Tooth angle on a Japanese crosscut saw

 

My sincerest apologies to my friends who have been wondering where I've been for the last 2 months. Popular speculation had me suffering an unlikely and grisly demise, fallen to my death in some hidden lava tube, but no....

 

 

 

 

Our house on the mainland Oregon coast sold, and there were a few projects that still needed to be finished up before handing off the keys to the new owner. It's an ironic cliche that the carpenter's house is never finished and this is no different. The cobbler's children that suffer from lack of shoes, that sort of thing. You probably know how it is. Anyways, 3 weeks of intensive house type woodworking, flat winter's lighting and rain. Lots of rain. That's at least one thing that Hawaii and the Oregon coast share.

 

 

Having been in Hawaii now for just over one year, visiting the mainland again reminded me of numerous things that I seem to have already forgotten, but one of the most notable for me was the light. Daylight that is. There's not much of it, and what there is comes at such a low angle, it seemed as though everything looked just the slightest bit "off" to me. Shadows were long and the colors didn't look as vibrant. My iPad evidently forgot about the relatively northern light too. The pictures that I took are, well, not my best. Yeah, blame the camera, haha.

 

 

The stairway to the attic bedroom needed a door and handrail.

 

 

I had to get a bit creative, trying to squeeze a manufactured door and jamb into such a narrow opening, but I got lucky. Down the road from our old house is "R. Gray's bargain yard", a wonderful resource for scroungeing unusual building materials. The owner, Bill, came to my rescue yet again and found me an off-size, special order return that fit the opening, needing only a bit more massaging than your typical install.

 

 

It was fun to do some plain old carpentry again, so different from the stick and log work that I've been doing in Hawaii. After packing off all my tools to bring home to the Big Island, it felt funny to be packing them back to Oregon again, but at least I got to plane some wood. Electricity came in handy. I still miss my old tablesaw at times.

 

 

Ahhhhh, my old workbench......didn't ever get that project completed either, but at least the new owner is an eager woodworker. She'll finish it up nicely. She was psyched to keep my old saw and I'm glad that it found a good new owner.

 

 

I brought along a minimal assortment of tools, nothing fancy.

 

The TSA always gets a treat, looking through my baggage. They generally do a better job packing my bags than I do, and never skimp on the tape that holds the lids on he boxes, haha. A tough and thankless job, to be sure.

 

 

I was so happy to be planing wood again, I maybe went a little above and beyond on some of the tasks that needed completion. The attic railing (Port Orford cedar....such a great wood!) posts and balusters received a winding chamferred edge and a simple bridle joint attachment, draw-bored and pegged using bamboo skewers.

 

 

 

 

And finally, capped with some nice ribbon figured African mahogany that I was saving for a special place. The light was so bad, I couldn't get a picture. It definitely made the colors in the attic look off. Ewww, yuck!

 

 

If I ever figure out how to plane that curly, interlocked crap with a kanna and NOT get any tear-out, I'll share the knowledge. It's good to have goals, right? The 47 degree kanna that Dave gifted me would've been just the thing, had it been here – sigh.

 

 

So where was I?

 

Before I left, I had started on this post, some thoughts regarding an optimized tooth pattern for a Japanese saw I've been using for working green wood, but maybe this should be a WIP thing instead. Get this thing going before I forget what I've already done. An aspect of blogging that I love......I can show my mistakes. Maybe we both learn that way, hmmmmm?

 

So, spoiler alert. I'm not satisfied with this saw, so you might not want to jump right in and copy what I'm doing here. Not quite ready for prime time...... yet.

 

 

I need a general purpose saw that works well on green, sticky wood.

 

 

I've had this old bugger kicking around for a while, but haven't really felt the need to use it very often.....'till now. This was 1/3rd of a lot that I bought for $15 on eBay nearly four years ago and I guess it's time I put this thing into circulation. They sell even cheaper on Yahoo Japan, so have Murakami get you a bunch.

 

 

 

 

 

Felling trees, even the relatively small ones, using a pruning saw (much less using a trusted ryoba) is good meditative work, but when a tree is in danger of dropping onto my head, I want to get done with the task as quickly as possible, you know?

It's time to pull out the big(ger) guns.

 

 

 

 

 

The toothed length of this crosscut saw is a respectable 20" (about 510 mm) and the handle is nice and fat, perfect for two handed sawing. There are a few slight bumps to the blade that I still need to remove, as you can see from the slightly brighter spots on the body where it has been rubbing in the cut. Contact with the walls of the cut = friction, so hammering out the dents is a short list priority. You can also see a couple of lines of fairly severe corrosion that run diagonally across the blade. Bummer, but not the end of the world.

 

The farthest end of the saw where the teeth are largest has a vertical tooth angle. 0* rake angle.

 

 

90* and pointy, these teeth are similar to a rip tooth, but still have a front, back, and top bevel/facet.

 

 

I'm holding the file to show the approximate angle of the cutting face, around 75* or so. That would be 15* away from being a purely perpendicular rip tooth.

 

Not being the purely perpendicular face that you would see with a proper rip tooth, it's more of a hybrid, but this is a general purpose saw, I suppose. You might notice that I've already jointed the saw, the tops of the teeth are showing little flat surfaces.

 

 

 

 

As we approach the handle end of the saw, the teeth gradually assume a more relaxed slope.

 

 

These teeth are the familiar shape that you see on any crosscut blade, although the rake angle is more shallow than you'd see on a ryoba for instance, about a -10* rake angle. These teeth at the heel of the saw are probably shaped differently to make it easier to start the cut. The relaxed tooth angle gives a nicer shearing action.

 

 

The tooth pattern must have originally looked more like this example from a pruning saw manufacturer.

 

 

My saw is similar, but the saw in the photo above has both leading and trailing edges at much shallower angles, closer to 45* from the looks of it.

 

 

When I check my saw, the file shows a cutting angle of nearly 60*, so a 30* angle to the leading edge.

 

 

It's pretty much a standard crosscut tooth shape, although I'm going to try reducing the height of the teeth a bit, in orders to lend extra durability for cutting these dense Hawaiian hardwoods.

 

 

 

Rust is bad! Here is a closeup of the rusted area.

 

 

The tooth in the center has been polished using a hard novaculite oilstone and is tilted towards the viewer. Skip a tooth either direction and the two teeth at the edges of the photo are the rusty ones. The pitted rust on these teeth will prevent them from ever being truly sharp. Worse, the little pits will tend to hold onto little threads of wood fiber, increasing drag and tending to pull the cut to one side. Unfortunate.

 

 

 

 

So, this is all fine and dandy, but so far I am really just copying the tooth pattern as it is. The interesting points are that this saw has both a progressive tooth size AND shape. And of course, it has a hand forge-welded tang, the saw blade tapered in both length and height....all that good Japanese craftsman stuff.

What am I doing differently, you ask?

 

Every 5th tooth I mark with a pen, prior to filing the top facet of the teeth. The fifth tooth I will turn into a raker, to better clear away the wood waste.

 

 

 

 

I use the 5th tooth raker through most of the length, but leave the teeth closest to the handle alone.

 

 

 

 

 

In the interest of experimenting with saw tooth shape, I'm going to alter the shape of the teeth in stages, beginning with the rakers. The upper slope I'm going to start with is.....oh, maybe 12*, probably too shallow, although it's similar to the clearance angle you want for a plane blade.

 

 

Other than filing the raker tooth to a flat/chisel tooth, I leave the forward and trailing edges alone. It will be an admittedly crappy rip tooth shape, but I'm experimenting here, OK?

 

I give ALL the teeth a top slope of about 12*, but otherwise the other teeth are just copied as they were. Looking at the photos, I see that I need to work more on keeping my angles even from one side to the other. Everyone has a "strong" side, so it's just one more thing to give some thought to.

 

 

 

How did it work?

 

It cut. This is 8" of hard Ohia.

 

 

And.....it felt crappy, haha. Both slow AND grabby, the worst of both worlds! The saw was dull and slow before, but sharp(ish) and slow?!

 

 

How about something softer? A low quality fir 4x.

 

 

Awful. Those big ol' teeth grabbed those growth rings and tried to rip that stick out of my hands on nearly every stroke. The cut surface quality is terrible as well (at least for a Japanese saw). And slow. Or perhaps my standards are just too high. Nawww. It sucked.

 

 

So there ya go. Universal Japanese saw v2.0......epic fail. There are some obvious things that can be improved, tip slope angle being the principle suspect, but we'll have to see. It's rare that sharpening a tool will lead to a decrease in performance and this was pretty lousy, so something interesting must be going on. It sure gets me thinking.

 

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Weekend progress

 

Renee, being the hard working girl that she is, has a "real" job that occupies here throughout the week, has her crunching numbers, strings of crazy long gene sequences AND teaching a class and students as well. Thank god she can relax and take things easy on the weekend.

 

 

Renee is also like a little excavator in human form, and I don't know where she finds the energy (She's nuclear powered, I suspect).

 

On Saturday, she had a vision, then promptly started to make it real.

 

 

Or maybe she just couldn't stop digging. The woman is, seriously, just a digging maniac. Ellie is searching for leaves, and the neighbors dog is searching for Ellie.

 

We've got soil in abundance, lying all rich, loose and crumbly atop the lava. The Aluhe ferns that were here before, blanketed the area with leaves and other decomposing matter for the last few hundred years, eventually producing this wonderful soil. Soil is truly an amazing resource, something that too many of us take for granted, but not us. We are conserving every bit that we can. After living here for nearly a year, we have seen just how rare this type of earth is. More common is to have the barest skin of dirt lying on top of large sheets of lava. This is the first place that we've been where you can actually use a shovel.

 

It is common here to ask, "How is your land? Is there soil?"

 

 

Ellie has been making birds from various leaves found in the forest. This one must be a cardinal, judging from the crest on its head (the next step will be working on camera focus :-)

 

 

Our baby cardinal friend lives here somewhere, and it's my hope that if we would start laying out some food, we'd see him again. None of the cardinals are about, so there must be some better food elsewhere.

 

 

Dogs and dirt.....what's the attraction?

 

 

I'd say that she is hunting up a gopher, but I'm pretty sure that we don't have them here in Hawaii, certainly not on this side of the island. She's just loving the dirt, digging and helping out.

 

 

This is the place on Sunday.

 

 

She dug out a big pocket of soil, separated out the jumbled chunks of lava, then layed a solid base for a parking area. She's a monster.

 

 

This entire island we live on, soil, trees, food, animals, everything that we know and see every day....it's just a skin atop rock. Everywhere, the entire world is like that, but it's something that we've forgotten, most places. This miniscule layer is all that we have, that gives us life and sustains us. The big island of Hawaii is new, geologically speaking, and here we are reminded constantly that life is a short and wonderful thing.

 

The soil is life, and the lava underneath is the origin, the beginning. These volcanoes erupt continually, lava breaking free onto the surface and covering everything, then quieting down again for 10 years...100 years.... 1,000 years....

 

When the lava flows, it often covers, but doesn't always scour the earth. It buries. So what we are seeing as we dig our little garden bed, is evidence of a millenia of events. The lava comes, then life gradually colonizes. The native Ohia trees are some of the first to return, having evolved to be able to live in thin soil, putting out thin strands and clumps of aerial roots to aid them in obtaining the water they need, water from the air itself. Eventually you get a mature Ohia forest, which is what we have now. Then the lava returns, covers it all, and the cycle begins again.

 

Our little garden is thin lava, broken by time, atop more lava which is also broken, atop probably more lava. There have been many different lava flows here, and there will be more.....probably. The island is still moving, and as it drifts further from the thin spot on the Earth's mantle that caused the island to form in the first place, the island will cease to grow.

 

Anyways......dirt and rocks. Lots of dirt. Renee is in heaven.

 

 

She has exposed two ridges of lava, and right down the center, she is seeing in her mind a waterfall cascade of steps, the early stages of which you can see here, from the side.

 

 

 

 

The broken lava is an absolute joy to work with, coming in a wealth of different shapes, many flat surfaces, and some with square corners.

 

 

If you've done rock work before, you know that square corners are like gold, something to be saved and hoarded for the future. The rock above isn't a corner per se, but is even more unusual, shaped like an inverted "L". It's also blue in color. Renee is using blue and silver stones for the steps, placing the red and gray rock elsewhere.

 

 

And up above, she planted some Okinawan sweet potato runners.

 

 

This is a new favorite of mine, though I've never been a fan of sweet potatoes. This plant is gardener's ease personified, just drop it on the ground, place a few handfuls of dirt here and there on the runner stem and that's it. It will soon grow and spread everywhere that you let it, and it also works well as a cover crop/living mulch. The young greens and shoots are eaten steamed, and taste somewhat similar to spinach, minus that uncomfortable oxalic acid feel in the mouth. VERY tasty, both the greens and the purple fleshed tuber.

 

Part of being a good gardener (which I am emphatically NOT), is knowing what grows where. This is a new climate, and to be rigid in our thinking and demand that all of our old favorites be grown in the garden, well, that's just absurd. Normal potatoes, lettuce, tomatos, peas....there is a long list of what doesn't like to grow here, primarily due to the high rainfall. There is an entire new world of plants that DO love it here though, and "right living" comes from that understanding. Effect change where you can.....don't try change the plants (because they won't listen), change your diet instead.

 

 

 

I have a different set of time constraints than my wife, so I get to work on the new place most every day. I start out as I usually do, by clearing the building site of undergrowth, then piling materials dead in the middle where they are guaranteed to be underfoot, whether I need them or not.

 

 

I ran a stringline around a rough perimeter going from tree to tree at an arbitrary height above grade. The slope right here is about 1/10 and, where the patch of ground that Renee has been working has lots of soil, this spot has essentially none. That's why I chose it. It's a horrible spot to grow things. Keep life where it is most happy.

 

 

Raise the camera a bit, and the strings come into alignment.

 

 

The lines are level, but the camera is not.

 

 

 

Some of you might recognize some joinery here.

 

 

 

 

So honest to God, I drive myself crazy. This is supposed to be a simple elevated platform, a level surface from which to work, and a basic tin roof. I'm not even planning for walls. 80% of the materials are ugly and salvaged and I'm planning on using guava sticks for the roof members. A long service life is not a consideration, and take-apart modular is a minor design theme. I finally caved and bought a screwgun, so screws are here, nails are here, and I should just bang this out, right?

 

To all of you who know me.....I can hear you. Yeah, right, sure.

 

It starts with a simple splice......

 

This lumberyard 2x6 would feel so much nicer in the hand if it were planed....

 

Height above grade will be over 36" at the most likely side of approach, so maybe if the nicer sticks were used on that side, maybe introduce some curved elements......

 

And so it goes. I can't help myself. People kindly (and sometimes NOT so kindly, haha) call me a perfectionist, but it's not true. I'm an incrementalist. Perfection is an illusion that can never be attained, but nearly everything can be made just *sliiigghtly* better.

 

Naturally, this drives others crazy too.

 

 

 

I chose a site with a minimum of existing growth because I don't want to disturb the area any more than necessary but, because the guava is:

• A) Considered a pernicious invasive that everyone wants to kill anyway, and....
• B) is also a lively and resilient growing machine, that....

..... I start envisioning using the few existing trees as the foundation posts of the structure and extending up to serve as supports for the roof as well. These things are so tough, that I fully expect them to bounce right back, sending out new lateral growth, despite being viciously "topped". And if they die.....well, I was going to cut them down anyway.

 

But what if they DO live? Wouldn't it be cool if the structure was as "alive" as possible? Not only is the guava a vigorous and hardy tree, it's also enthusiastically innosuculate, meaning that it is self-grafting. If you want to weave a living wall, there would be few better choices of plant to begin with.

 

In any event, while I entertain grand thoughts, I also rig a tarp overhead, to keep the tools dry.

 

 

The sumi ink that I'm using for layout works great on damp lumber, but if the stick is actually wet, the ink just runs and bleeds. If I swipe the area with a rag, then lay down a very fine line, the ink will set enough to hold, but it's not the same as say, marking on dry wood. FYI, for those of you working in the rain. Fresh cut green wood, no problem. Compared to pencil, there still is no comparison. A pencil only works well on dry lumber, and it's been nearly 6 months since I've touched one for carpentry. I used one the other day...for about 2 seconds. How the hell do you cut to such a fat f***ing line, haha?!

 

 

 

I also built a new sharpening station.

 

 

Haha.....nice, huh?! I miss using good stones though. My standards are currently low.

 

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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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