Thursday, July 11, 2013

Out of tune......or "How to make your old kanna sing again"

Japanese carpenter's wood planes (kanna), man I love these things! Whisper thin shavings that actually leap from the body of the plane leaving behind a surface so smooth it shimmers, it's like magic or something. They look deceptively simple with only a chunk of wood for a body that looks almost exactly like a lumberyard 2x4 and a couple of chunks of steel stuck in the top......but they are ooohhhhh so much more. There are serious subtleties at work here.
Japan-tool "Rangiku" by Chiyozuru Sadahide

 This is an incredible masterwork. For sale at Japan-tool. I don't want to know the price. Great site, knowledgeable guy, and !VERY! good taste. Fair prices, too. I would love to have a tool this nice (hint, hint) but in reality, it would be too nice for me to use and that would be a shame. I make tools and the thought of one of them just sitting on a shelf somewhere is flattering, I suppose. Truly flattering would be if something that I built is a favorite tool that gets used by someone skilled enough to understand and appreciate it. I bet the guy who made this would feel the same. Personally, I prefer to buy an old beater to start out with and then maybe someday, when you know what you're doing, you might be ready for a kanna like the beauty shown above.

This might help you out if you are the adventurous type and it really isn't hard. Just take it slow and you might be surprised how well your old junker performs. To make the most of this process, first get an education. There are some great tutorials out there already, I am only adding a few additional wrinkles that I find helpful.

The first step is sharpening. Even if your kanna comes super sharp (good luck), it won't be sharp forever.These forum posts are by So, who owns Japan-tool. Rock star.

Plane blades part 1
Part 2
Part 3

Next is Mafe, on setting up a kanna. He lives in Denmark. He's my hero.

Kanna setup and sharpening

More, by Wilbur Pan. Another cool guy I'd love to hang out with. Too bad he's on the other coast.
 Plane setup

Most/all of the planes that you buy will need work. Some are better off in the trash. I think those are the most fun. Just buy something that has a blade worth keeping. This is a catch-22. An old, used up blade was good enough to use until it was nearly gone, but when you are starting out you want a bigger target to hit when you're adjusting the set of the blade. On the plus side, a shorter blade is easier to sharpen because the bevel is wider and blade is less top heavy. I wouldn't worry about it, to be honest. I have yet to get one that won't work at all. What I mean is that NONE of the planes that I buy will work without some attention, but with some effort......

I set up all of my planes to be high performing smoothing planes, at least to the extent of my abilities. Bear with me, if this seems too hardcore. For starters, we will focus on the basics of fitting the blades to see how well this guy can cut. I will address tightening up the throat and inlaying wear bars in a future post.

Here is what I do.

Japanese carpentry plane kanna
Buy a plane

kanna blades

Preferably one that isn't so bad that it makes you sick to your stomach to look at it. Or one that was run over by a truck. Not too rusty. Light surface rust is OK. This plane was used by someone who knew what they were doing. Most carpenters use a steel hammer to adjust the plane blade, which deforms the blade all to hell (I use a small wooden mallet because I haven't made a bronze one yet) and are too busy to fiddle around, tapping out the blade back (ura-oshi). This one is nice. The plane as a whole was perfectly adjusted, many years ago. By the time I got it, it had warped significantly and the plane body (dai) had shrunk tight around the blade.
I pared about 1mm, laterally, from each side of the slot that the blade sits in (no pics, sorry). That gave me 2mm width of wiggle room, which is plenty. Don't trim the top surface of the slot, pretty much my only "don't". You are only working on the broad lower bed that the blade rests on.

This is the plane that we are working on, a big pencil, a couple of chisels (one is a skinny 3mm),  squares, plane adjusting mallet, a file, and a couple of straight sticks (winding sticks). You could do all of this with just the file and the mallet.
tools for plane repair improvement
Get your tools

Remove the blades and the chip breaker. The retaining pin should slide out to the left. You will probably need to tap it out with something like a nail set (or a nail). Because this will be a finishing plane, I want the blade to be a really snug fit. Not sledgehammer tight, but pretty snug. You can use my mallet in the above photo to judge how hard I can tap the plane. We are talking about smart raps, not hauling off and waling on the thing. This plane was well set up, way back when, but I know that after the dai is adjusted for warp and shrinkage (Shrinkage!), it's gonna be too loose so I go ahead and do a few practice fits, just to get a feel for the wood and the blade shape. This also cleans the blade bed down to clean, fresh wood and gives me the proper contour for......

Wood veneer business card shims
loose fix
Gluing in some wood shims. I have gotten 2 types of plane off of Ebay. Either the blade is too tight and the dai is cracked, or the blade is loose and there is a paper spacer glued to the blade bed. Plan on gluing in a spacer. I have used paper, but the wood one that I show makes for a better fitting dai. on this plane, I pared out enough material so that the blade actually extended about 1 or 2 mm out of the bottom of the dai, then I glued in this very thin wood spacer using yellow wood glue. The wood is actually some Maple business card material that I bought from Lee Valley Tools a long time ago. They still have it for the same price, twenty some years later. Go figure.

Wood veneer business cards.

Spread the glue, then tap the blade into position (not all of the way, but firm) and leave it for a day or so, then remove the blade and wait a few more days if you can. Trim the excess and you end up with...

kanna dai mouth opening
Open wide
From the underside, we are about 3mm shy of where we want to be. As you fit the blade, place it as neutrally as possible. Try to tap it directly on the apex so that you get it to sit evenly in the dai. Mine always lean right, but I still try. When you remove the blade, hit the dai at the outer corners, not in the middle or you will end up with a cracked dai.

Time to get fit.
Scribble on the face with a pencil
You need to use something to act as a reference marker. You can use pencil, ink, marker, oil, lots of things will work. The idea is the same. Ink the blade, then tap it into place.

carbon reference mark
Make it all go away

Remove the blade and pare down the high spots that were marked. Remember the file? I sharpen the end of it to a square, flat surface so that it acts as a scraper. It is easier to use than a chisel, because it doesn't tend to dig in. Also, don't forget to trim the areas at the outermost edges of the slots. Often, this is where you blade will hang up, so get the bed trimmed right to the very  edge.

Carbon reference mark removed
All gone


This is using a light cooking oil. Kinda hard to see

 Repeat......I did this about 6-7 times. I like to pretend that I'll get a perfect fit, but I never do.

Oil and graphite lead pencil together is my favorite

1mm to go
OK, stop trimming the bed for a bit.

And now for something completely different......

It's time to flatten the sole of the dai. Leave the blade about 1mm shy of the surface so the dai is in tension, but we don't screw up the blade itself. I use 220 wet/dry on a flat surface (here I'm using a granite floor tile, not perfect, but good enough).

More scribbles to erase
The three main areas that we care about are the bar closest to the camera, the bar just this side of the blade (as seen here) and the bar furthest away. I go for a three point contact because it works the best for me. So there. I marked the bars with pencil and we will sand until they are gone. The marks, that is.

winding sticks parallel
Not too twisted
Remember the winding sticks? Here they are in action. Pretty flat actually. Place the sticks on the marked bars and sight along the plane body to check for twist. Do some sanding, then check the sticks again.

Yeah, it looks the same to me, too

Looking good
More to come.............

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Like all of us, I am figuring this out as I go, so when you see something that is incorrect or flat out wrong (and you will!), let me know. This is a learning process. Real people and names, please. Constructive comments and questions are very welcome, but hate speak/politics are not! Life (get one!) is too short.

Thanks, Jason