain and tight growth rings. Also, it helps if you enjoy how the wood looks. I wish I could be making plane blades! I’m eventually going to give forge lamination a try, but its a hell of a skill to get good enough to make a basically decent tool, let alone a laminated ‘v’ gouge. Where are the American blacksmiths that can forge a good plane blade? They’re all focused on knives and swords. I’ll give some pine bark a try next time I light up the forge, the pitch content should make a hell of a flame.

    1. Thanks! I looked all through the website of the link you posted, they don’t seem to list a price for the ha-ganna, perhaps its a special order type of thing, in which case, seriously expensive. Perhaps it would be worth sending an email to Des King who could suggest where they could be best ordered, and find a tool agent to make the purchase and ship. My kumiko-zaiku is still at a basic level, I have a lot of patterns to practice through before I really need the ha-ganna. I want them badly though!

      1. Me too I also need to practice a lot (just finishing my first andon with asanoha side panels) before needing those nice ha-ganna, and also want them badly 😉

        The idea of having someone to forge is tempting as well (and making the body in the shop). A friend just quit his job as a programmer to be a full-time forger, but he said he is not yet capable to produce the folded blades as in a ha-ganna (well maybe the time he gets there with his forging skills my kumiko skills would also have increased).

        I think Des would be kind enough to indicate someone in Japan, but I agree it can cost a lot as he said that in the book.

        1. hey guys, have you seen the 60degrees v chisels from pfeil for example? I got one that pretend to convert into a ha-ganna some day, and I guess they have like 3 angles, 60, 90 and something else… maybe. Will show you a picture in next post.

          1. Good idea, I see that they make 60, 90, 45, 35 degree v chisel. How about the math to figure out what angle a 35degree chisel will cut when bedded at 38degrees in the dai?

          2. Now that I think about it, that is exactly the kind of problem that should be solvable with carpentry drawing in layout.

          3. Sorry for the delay, descriptive geometry is probably the same thing you (@gabe) referred as “carpentry drawing in layout”.

            If you want more info, you can find a course on DG with this link: http://www.andrew.cmu.edu/user/ramesh/teaching/course/62-175

            The problem we want to solve is (well you guys already solved it): given the angle we want to be cut in the kumiko’s mikomi and the angle of the dai (you mentioned 38Degrees), what should be the angle between the blade’s wing.

          4. exactly, I can give you the answer but rather let you find it yourself 😛

            Think at the the 2 limit cases where the blade is angled at 0 or 90 degrees. Then 45. The general case should be clear after that.

          5. A bit of descriptive geometry would solve the issue about the angle you get when the chisel is not parallel to the surface to be cut. No explicit math need to be done 😉

          6. Could you describe that a bit more, or link to something that does? I went ahead with my rusty algebra and did the math, but I know there are elegant ways to work it out in layout.

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