Tuning a Japanese hand-plane

I posted this item about how I tune my Japanese smoothing plane on my website yesterday, and I thought it might be of some interest here.


The weather has been a bit all over the place over the past few days, and while I was waiting for the finish on a couple of frames to dry, I checked my finishing plane for movement. The changing weather had affected it, and it needed to be tuned. It wasn’t too bad, and normally just a couple of minutes with the dai-naoshi kanna would have fixed it, but thought I would completely tune it from scratch, and put the photos here to show how I do it.

This is my finishing plane for rails, stiles and narrower pieces, so I have three touch points, shown in the next photo: what we would perhaps naturally call the front of the plane but is actually the back (daijiri) - 1; the area forward of the mouth - 2; and the front (daigashira) - 3. The surface between these three points is slightly concave so it doesn’t touch the wood being planed. The plane therefore “glides” along the planed surface on these three points. Because this is my finishing plane, these concave areas between the touch points are relieved only very slightly.
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This is what I use for tuning.
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Yes, it is sandpaper, and it works well: 220 grit sandpaper stuck on to 16 mm MDF, the plane being tuned, my dai-naoshi kanna (a scraper plane), and a small gennou for removing the blade. I also use a chisel.

First, I retract the blade slightly so it’s protected from the sandpaper, but down far enough so that it still applies the normal tension to the dai. Then I completely flatten the sole (dai shitaba) on the sandpaper using a normal planing motion.
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If you’re concerned about grit from the sandpaper attaching to the plane (it didn’t seem to worry any of the master craftsmen instructors at the College in Japan where I studied), you can wipe the sole with turpentine or the like after using the sandpaper.
Once the sole is perfectly flat, I then start on the concave areas between the touch points.

First, the parts to the left and right of the mouth. I simply use a chisel to carefully pare away a small amount of wood shown by the red arrows.
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I now work on the concave area between touch points 1 and 2. To start, I simply turn the plane around so it’s perpendicular to the sandpaper, and carefully sand the required area. Care must be taken not to sand too far either to the left or to the mouth.
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I then use the dai-naoshi kanna to cleanup and refine this concave area. As an aside, I always sharpen the dai-naoshi kanna blade before I use it. The sharper the blade, the better, cleaner and faster it removes fine scrapings of wood.
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Next, I work on the concave area between the mouth and touch-point 3 (daigashira) with the dai-naoshi kanna.
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I also use a sharp chisel to scrape away wood from near the mouth. This gives more control close to the mouth, and prevents the possibility of accidentally scraping away parts of touch-point 2.
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Once I’ve finished this, I check the sole lengthwise, across and diagonally for alignment of the touch-points and clearance in the concave areas. The area in front of the mouth is especially important.

After I’ve finished the dai, I check the blade. I sharpen often during use, so I have to tap out (ura-dashi) quite regularly.
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Here, the flat (ito-ura) is becoming quite narrow, so I’ll need to tap-out at the next sharpening session.
This is my finishing plane, so I progress through the grits up to 12,000. I use Shapton stones - 1,000; 2,000; 5,000; 8,000; and 12,000. For my non-finishing planes, I stop at the 8,000 stone. After sharpening I put the blade back in the plane and give it a try to make sure the tuning was successful.

And…
Attachment 167676
the proof of the pudding is in the eating.

This process took about 20 minutes, including sharpening the blade, and juggling around with a camera in one hand.
This is how I do this process. It's quick and efficient, and it allows me to get back to the job with minimum delay.

Hope it's been of interest.

Des

Des,

Fantastic! Thanks very much. I like the idea of the sandpaper across the dai to make the recesses.

Regards,
Garry

Nice work. :D

I personally think the #220 sandpaper might be a little too aggressive/coarse. #400 was recommended to me when using sandpaper, but who am I to poo-poo it when it obviously works?

Very pleased to see this actually. :2tsup:

Stu.

Just one more thing, when you do ura-dashi, can you document it please? It's one of them 'scary kanna things' that I need to take the hex off if I can, and showing that's it's not that scary would be very handy indeed.

Oh yeah, Shapton Glass Stones? How do you find them working for you, especially on Japanese tools?

Thanks Garry.

Stu, the 400 grit would take too long. This is a sun-pachi (70 mm) plane so there's a fair bit of oak to sand off. 220 isn't particularly coarse, and for the initial flattening, the sanding is along the grain so it leaves quite a reasonable finish on the surface. Sanding the concave areas is cross-grain and a bit rougher, but these parts don't touch the timber, so it doesn't really matter. In any event, I clean these areas up with the dai-naoshi kanna as I refine the recess.

The point to remember here is that this initial flattening is needed only when the plane has moved out of whack a fair bit. This one didn't really need the whole flattening process, just a touch-up with the dai-naoshi, but I thought it would be interesting to document the process from scratch. A couple of shavings and the timber has burnished the touch points at any rate, so they become nice and smooth very quickly, regardless of the sandpaper grit.

I was planning to show the ura-dashi process next time. It can be a bit hair-raising the first couple of times, but it's one of those things where practise makes "less bad".:wink:

I use the Ha no Kuromaku (Professional?) Shapton stones, and I noticed the typing blunder in the main text. It's a 12,000 stone, not 10,000 (I've corrected that on my website too, so thanks). I've used the Shaptons for quite a few years, and I like the way they feel and cut.

Des

Hi Des,

Great description of the process and with obvious super results.

One small aspect that I rarely see mentioned, but is vital and eventually encountered, is grinding back the mimi (ears) of the blade so the cutting edge width is never wider than the width of the dai mouth. Maybe you can discuss this when you post your blurb on ura-dashi?

Thanks for posting this,

Steve

Quote:

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Originally Posted by Des.K.

Hope it's been of interest.

Des

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Always interesting!

+1 for a thread on ura-dashi.
.

Thanks for the documentation.

I'd also like to see your ura-dashi process. I always feel a little scared tapping mine out.