Birthing a Hira-Kanna(common plane)

This blog has been quiet as of late, which usually indicates that not much is happening in my wood shop.  In this instance though, that is not the case.  I’ve been in the shop almost everyday trying to get my head around the Japanese kanna.  I’ve made a few dai (plane bodies), tried different bedding angles and made several mounds of shavings.  I’ve also had a couple of email conversations with folks well-versed in the kanna.  These conversations have led me to abandon my original idea of using the kanna without the chip breaker.

While I enjoyed success with my first attempts of creating a kanna with a slightly higher bedding angle and no chip breaker, I was assured that such a configuration would eventually lead to frustration.  Plus I was sacrificing surface quality with the higher bedding angles.  Not that the surfaces I was producing were poor, they were as good if not slightly better than those I could get with a standard #4 smoother.  By lowering the bedding angle however, I found that the surface produced was dramatically better.

Another issue I have been working through is to discover the cutting characteristics of the blades that I have.   Unlike most western plane blades, Japanese blades very widely in material and cutting ability.  Japanese plane blades are typically a lamination of hard steel forge welded to a soft steel or iron backer.  Each blacksmith has formulations for the blade steel and backer that they feel is best suited for certain applications.  This results in a myriad of possible combinations.  I now have three 65mm blades and there is a marked difference in their performance.  One is softer and easy to sharpen.  Making it a perfect candidate to become the workhorse of the three.  The middle of the three is a little tougher and produces a decent surface finish.  This one will be my truing/jointing plane.  The newest of the three is a used blade I recently purchased off of eBay.  This blade is by far better than the other two and will be my smoothing/finishing plane.

Yet another issue is the material for the dai itself.  I could easily order Japanese white oak blocks, but they are spendy and I am frugal.  A quality block of Japanese white oak for a 65mm blade will easily run $60 or more. I have American (eastern) white oak and it works OK, but my stock is on the thin side and the wood turns dark when oiled.  That dark color makes it difficult to sight the blade across the sole for adjustments.  So I rummaged around in the magic attic and emerged with what turned out to be a plank of hard maple 1-3/4″ thick x ~12″wide x ~36″ long.  So maple is what I will be using for this next build.

The eBay blade from Japan that I just received is by far the best of my three blades.  It doesn’t seem to have seen much use.  The seller guesses the blade is blue steel laminated to soft iron.  The brand name is Kuninori, but it is not signed by a blacksmith.  The chip breaker is a standard stamped steel affair, but works as intended.

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The first step was to prepare a block of the maple.  I cut it close to finished length, width and thickness.  Then I squared it up.  Once the block was ready I completed the layout.  The bedding angle for this plane will be 40deg.  I have been slowly accumulating bits and pieces of information on the layout for kanna and have worked out a charted proportional layout method that seems to work.  It’s not quite ready for public consumption, but I should have it ready soon.

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I like to start by chopping the mouth opening first.  I’m sure there are arguments for chopping the blade ramp and escapement first, but this works for me.

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Then I flipped the block over and chopped the blade ramp and escapement.  Then cut the slots that secure the wedge-shaped blade.  My apologies, but I neglected to take photos of that part of the process.  Plus I’m still not comfortable that I’m correct in my process.  So I’ll jump to a shot of fitting the blade.

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Pin and chip breaker installed.  Then a quick test cut, because I can’t help myself.

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I start conditioning the sole on sandpaper adhered to a glass plate.

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Then refine the conditioning with a scraper plane.  I set this kanna up as a smoothing plane which means two contact points.

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It works!

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I wont be winning any planing contests, but this will work for me.

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I’ll refine the conditioning a little as I go, but I’m pretty happy with how this one turned out.  Next up I’ll tackle the jointer.

Greg Merritt

 

 

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16 Responses to Birthing a Hira-Kanna(common plane)

  1. Salko Safic says:

    I shall start calling you a tool maker, it’s interesting how you find the low angle to produce a better surface. 5 years ago I replaced a low angle smoother for a no.4, I miss it though and wish I never did as I too found it produced a more polished surface. Many will disagree but each to their own.

    • Greg Merritt says:

      Tool maker is a pretty big stretch, but thanks.
      So far I have tried 50,45, 40 and 38deg bedding angles. All work perfectly well. The main difference being the degree of polishing/burnishing produced by the lower angles. If I typically used a film finish, then 50 or 45deg angles would have been fine since I would also typically sand the surface to provide tooth for the finish to adhere to. I like to use oil though and the planed surface will be the final surface. Hence the desire for a polished surface straight from the plane.

  2. Jonathan Elliott says:

    Greg,

    Thanks for sharing, excellent work and very interesting to hear what you have learned from your experiments. I’ll be interested to see how the jointer comes out and your thoughts as you continue to use these. Making some kanna will be in my future so I find it particularly interesting. Thangs again!

    Jonathan

    • Greg Merritt says:

      Thanks Jonathan. I may even be confident enough in my process to post more details as to how I go about building these. I plan to start work on the jointer this weekend…hopefully.

  3. bpholcombe says:

    Nice work Greg! You are a glutton for punishment chopping one out of maple. How tight is the mouth with the blade fully installed?

    • Greg Merritt says:

      Thanks Brian. The maple is tough stuff, that is for sure.
      As you know, adding the chip breaker to the equation changes the geometry of the throat. I opted for a slightly open mouth and angled the throat so that the geometry will remain consistent as I condition the sole. A super tight mouth configuration will quickly degrade as the sole is conditioned. Since I’m still trying to learn to use the kanna, I felt that consistency in performance would be my better option…at least for now.

      • bpholcombe says:

        When I started using Japanese planes I was coming from western planes, where an open mouth (1-2mm) is usually no concern when using a chip breaker. However I found that using a kanna with an open mouth caused snipe at the end of the board. Not talking a huge mouth, about 2mm. I ended up closing it down with an insert and then tuning the wear until the chip could flow freely.

        • Greg Merritt says:

          I’m well aware of the snipe now. I matched the wear angle to the secondary bevel on the chip breaker ~80deg. I would guess the mouth opening is 2mm or a little less. Slightly skewing the plane in combination with speed and shifting hand pressure seems to work well in eliminating the snipe. In reality this kanna would be classified as an intermediate smoother. I’m saving my pennies and building my skill and will acquire a wider, high quality blade. I’ll make that into my one-pass super smoother.

  4. Coisas EM'adeira says:

    What a very nice report!
    I enjoy reading it, and its great to follow (and share a bit) your progress!

  5. Brian Eve says:

    Nice!

    Those shavings look like you are doing something right. And the plane looks good. And, I like that you used maple for it. It should work great.

  6. angosturabitters says:

    an inspiring post! someday i hope to crest the make-yer-own-dai hill. i like how you made it work with the hard maple.

    • Greg Merritt says:

      Thanks! You should just go for it. The way I look at it, if I fail, which I do, I’m only out a chunk of wood and a little of my time. So really nothing to loose. At the very least I always gain experience and a little insight.
      The maple is what I had. It is tough to chop, but seems like it will make a nice and hopefully durable kanna.

  7. Very nice, Greg. The only award a plane really needs is the one for making fine shavings. And you won that award with this plane, hand down. 😉

If you don't comment this is just a fancy way for me to talk to myself.

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