The Art of Setting Up a Japanese Hand Plane - Kanna

Over the past years I've become increasingly enamored with Japanese woodworking tools. However, the Japanese woodworking tool that sets itself apart from all others, western and eastern in my opinion, is the kanna. The humble forged kanna is a utilitarian plane that is customizable, versatile, and leaves an exceptional finish on wood of all types. As kanna come only partially set up, I wanted to create a comprehensive video guide to help beginners and intermediate users set up and/or elevate their kanna. I encourage everyone to watch the video first and utilize this article as more of a gap filler and guide to the video itself.

Supplies

Usable Japanese hand tools that are widely available on Amazon: https://www.amazon.com/shop/cowdogcraftworks/list/2M7FE6DH0V4Q6?ref_=aip_sf_list_spv_ofs_mixed_d

A collection of basics to create a simple setup for sharpening Japanese tools: https://www.amazon.com/shop/cowdogcraftworks/list/2HMI0XMUARCTS?ref_=aip_sf_list_spv_ofs_mixed_d

Books that I find helpful and instructive on Japanese Woodworking: https://www.amazon.com/shop/cowdogcraftworks/list/1D7RACW0KO8NL?ref_=aip_sf_list_spv_ofs_mixed_d

Dale Brotherton's Sharpening and the Japanese Hand Plane in Depth: https://hidatool.com/item/2620

Books in Japanese:

Help You Understand Japanese Woodworking Planes: https://shop.kurashige-tools.com/en-us/products/new-help-you-understand-traditional-japanese-planis

Help You Understand How To Set Up Japanese Woodworking Tools: https://shop.kurashige-tools.com/en-us/products/famous-japanese-woodworking-planes

Step 1: Flattening the Backs - Uradashi

When it comes to creating a usable plane, the plane must be sharp. Sharp is oft defined as two surfaces coming together at an edge with as few imperfects as possible. In order to do this, one of those surfaces must be established, or in the case of planes with a chip breaker, two flat surfaces must be established, one on the back of the blade, and the other on the back of the chip breaker.

Flattening backs can be done with two methods, uradashi, also known as tapping out, or grinding, lapping the back on a series of water stones. Uradashi is the traditional and more preferred method. However, for those who find that to be too advanced, lapping on stones can be equally as effective. I in fact did not perform uradashi for the first year with Japanese tools and solely lapped on stones. However, it should be noted that the hollow on the backs of Japanese tools is designed with sharpening efficiency in mind. It allows for the user to remove a minimal amount of material to get to flat and the user can alter the shape if it ever becomes distorted, very quickly and very efficiently to achieve flat.

I should also note that the entire backs of planes do not need to be flat. Unlike certain styles of chisels which utilize a completely flat back to ride a reference surface, the edge of the plane blade is the only point that is coming into contact with wood. Therefore, the land or itoura, the area north of the ura so to speak and leading to the cutting edge, is the only area of the blade that needs to be flat. The same goes for the chip breaker.

In the video, I go through great detail on uradashi and what the user is trying to acheive. Uradashi involves tapping the bevel of the laminated steel blade, for the purpose of displacing the soft iron to alter the shape of the hardened steel that forms the cutting edge. It is easily the most intimidating practice that Japanese woodworkers do in terms of the catastrophic effects that poor practice can have.

One of the main keys that I've been taught is to cluster most of your strikes towards the center of the heel and only lightly move left to right. The idea being that as the material is moved from the center, it will push outward and move the hardened steel around it. Repeated strikes at the edges of the blade tend to be in the least supported areas and can cause a crack.

Step 2: Sharpening - Shaping the Bevel

Sharpening is one of the most controversial topics in woodworking in general. As such, in the video I don't spend a lot of time talking about who or what is right and wrong. I won't do dwell on it here either.

Japanese blades are often sharpened freehand. The bevels on Japanese planes and most Japanese chisels, with some exceptions, are quite large, making them comfortable to do without a jig. The are traditionally not micro-beveled with the exception of the chip breaker (more on that later). I'm often asked why they're not micro-beveled and in terms of Japanese chisels, I don't have a great answer. However, in terms of Japanese planes, the answer is quite simple. The edge of the plane is fine and the plane is structured in such a way that the edge is what makes final contact with the wood to be planed. I hear a lot of western woodworkers who have experience with wooden foreplanes talk about wood on wood burnishing as being the reason that Japanese planes leave exceptional sheen. However, as the rear of Japanese planes are relieved and does not touch the wood ultimately, what you are in fact seeing is the effect of a stout, sharp blade being the last thing to touch the wood.

What a micro bevel on a Japanese plane can do is create an additional contact point on the blade that prevents the edge from making contact with the wood entirely. The result being that the plane won't cut at all, or if it does it has to take an aggressively thick cut. Neither being desirable clearly.

I go through a bit of an obsessive sharpening regimen, but most folks can get away with a 400, 1000, 3000, and 8000 setup with a lapping plate to flatten the stones. At this step in plane setup, I encourage worrying more about creating the general shape of the blade as opposed to getting to final quality sharpness as accidents can happen during plane setup with your blade, so it's not always worth it to put the blade completely through its paces.

"To strop or not to strop" is something that comes up often. When I was transitioning into Japanese planes I continued to strop my blades for a couple of years. In Japan, there are plenty of folks who use green compound and a leather or wood strop. However, I prefer the practice of abrading the burr on my highest finishing stone. For me, that's a natural stone, but when you reach "the final boss" of your finishing stones, simply alternative passes between the bevel and the back to abrade the wire burr off the edge of your blade. You'll be able to tell this by using your finger on the back and the bevel and you'll usually be able to detect in which direction the burr is folding until it finally abrades off. Sometimes you can see it come off on the stone itself if you have keen eyes. However, your sense of touch is quite strong and I encourage people to feel for the burr or lack thereof.

Step 3: The Dai - the Plane Body

After the blade is of the proper shape, the next step is to fit it into the dai, or the plane body. In the video, I break this up into two sections, fitting the blade itself and tuning the bottom. However, in this Instructable, I'll combine it into one. Using either a chisel, or a blunted chisel set up for scraping as I did in the video, you slowly pare down the high spots of the bed and test fit the blade until it either meets or slightly protrudes from the mouth.

Rubbing oil and graphite on the blade where it meets the bed and tapping it into the body will show the high spots. You ultimately want to have even graphite across the bed to show that you are having even contact. It is EXTREMELY important to not take too much material and do this very slowly. While there are ways to fix a loose blade, maintaining the integrity of your block by having a nice tight fighting blade is paramount to successful use and adjustment. I prefer everything to be a little too tight as opposed to too loose. Also, because these are wood bodies, I recommend letting these planes sit for a while in your shop to get acclimated to your temperatures and humidity levels and I recommend setting them up in drier seasons (or climate controlled environments I suppose) so that when the wood swells with humidity, the fit will be tighter as opposed to looser.

The mouth should be as tight as you can get to the blade while still being able to allow a shaving to pass through.

In terms of the bottoms, there are generally two variations. Two points of contact for a smoother and three points of contact for a truing plane. The points in common are at the front and just in front of the mouth of the plane. Each strip is about one centimeter across the width of the plane. With a truing plane, theres a third point of contact at the rear of the plane. This contact point keeps, for lack of a better term, the plane on plane once the blade exits the wood so that the planed surface remains flat with no snipe.

There's a variety of ways to relieve the bottoms. I've actually seen dai maker Koyoshiya use a jointer to relieve the back behind the blade. I do not recommend this, but keep in mind, these bodies are wood and as woodworkers, there's almost infinite possibilities on how results can be achieved so long as the results are consistent with the desired goal.

Step 4: Uragane - the Chip Breaker

Perhaps the most powerful tool in kanna use is the uragane, the chip breaker. In the video, I go over a couple schools of thought on what is going on with the chip breaker and why it is so effective. I for the most part subscribe to the idea that the chip breaker is pre-tensioning the edge of the blade. I want to be clear on this point as some folks believe that the chip breaker is designed to tension the blade itself or "hold it in place". This is not correct.

As steel wants to flex, the edge of the kanna which is incredibly fine wants to vibrate and chatter through the cut. This causes increased friction and heat, and can lead to tear out as well as chippyness in the blade edge. The chip breaker, which is micro beveled, is set as close to the blade edge as possible without passing it, to apply tension to that edge and reduce or eliminate as much of that movement as possible. Furthermore, the micro bevel also "breaks the chip" and creates a lack of structure in the shaving that Japanese planes are quite famous for, the "snakeskin" shaving if you will.

It is important to make sure that there is the perfect amount of tension between the chip breaker pin and the blade itself and when not in the body, the chip breaker must rest on the blade without any rock or wobble between the two. If there is any adjustment needed, the ears on the rear of the uragane may be adjusted by bending or flattening.

In analyzing proper edge tension, I've begun to look for a slight light distortion in the edge of my blade, indicating that the uragane is applying pressure to the edge in such a manner that it is tensioning it appropriately.

Uragane setup can be fussy. However, when it works correctly, it truly is a miracle in practice.

Step 5: Troubleshooting and Use

At this point, your kanna should be functional. As an aside, I will test my kanna before fitting the chip breaker, with just the chip breaker in the body but not properly set to assess fit and shaving clearance.

To set up your kanna, tap in your blade until just before it protrudes from the mouth. Tap in your chip breaker until just before it is at the very edge of your blade. It is important to note that these two components are independent of each other. While they can sometimes protrude or retract together, they for the most part will move separately in the body and should be adjusted as such.

When trying to set up for a fine setting, I sight down the bottom of the plane. I tend to try and have the plane and my eyes facing a white surface to make it easier to see the blade protrusion. Blade protrusion should be as faint as possible. If you see a line as thick as a typical mechanical pencil line, you are set to take a monster shaving. I want to barely see a faint black line just peeking out from the mouth. For an extra fine setting, sometimes you can't even see that line and I'll touch the transition between the mouth and the blade edge to feel for the protrusion. Just don't cut yourself here.

How can you tell when everything is singing perfectly? When you can take an equal thickness shaving with and against the grain without tear out and leave an exceptionally reflective surface.

"My shavings appear to be clogging? Now what?"

There could be a variety of things happening here, typically related to the chip breaker. I would first start with the mating surfaces between the chip breaker and the blade. Double check to ensure that they are contacting each other perfectly across the cutting edge. Any light that is coming through indicates a gap, even if small, and shavings can stick to the edge of the chip breaker, compile, and clog in the throat.

If the contact is sound, it could mean that the area on the inside of the mouth is too tight and the shaving is clogging deeper in the throat. It should be noted that I'm not referring to the mouth itself, which should be kept as tight as reasonably possible. It's the area inside the mouth. The shaving is potentially coming off the chip breaker too tight to that area inside the mouth and folding in on itself and clogging. It's also worth it to check for any stray splinters or chips in the throat towards the mouth. Sometimes a "hang nail" of sorts can cause snags. This is probably the least likely of causes, but I've seen it happen nonetheless.

Step 6: Final Thoughts

This subject is something I'm extremely passionate about. This video, at this point in my Japanese woodworking tool journey, is the culmination of all my education and experience. From someone who four years ago built a barely functioning plane out of wood that doesn’t even grip the blade correctly, to someone who can regularly set up a plane with a minimum amount of screaming and cussing. This video, has been one of the most requested by my small but dedicated audience and I’m happy and proud to provide it.

Filming this video was not easy. I tried to talk through in real time a lot of the steps. For some reason I got hooked on the term “overcooked” and said it about four times in thirty seconds at one point. The work is time consuming, so certain sections have to be sped up to be able to show how long some of these processes take, but make it tolerable to watch. I used “thought bubbles” to try and convey certain ideas and concepts after the fact because the subject is so deep and so nuanced that I couldn’t accurately and succinctly convey things with spoken word alone. I recorded the entire section on the uragane (chip breaker) without audio on the first go around and had to go back and record an after the fact tutorial on it. In my opinion, that section is unfortunately the biggest failure of the video. However, there’s clear dedicated chapters so that the viewer can use this is a reference material later during set up and tuning and I believe that all the major components are there, especially if one is utilizing the books suggested in the closing comments of the video.

Hope you like it. Let me know if it’s something you found helpful and if there’s other things you’d like to see on the channel moving forward.