Japanese saws– salvage the junk

 

One of my new favorite saws is an old piece of junk.

 

 

Found in a water filled wooden tray, out in the wilds of Hawaii, it had some unusual company. A good (albeit rusty) saw set, a pre-1917 Disston keyhole saw, a 1950-ish rip kataba Z-saw (stamped Honolulu), and a weird Swiss-army saw/multi blade thing, among other stuff.

 

 

Well, I cleaned off some of the rust and it's not so bad really.

 

 

It's no work of art, just a tool, but I'm liking it a lot more than I had expected. As a "cut down anything then forget it outside in the rain" kind of tool, it excels. I've found that it holds a good edge, and the spring and temper was well done. It had no kinks when I found it, and we haven't introduced any new ones, despite our best efforts. The saw back is taper ground to a knife edge, so much so that I can use it as a machete for thick grassy stems. It has proven itself to be deceptively capable.

 

 

As is expected, it could do with some improvement.

 

 

It has probably been sharpened a few times already, but the nib on the nose still stands proud of the teeth. It needs to be made even with the teeth. More importantly, the teeth height is uneven, one side being longer than the other. Whoever was sharpening it had a definite "strong side". I know that because I do, too. Because the teeth are longer on one side, the cut drifts to the longer side, binding the saw at about 2" deep.

 

 

And, as I was saying in the prior post, the saw teeth are still not as clean as they could be. Let's see if I can improve things a bit.

 

Scrape 'em clean.....

 

 

.....then polish 'em up a bit.

 

 

FYI, sandpaper isn't the best way to do this, but if you do, try to rub parallel to the tooth itself. If you rub back and forth, it mostly cuts up the sandpaper and rounds the tooth shape in undesirable ways. Anyways, the sandpaper method didn't totally ruin anything, and may have helped improve the teeth marginally.

 

I use the edge of a really hard oilstone instead. It's WAY better. I just do the minimum required to get the outer face of the tooth bright. No matter which method you choose, this does reduce the amount of set some (x)amount. The less you do, the better.

 

 

Sighting the length of the blade, you can see that the nib at the tail of the saw stands proud as well as a few odd teeth.

 

 

 

 

I joint the saw using a standard western mill file, running the length until I see a bright tip at each tooth.

 

 

I joint at each sharpening, because I'm training myself and my body. If I was REALLY good, I could probably get away with 1 joint/ 3 sharpenings, but what's the harm? You're only going to get better if you work on refinement, and in my head is a picture of a saw with teeth of a perfectly even height, not just "good enough".

 

 

 

 

And what do I get for all my high talk of standards?

 

 

Haha! Missed a big 'ol dip...whoops! I see a bunch of low teeth, mostly on one side, my "strong" side.

 

 

Maybe two. Jeez.....what a hack!

 

 

When I sharpened, I changed the tooth geometry a little bit, but that's for the next post. I've been thinking about and researching saw teeth for nearly two years now, but it's only recently that I've been able to test the saws so rigorously. Living this off-grid, extreme bush lifestyle, I am cutting live wood, green sticks and lumber, lumberyard "dry" Wood, and a fair bit of aged salvage lumber as well. And lots of it.

 

One of our new neighbors kindly offered to bring over his generator and a bunch of saws for me to use, after I told him that I was cutting everything by hand. You try to explain that you are actually enjoying the act of cutting the wood, and anyway, you can't easily cut much of this stuff with power saws and....you get that half perplexed, "huh.... OK, whatever" look. It's good to have such generous neighbors though.

 

 

Even though the tooth height is less than perfect, it still cuts well.

 

 

The cut through this hard (wet) Ohia went faster than you'd think, and the saw tracked straight and true, no binding anymore. I guess that I improved it some.

 

 

The wet wood shows scars easily, but it looks like a couple of teeth are set a tad more than the others. The scars look worse than they are, and I can't feel them by hand, but it's not perfect yet.

 

Because the saw is severely taper ground, it probably had very little set initially, and after a handful of sharpenings, it's probably about ready for asari/setting again. The lack of set, combined with the light weight of the saw has the saw itself riding up at times, meaning that you need to maintain downward pressure as you are using it for a ridiculously deep cut like this. What's happening is that the improved saw teeth are cutting more efficiently and are making more sawdust in the process. The problem is that the teeth are still the same size that they were before, and now the gullets are too small to hold the additional sawdust. The next step for this saw would be to give it some raker teeth and a few deeper gullets, turn it into a little madonoko saw, maybe.

 

This saw is for smaller stuff, like 2" and under, but it's good to have the capability nonetheless. I was felling a couple of 6" guava trees yesterday with this little guy, and it was a bit of a struggle. Why I don't use my chainsaw is a mystery to me. Scares the birds, I suppose.

 

What I really want to write about are teeth. Japanese saw teeth.

 

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Some thoughts on sharpening Japanese saws– It's the little things

 

Lately I've been waking up in the morning and *reeeaaly* wishing that more people were writing about sharpening saws, Japanese saws in particular. I guess that I'm just obsessed, but saws have been in my mind for a while now, and I just can't get enough. 3 o'clock in the morning, and I'm wondering if it's too early to get out of bed and get back to work, sharpening more saws.

 

Yeah.....better not. It's too dark to see, anyways. Have I mentioned that we don't have electricity?

 

 

 

Almost nobody writes about this stuff, not even in the Japanese blogs. Sebastian has been doing a great job resurrecting the sharpening art, and Gabe is doing wonderfully with his big Maebiki-oga's, but.....I want more. What little I find amounts to :

• Here is a diagram of a rip tooth. Copy it.
• Here is a diagram of a crosscut tooth. Copy it.

 

 

 

 

 

The truth of it is that those directives are absolutely correct, and as a beginner, there is no better way. Look at what a "proper" tooth shape is, then emulate. When your saw starts to behave strangely, it's probably not your imagination, because they do get dull. Just because your saw is a superawesome Japanese tool, well.....it's just steel. Before it gets too dull and something nasty happens, point that bugger up. Freshen up those facets, it's not that hard. If your saw isn't too messed up, you merely copy what's already there. It's easy (almost). Assuming that you've got a decent, non-impulse hardened tooth saw....and a file.

 

 

 

Sebastian, Mark Grable and I went in on buying a Yahoo Japan auction lot of saw files, bought and shipped through the excellent kindness of R-K Trading Company (thank you, Murakami!). I'll tell you this....I'm never paying retail again! Admittedly, it seems like we did get a bit lucky, we got them so cheaply. I wish that we had bid on the other lots as well, but in any event, I now have an embarrassment of 75mm, standard cut, double edged yasuri feather files.

 

 

From what I've been able to determine, Japanese saw files come in a standard cut and a finer cut (called "aburame"). If you take two files, one standard and one aburame and place them side by side, you will see that not only does the aburame have a much finer tooth spacing, it also has a thinner cross-sectional shape. These particular 75mm files are almost a perfect cross-sectional match to my fine tooth aburame 125mm file, despite its being almost twice the size. All of these files are incredibly narrow, delicate creatures, but comparatively speaking, these 75mm files are bruisers.

 

These files are all NOS from an old hardware store or something, Tsubohi File Works and Co., God only knows how old....50 years? These files leave a relatively coarse finish to the saw teeth, not exactly what you'd want for a final sharpening. I've been sharpening every saw within reach, and so far I'm still using the first one that I pulled out of the box, so I would say that these Tsubohi files are both forgiving and VERY durable. What the hell am I going to do with the rest of the 4 boxes.....I need more saws, obviously!

 

Japanese yasuri saw files come double sided, as these are, and single sided fine cut, a seemingly rare beast. 80-90% of the files that I see at auction are the standard double sided, and this must be indicative of something. I see two immediate possibilities. Assuming that 50 years ago the manufacturer made an equivalent number of all types of saw files, we can see that everyone loved the fine tooth single sided files so much, that they used them all up. All that are left now are the sucky, hated, standard double sided files.

 

Or....

 

Standard tooth, double sided files were made in far greater numbers because they are such useful creatures and were used for such important tasks, that the stores needed to keep their shelves well stocked. I don't know, I'm just guessing, but I'm thinking that these files have a specific purpose.....and the fun is in the finding, no?

 

 

All this talk about files, but they are actually only peripheral today. Today is about the forgotten side of the tooth, the actual "side" of the saw.

 

 

I was working on a saw the other day and I took some pictures to get a better look at things.

 

 

 

Not horrible (aside from the gullets being sloped the wrong way....too much island bliss, I guess), but when I look closely at the "dark" side of the tooth facing the camera, I see little specks of light. Those specks will be tiny jagged areas, perfect for snagging stray wood fibers and clogging the action of the saw.

 

 

A few of us have been pestering Mark Grable mercilessly for tips and information, anything Japanese saw related, and he's been wonderfully forthcoming with his knowledge and experience. Often, the briefest statement will have broad influence, importance far in excess of its brevity. Nerdy though it is, I've got a document of "Grable'isms" that I read before working on a saw, and it's amazing how something that you've read a thousand times before, will suddenly being new insight into a problem you are having. Case in point, Mark has mentioned that it's difficult to know what you are seeing, if the saw is all dark and pitted with rust.

 

What?! Rusty saws?!

 

Being attracted to the old and neglected, all my saws are rusty to varying degrees. Check out these treasures.

 

 

The little rip kataba in the center you might remember as being the subject of an aborted series on saw rehab I never brought to completion. I may have "massaged" the poor thing to death, just as you can soften metal by using a planishing wheel. The narrow bladed saw just to the right of the kataba has become one of my favorites, though. Ugly, rusty little thing, but it's a handy blade shape for pruning and trimming green wood.

 

I've already sharpened this a couple of times –I'm currently sharpening the saws at the merest HINT of being dull–, but then I started thinking about the side of the saw tooth. This is the equivalent of the "back" of a plane blade. You can't get a plane iron sharp if you only sharpen the face and ignore the back.

 

Duh!

 

The simple solution to the problem is....well...I don't know.

 

Ignore please, my use of a file here.

 

What I am really doing is gently scraping any trace of surface rust from the sides of the teeth that are facing toward me. I'm using the forward edge of the file as a scraper because it is easily the hardest steel that I've got handy. Really handy, like, already in my hand, haha.

 

 

And for Sebastian.....This is the saw that I mentioned in you comments regarding your universal dozuki. It was originally a purely perpendicular tooth rip pattern, with all teeth being the same size. I gave it more of a short and fat crosscut shape, with a stubby top facet. I'm putting together a post on my experiments with varying tooth geometries, but it might be a little while before things slow down some.

 

This saw, like most others, has teeth with a slight set, so the teeth are slightly bent to a curve, not straight. To polish the side of the tooth requires a curved implement of some sort. I tried using a curved/rounded edge wooden block with some #220 sandpaper wrapped around it. A flat sanding block will just level out the sides of the teeth, leaving you a saw with no set. Binds-ville, man, Binds-ville.

 

 

It works, and if that's all you got, use it. It's a pain though, and the tendency of the sandpaper is to round over the edges of the teeth. That's bad obviously, so try to find something better.

 

 

Much better for me, was a little Washita sharpening stone with a radiused edge. Different saw, but the idea remains.

 

 

Hey! My saw grew another set of teeth! A synthetic stone was too soft for polishing the edges of the saw teeth. An Norton medium India slipstone would be perfect.

 

 

Edit: Added a pic Here.

 

Here you can get an idea of the polishing effect at the tops of the teeth, although these are far from perfect. Remember, only the teeth that are facing upward are being polished. The ones that face away don't matter. Small steps, incremental change.

 

 

More than anything though, this really seems to point out how skilled you are in setting the teeth, because every discrepancy leaps right out at you. It's a good opportunity to even things up, work on your Asari skills.

 

 

 

 

Of course, once I got started.....

 

 

The dark red stone next to the soap is a small offcut of a synthetic #1200 waterstone. I takes a few swipes with that first, to seed the surface with abrasive grit, then do the bulk of the rubbing using the much slower natural stone.

 

This revealed lots of lumps and bumps.....Oh boy!!!

 

 

 

Off to the anvil, just give me an excuse, any excuse.

 

 

The lighter spots are deviations from the average plane of the saw. Lumps. They aren't bad though, so my little tack hammer seems the proper tool. Many small strikes, focusing on the areas around the bumps more than the bumps themselves.

 

 

My point here, assuming that there is one, is that the smallest things can have large effects. The teeth of your saw will never be truly sharp unless the sides of the saw blade are clean and smoothly polished. A little bit at a time, if your saw looks as bad as most of mine. If I were to get the blade to a polished state, most of my teeth would be gone, abraded away in the process. Better is to sneak up on polished, taking a little off at each sharpening, so the edges get incrementally improved. With just a slight amount of work, I've probably made the saw 30% sharper, although cleaning and working the sides of the teeth actually dulled them a bit, so some touch up was required.

 

The big ryoba worked fine with those little bumps and dents along the blade, but as with the rust, it is better to have as straight a blade as possible. Less friction, and it's fun to hit things with hammers.

 

It's the little stuff, dontcha know.

 

 

Oh boy....it's finally getting light out. Time to sharpen something!

 

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ChoMasaru a la Sebastian.......

"

I am an edge tool kind of person. My passions are sharp and polished to a beautiful haze and cleave wood as though it were an illusion. I love planes and chisels, axes, adze and knife. 

First, though, comes the saw. The saw is the primary tool, all others being secondary. I mean, think about it.... All of those other tools are only used to make up for the sawyers deficiency. We use the plane to remove the saw marks, and the chisels to pare to the line. In my deepest (darkest?) fantasies, I can wield the saw so skillfully, that no further work would be required. 

I used to detest sawing, seeing it as a necessary evil that should be completed as quickly as possible. Possibly that feeling originates with using dull tools? Japanese saws present me with a unique conundrum. When new, they are a pleasure to use but, as they get dull, they become progressively more difficult to use, wandering further from the line and grabbing, bending, then buckling. And breaking... Don't forget breaking. Japanese saws can break, oh yes.

The frustrations of a dull saw are common and universal, so much so that the saw market has shifted almost entirely to a disposable blade philosophy. When the blade gets dull, throw it away and pop in a new blade. Therein lies the conundrum...... I'm not a throw away kind of person.

The new blade is so nice, but each time that I use it, it gives me a little bit of sadness. I am thinking that  the blade will never be as sharp, the cut will never be as clean, the act will never be as much fun as it is right now. It's all downhill from here.

The disposable blades are impulse hardened, which is great, meaning that they are super hard, and stay usable for a longer period of time, but it also means that they are difficult to re-sharpen. You need a diamond grit yasuri file for that. Not to mention that I've been putting off saw sharpening for far too long and have very little experience, much less skill. 

Being who I am, need to be honest with myself. I need to use traditional (not impulse hardened) Japanese saws, and I need to learn to sharpen and maintain them. For me, this begins with research.

My Chilean friend Sebastian has been immersing himself in the Dao of the Japanese saw, and has sent me some of his early experiments in shaping a particular saw tooth design. 

There is a Japanese saw sharpener (a "metate", and actually soooo much more than just a sharpener) by the name of Nagakatsu/ChoMasaru that has been promoting a different style of saw tooth design. The ChoMasaru design supposedly cuts more smoothly, and requires less effort than more traditional tooth designs, but his work is seldom seen on this side of the world. 

Sebastian has been working on replicating this ChoMasaru design, in his ongoing effort to save every old, rusty and neglected Japanese saw that he can find. Obviously we are cast from the same mold, haha! You can read more at:

http://laborlimaetoolworks.blogspot.com/

The two saws that he sent me exhibit two different style of tooth design, but both share a common philosophy. They are intended for different uses, but work in a similar fashion. Cousins, perhaps?

The big 320mm ryoba (on top) has a standard ChoMasaru tooth, and is for cutting big stuff, rougher work on thicker stock. The smaller 245mm ryoba (bottom) is a "window" style (madronoko, I believe) that is designed to cut efficiently on a bias. It is intended for finer, more detailed work.

The big 320mm is bigger than anything I've got, so for comparison I need to use a smaller 275mm ryoba. That is one big ryoba!

The cut quality (in Port Orford cedar) between the two is very similar, despite the 320mm being a much larger saw. The size of the saw generally determines the size of the saw tooth, with a smaller saw usually showing smaller and more numerous teeth. Many little teeth result in a finer cut, but that's not the case with this saw. 

Although I was surprised by the quality of the cut, what really impressed me was the ease of use. This is a big saw, with good sized teeth, but it showed no tendency to grab or skip out of the kerf. It is nearly effortless to use, you just move the handle back and forth, and guide it the direction you want to go.

It's fast, too. I need to make a handle, pronto!

I tried the saw out on some Beech and Meranti, too. The Beech is hard, while the Maranti is soft.

Both cut beautifully, particularly for a saw this big. Notice the nearly complete lack of tear-out. That's surprising.

The madronoko saw is a more typical 245mm size, perfect for most of the work that I do. The window style has large gullets to get the sawdust out of the way of the cutting teeth. In the west we associate this style of saw with very coarse, timbering saws like lumberjacks used. 

I have another 245mm ryoba, to compare it to, that is my current baby. It's a nice saw and I am liking it a lot. 

Oh my.

Very easy action, and faster than my saw.

The cut surface looks planed, it's so smooth. Really amazing for a saw of this size, and with teeth that are relatively large, too.

The only reason that the cut is less than perfect is that this old saw has a couple of good kinks in the blade, making for some slow going at times.

And more than a few dents.

Each of the shiny spots is a dent that causes the blade to drag and slow down. The spots are shiny because they are rubbing against the sides of the cut, polishing themselves smooth. This blade has seen some battles.

The cut quality is every bit as good on the beech and maranti. Again, there is very little tear-out. If not for the drag imposed by the bent blade, this saw would be extremely fast. As it is...merely very fast. I give it a 4/5, haha!

As for fineness of cut, I can only compare it to my Nakaya D-210C joinery saw, commonly used for cutting kumiko for shoji screens, and one of the thinnest blades available (0.3mm thick!). This saw its fast AND fine (and a REALLY nice saw BTW).

Look at how tiny the teeth on the Nakaya are (32 dpi, I believe), compared to the ChoMasaru diagonal cut pattern that Sebastian made.

Close! Sooooo close! If not for the bent blade and a few errant teeth, these would be a match. The ChoMasaru might even be a touch better. As it is, the ChoMasaru shows better clarity and color in this Oregon walnut. That Nakaya is a surprisingly fast saw, but the ChoMasaru is faster.

And the scary thing about all this? These are some of Sebastian's earliest versions. He's gotten better. It kinda makes you wonder.

It sure works great for trimming doors. The handle is growing on me, too. 

Correcting a "chippy" blade...

I've got this great little kanna blade, 48mm wide and I use it all of the time. It has one significant problem, however. Try though I might, the edge develops little micro-serrations in some areas, and don't want to come out, no matter how much I sharpen.

There is a procedure called "Killing the edge" that often works to correct for this jagged edge tendency. When it is time to re-sharpen, you first drag the edge over something hard. A glass works nicely but the side of your sharpening stone works well, too. What you are looking for is a clear, unbroken line of "bright" that runs the full length of the edge. This line of clean metal ensures that you are into the fresh stuff, and not fighting some remnant scratch or blemish.



Some blades are difficult no matter what you do.


Right now at least, I prefer very hard blades. Sometimes the blade can be TOO hard, though. I suspect that the degree of hardness that the blade is capable of carrying is partially due to the underlying grain structure of the steel. A fine grain structure will support a very hard edge, where a more coarse grain will tend to chip or fracture. The grain of the steel is established by the blacksmith, so we are stuck with that, being what it is.

A coarse grain structure needs be softer, in order to maintain its integrity. Tempering is the act of softening a blade, and is something that is well within the abilities of anyone. Easy stuff.

Really.



Preheat the oven (I start at 325°F).

****
Preheat the oven, because your oven runs full-bore until it reaches operating temperature. The high heat would potentially harm the blade, so.... Preheat.
****

Place the blade on something large and heavy/dense.

Some ovens control their heat more accurately than others, and the cast iron skillet (in this case) acts as a buffer. A little extra protection (and I was seasoning the skillet anyways, so I got to kill two birds with one stone!).

I cook the blade for 30-60 minutes. The actual tempering occurs nearly instantaneously, but extra time won't hurt anything and may contribute to a more thorough temper.


After the blade is done cooking, let it cool, then back to the stones.

Not good enough. 325°F didn't seem to change a thing.

Magnification concurs. The jagged edge remains.



So, back into the oven, this time at 350°F for another 30 minutes, then sharpen.


Better, so at least I might be on the right track, but not good enough yet.


I try again at 375°F...

Much better, smooth and straight. I don't want the blade any softer than necessary, so I'll stop here, for now.

This blades jagged tendencies appear to have vanished, but I'll reserve judgment for now.


The blade seems to sharpen up much better now, both easier and "sharper" feeling.

The kanna works better. Nothing to write home about, but definitely good performance. The true test will be in the longevity and ease of re-sharpening.



I could possibly get more work done if my assistant would stop napping on the tools, though.

I was taking a break from all of the carpentry obligations of the last month, by spending a little time in front of the forge (Yay!!!! Hammer time!!!). I am trying to salvage a sloppy laminated blade that I forged a few months ago. After a lot of massaging, I've ended up with something that is getting close to being a proper blade.

The heavy lifting in the shaping department has been taken up by the $Store sharpening stone. This is proving to be a favorite of mine, being soft enough to function as a waterstone, but hard enough to hold its shape without immediately dishing. And it cuts fast! Amazing performance for $1!


I only tempered this blade to 325°F , and it's WAY too hard for a kitchen knife. Harder than anything that I've ever used before, anyway.

Even worse..... Chipping at the edge.

I tried a second temper at 350°F, and it might have been sightly better, but still chipped pretty bad.


So.... I skipped right to 400°F.

375°F would've been perfect, haha! 20/20...

400°F didn't ruin it by any means, I just like to be more thorough about these things. You don't learn as much if you skip the proper steps, you know?



Unfortunately, this blade is a junker.

This little crack will propagate. I could take in the edge a bit.... Regrind the bevel...


The tip would need some work too. See how the end looks all fuzzy?

That's because the hard steel runs out and gets mixed in with the soft iron. The tip is too soft. The "fuzziness" is due to the way that the iron finished on the natural waterstone. The hard steel finishes to a near-mirror state. I could grind the tip back until I get to the better steel......


Even though the steel is now soft enough to *barely* form a burr, it still tends to chip out.

*hmmm*

I don't want to temper the blade any higher. It's soft enough already (actually it's a very practical, hard edge. I just want to see *how* hard I can make a knife!)....I am wondering if I could improve the steel structure through a series normalizing/grain reduction heats, at the forge, and do a new quench...... Re-shape the blade...... Sharpen again......

The new blade would only be, ohhhh.....a paring knife maybe?

I've already spent an unreasonable amount of time grinding out that uber-hard bastard, what's another hour?

Good practice.