Showing posts with label ChoMasaru saw tooth design. Show all posts
Showing posts with label ChoMasaru saw tooth design. Show all posts

Sunday, June 14, 2015

Lazy day, but looking forward to some mayhem ( and saw straightening #3).


Cats have got it all figured out.



After a hectic and stressful week on the mainland, punctuated by a distinct lack of sleep, I'm back home in Hawaii, thank god.



Gabe (http://granitemountainwoodcraft.com/) has got me thinking about files, you know, the ones used for cutting steel. As everything gets progressively cheaper/crappier, there are increasingly more people that are searching for a decent file.


Handmade tools can elevate the mundane to the sublime.


Beautiful.


Anyway, after thinking about files all morning, I remembered that Sebastian's "Project Mayhem" begins soon, and I am woefully ill-prepared. I need to finish up some of these tool projects that I've been working on.


A few weeks ago, Sebastian sent me a wonderful tsuki-nomi ( like a really huge chisel) and I have slowly been making it shiny and new looking. After scraping the handle clean, you can see that there are a few areas of iron staining near the ferrule.

 


Bring on the Jasco "Prep and Prime", a dilute phosphoric acid mixture that is commonly used to treat rusted metal. I find that it ( or "Oxpho", same stuff different name) is one of the only ways to remove the rust stains from wood without causing any appreciable change or discoloration to the wood itself.

Just dab a bit of the solution on the afflicted wood, then let it sit for a while. 15 minutes....1 hour, or in this case, overnight. Iron stains....vanished!


The real reason that I pulled out the PnP is that I need to get back to my Japanese saw renovation project. Since the phosphoric acid darkens the steel slightly, it serves as a dual purpose indicator dye.


After a few minutes, the saw blade has darkened nicely.

 

 

I like the phosphoric acid for rust treatment because, being roughly as thin as water, it will wick into any little nooks and crannies, slowing or stopping any new rust formation. The forge welded tang on this great little saw would be an unfortunate place to develop any corrosion.


And while I was waiting for the rust converter to "convert".....



My anvil has seen better days, and the face has been pockmarked by errant blows of the hammer. Since I am getting serious about tuning up this saw, I had better tune up my anvil a bit as well. A smooth anvil makes for smooth work.

 

My little shoeing anvil will never have a totally smooth face, but at least I can knock down the high spots, haha. 30 minutes of work, using a carborundum stone and bearing down hard, has it looking better than it has in years. Wonder of wonders, it's even flat!


Still, 30 minutes......Sometimes I miss having electricity.


So, the point of darkening the blade of the saw is that now all I need to do is take a few passes with the stone and the high spots on the saw plate are revealed.

 


I don't want to grind away material, as that would leave a saw with thick/thin spots. Probably not the end of the world, but it's not what I'm after.


The amount of work remaining on this saw is minimal, but requires more finesse than I have been using so far. Now, in a perfect world I would be using a nice little cross-peen hammer for this but I don't have one, so I make do.


I am going to start referring to this as my "Swiss army" hammer. One side for ura-dashi, the other side for saw straightening.....this hammer does it all.

I have slightly eased the corners and curved all edges, to minimize the likelihood of leaving any new marks. Oh yeah, it drives tacks, too.


 

A round of light tapping using primarily the corners of the hammer, followed by a brief stoning, shows how effective my hammering has been.

After one round of tapping, the bright spots are both smaller and more numerous. I am only using light taps, barely more than the weight of the hammer. You could do this all day and not get tired, as the rebound from the anvil does nearly half of the work.



Better yet after two rounds. I unpacked a pretty little Washita stone to use, instead of the big carborundum I was using. Not only does it fit the scale of the saw, it also just feels better.

Some very interesting patterns are beginning to be revealed. Underneath the random lumps and bumps is the evidence of structure and intent. This saw was shaped and carved. Very cool.

Unfortunately, it's getting late and my light is fading. I am looking forward to tomorrow's daylight.

 

Sunday, May 31, 2015

Japanese saw tuneup - straighten out those kinks! ( part 1)

 
 
Although the day began bright and sunny, as is typical for this area it is currently raining. Great for growing plants, and the rain water that I used yesterday washing clothes has been replenished (and then some!), but this weather really makes me question my sanity. Why haven't I built a workshop yet? Have I finally succumbed to madness?
 
Back in the days when I lived in the "Great white north", I would think to myself how wonderful it would be to live in an area with less extreme weather, warm days and never any snow......Paradise! Think of all the work I could accomplish!
 
Now that I'm here, all I want to do is sit and listen to the birds sing, the rain drip, listen to the earth breathing. Island time mentality? You wouldn't believe how loud the frog's cries of love can be! Some people find the calls debilitating, but I just revel in all of this. Possibly this is still my juvenile infatuation with Hawaii, but I still blame my fear of the mainland on the trauma of moving here from Oregon....... but I don't know how much longer that one is gonna carry me,haha.
 
 
 
 
 
Anyways, the other day it was raining.......and I've been thinking a lot about saws.
 
 
 
Since some people have asked me about my workshop....
 

 

Here it is. 4" x 10" of pressure treated glory. It has a bronze screw towards the front right corner to act as a stop for planing lumber. Andre Roubo, eat your heart out. At least the last 2 feet stays dry.....sometimes.

 

 

 

 

 

2 seconds ago the water was jetting out of the downspout, but now it's just a trickle. At least the barrel is full.

 

 

 

 

It's a rainy day......what better thing to do on a rainy afternoon than hammer on some saw blades!

 

 

 

My Chilean Internet friend/Japanese tool aficionado Sebastian (http://laborlimaetoolworks.blogspot.com/) sent me this 240mm beauty just before we moved here, a well-loved Ryoba that has been converted (by Sebastian) into a madonoko, with a ChoMasaru style tooth.

http://mypeculiarnature.blogspot.com/2014/12/chomasaru-la-sebastian.html

 

 

 

 
Sebastian cut all new teeth on the crosscut side of this ryoba, filed in nice deep gullets (which gives these saws their "window-saw" name, madonoko) and raker teeth, all great stuff, sharp and pointy. This is a fast cutting little beast of a saw that also leaves a remarkably fine surface to the cut face, similar to my uber-fancy Nakaya D210C kumiko saw that I mentioned in the previous post, except 4x faster.
 

Sebastian turned this abandoned tool box junker relic into a GOOD saw! One problem remains to be addressed. The saw exhibits a fair amount of drag in use and tends to bind in the kerf of the cut.
 
And here is why.
 

 

Bent. This picture is taken sighting down the length of the crosscut side of the Ryoba, and I can see at least two good kinks along the length. This was no surprise to Sebastian, but he is a generous guy and he wanted to reserve some of the fun for me.

 

 

 

So. Bent handsaw.....what do you do?

 

I don't claim to be an expert of anything, much less Japanese saw metate, but I do love this sort of thing. I'm not shy about hitting things with hammers obviously, but information on any kind of western style handsaw repair is, ummmm......cue sound, *crickets chirping in the night*......

This is all absolutely amazing to me. About 5 years ago, there was a brief upsurge in interest in western handsaws and how to sharpen them. Sharpen them..... great! Everyone needs to be able to sharpen their tools. How about those bent blades, though? Have you ever bent a saw? Did you try to fix it by bending it over your knee?

 

 

Around 10 years ago, Bob Smalser wrote a series of posts on straightening western style handsaws on the sawmillcreek forum and, to this day the series has become one of the only resources of good information on how to fix a saw that doesn't cut right. In the Internet world of virtual experts (*ahem*), Bob is one who knows what he is talking about. If you haven't read everything of his yet, you might start here....http://www.wkfinetools.com/contrib/bSmalser/strSawBlade/strSawBlade1.asp

 

 

 

The situation is far worse for Japanese saws. Not only is there less information on sharpening, there is almost none on actual repair. This is doubly unfortunate, as the blades on Japanese saws are both thinner and harder. As with the Japanese kanna, nokogiri are high performance machines. In careless or uneducated hands they can bend, and worse, they can break. What we are left with is the market shift towards disposable blade saws. And oddballs like me who wonder what it is that we are missing out on.

As an inveterate Internet scrounge, here is some of what I've found.

Japanese saws from a western perspective.

Starting here........http://www.ibiblio.org/japanwood/phpBB2/viewforum.php?f=12&topicdays=0&start=50&sid=099c531a7212504dbd72a9cf935f4a64 and more.

  • Mark Grable
  • Dave Burnard
  • Jay Van Arsdale
  • Scott Nehring
  • Jim Blauvelt

These guys all participated in the old HMS Japanese tools forum about 8-10 years ago. The info from just these handful of sources is better than the 95% of the crap out there....trust me. I can add actual links if you are feeling too lazy to do your own research, but the important fact is that Mark Grable studied with one of the last great Japanese saw makers, Endo Tomoya, Miyano Dai Endo, Yataiki (Miyano Tetsunoske III).

http://www.daikudojo.org/ShopTalk/yataiki_article.htm

 

The other guys are mostly just end-users, but seem to be good people and know their stuff. Dave Burnard is an actual hyper-enthusiast like me and was studying all sorts of super cool Japanese blacksmithing related metalurgia before he dropped off the map.....Dave? You out there? I've got some questions........have I ever!



Sebastian has been lifting the bar ever higher, in his quest for the best Japanese saw in the world. Well, actually, we seem to be two people, cast from the same mold but half a world apart. He too loves bringing new life to old tools, and possibly more important, what the process teaches you about life in general. He is a bit younger than I ( not much, though!) and still harbors faith in mankind's ability to act in its own best interests.....sigh. I'm not talking tools here.

As he has been teaching himself to sharpen and re-point Japanese handsaws, the purity of his intent has gotten the attention Mark Grable, as far as I can tell the only westerner who knows which-end-is-up about Japanese saws. Fortunately for me, I've been able to "eavesdrop" on a few of their conversations ( Boy, do I sound like an Internet stalker or what?!) by following the "comments" on Sebastian's blog. Mark doesn't write much, but what he does write is pure gold, especially considering the extreme lack of first-person knowledge on this subject.

Please keep in mind that these are brief tips from Mark to Sebastian, and were not actually intended to become instruction manuals on Japanese saw sharpening/straightening whatever. My sincerest apologies to all parties involved.


With Sebastian's permission, here are a few excerpts from his blog.

From:

http://laborlimaetoolworks.blogspot.com/2014/12/dozuki-rehab.html#comment-form

 

 

Mark Grable :

 

About straightening ...

1) work from both sides

2) work by halves - sneak up on straight little by little

3) don't focus on a couple square centimetres

4) don't hit harder than it takes to have an inspect-able result

5) polished smooth hammer faces and anvil

6) hardest possible anvil

7) heaviest solidest anvil possible

8) start on modern western softer thicker blades

9) clean rust free blades

10) light from front diffused no light from sides or back

11) flex blade from edges compressing between hands as it is held in front of you at eye level almost but not quite dead on edge, so that light glances past the blade, like the Sun at dawn, and dusk. flex one way, then the other, look at underside, then at top side. you are looking for shadows indicating compression which distorts an edge, an area in center, or ar neck, heel or anyplace. UNTILL THIS IS DEALT WITH, you can't get a flat blade.

12) use a one and a half - two pound hammer with a face 26 mm D and a convex surface 1 mm high at center to strike glanceing blows away from the compression, from edge of compression to edge of saw. IT IS TRIAL AND ERROR, so check frequently for results of say, six blows to a side. If it gets worse, change plans.

13) have a plan

14) if plan doesn’t work, stop and look at the situation; 90% is in not mis-perceiving because it's a twilight brain thing. Maybe Right brain.

15) Keep you Hara (navel chakra) clear - this is the energy the nokogiri will remember

16) It's only a saw. You are only You.

17) Know when to stop.


This is now my Bible. Better than some, I would say, haha!



Working thin sections of steel are not uncommon to other trades (Automotive bodywork comes to mind) so more research.....

 

Here is one of a few.....bent fenders anyone?

http://67-72chevytrucks.com/vboard/showthread.php?t=459877

Thin sheet metal work is not a subject that is entirely new to me, having fixed up seemingly innumerable cars back in the day, but never was the result of my endeavors so crucial. In my ignorance, I though that Bondo was how dents were SUPOSED to be fixed. Maybe I'm just getting old? Still, understanding the mechanics of HOW the saw manifests it's injury is important. I know that this is swiftly getting into the realm of TMI, but this is a little peek into how my brain works.



I should probably just jump in. Time for some pictures.

 

 

 

So I take a chunk of #1000 waterstone and briefly scrub the saw plate for a moment to reveal the bumps and hollows.

 

 

 

Far from flat, but it sure has a story to tell! Each of the brighter, sanded areas is indicative of a high spot that needs to be brought down. What is more important to me is that nearly every bulge and swell is a story.

 

 

 

If I zoom in a bit.......

 

 

Notice that right around the middle of the saw there is dark shadow 1cm wide that stretches nearly the entire width of the saw. This is the worst of the kinks. Someone was using this saw, the cut bound up and the saw bent just a little bit. Over the years, the cumulative damage manifests itself as a patchwork quilt of bumps and hollows. I love this stuff!

 

 

 

If you hold the saw obliquely, you can see how the reflection gets distorted by the imperfect plane of the metal.

 

 

 

 

 

To work on this poor guy, I am principally using two hammers here, a 2# ball-pein and 12 Oz. or so.

.

 

This isn't indicative of necessity, but just what I've got laying around. The bigger hammer is what I use for my general blacksmithing work, while the smaller is just for general work. The main point would be that a polished face is good, scarred anvil face (mine!) would be bad (Mark's # 5).

Nothing fancy to show, really, just tapping on (and around.....Mark's #3) the high spots, then flipping the saw over to address the other side (Mark's # 1 and #2, VERY important, work both sides!). Referring back to the images of the sanded surface, hit the bright spots, then flip the saw over and hit the opposite. If you hit hard in a "center" on one side, don't hit as hard on the reverse side.


If you only hammer one side of the saw, you'll end up with a potato chip. Think about this.

In one of Sebastian's prior posts, he gives graphic representation of what is happening to the saw from all of this hammer abuse.

 

http://laborlimaetoolworks.blogspot.com/2015/01/correct-me-if-im-wrong-straightenin-one.html

 

 

Take one large bump....

 

 

Give it a hit.

 

 

 

The force gets distributed to the surrounding areas.

 

 
Where once there was one large bump, we now have an undulating family of bumps and hollows. The bumps are more numerous than before, but smaller in size.
 
 
Do this enough times, you end up with a minutely rippled surface that resembles a flat surface.
 

 

 

 

So when I say that you need to work both sides, what does that mean, really? It is a bit tricky, in that you don't want to hit the EXACT same spot, because the that sort of negates the work that you have done. This might be one of those theoretical /practical dichotomies. In practice, you will be hammering the saw plate for......1000's of times? So things should even out here, I suspect.

I bang on the poor saw for a while, then lightly sand the surface using some halfway worn out sandpaper, to highlight the areas that still need work.

 

Notice that the low dark spots are fewer in size and number?

 

 

 

But I can't quite make the saw perfectly straight yet. Frustrating, yet.....

 

 

 

A small discovery.

 

 

This saw has been repaired at some point in the past.....awesome! If you look closely, you can see an old crack running transverse to the body of the saw, that has been welded! Right about middle of the picture, you can see that the saw has undergone a repair.

 

Ha!

 

No wonder I am having difficulties!

 

 

 

But still, I try and try and try and try. A few minutes every other day lets the steel relax between sessions. I have other projects to be working on in any event, haha. I'm not sure that the "rest" is necessary, but it meshes well with my general work flow. Is this another lesson? it surely can't hurt.

 

 

 

You might notice that the reflection is becoming clearer?

 

 

Getting better.

I know that much of this post has been both wordy and vague at the same time. I plan to go into this saw straightening in more depth, so if you are still interested, more is on the way.

 

 

 

 

One other note.

 

Hawaii is warm and humid, what am I doing to preserve my tools?

 

 

Macadamia nut oil, I shit you not, the best oil that I've found so far. Far better than anything else.

 

Kind of hard to find though.......

 

 

 

 

 

 

 

Monday, December 1, 2014

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:



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.