A tale of two extremes--- heat treating woes.

Heat treating issues. Here are a couple of fails (Well, one fail, one partial), that may provide some insight into making a laminated blade tool..... And offer another opportunity  for me to abuse some edges!

These blades were: normalized, clay slip coated, water quenched, then tempered at 325°F.

My forge black skin (kuro-kawa?) is looking better, at least.


A slender, curved marking knife.

I made this knife with a rather pronounced curve, to more easily rest in the hand.

The short, steep (around 45°) beveled edge rides nicely along any guide that you happen to use.

I favor wooden try-squares that won't harm bladed tools...... And you can make them whatever size that you need. The only issue is that you need to use a marking knife that won't cut into the blade of the gauge, ergo...



After the water quench the blade warped just a bit, towards the iron side of the blade. The bend at the right is intentional, the very slight gap underneath the tip, to the left, is not.

The warp is about 1/16", but is not something that I want.



This blade was dead flat, prior to quenching. Other, more learned folks can better explain how this works, but essentially, the hardened steel is locked into a crystalline structure that is larger than it is in its soft, annealed state. That means that laminated blades tend to warp away from the steel side, towards the soft iron side.

This blade was easily corrected by carefully hammering it flat, using a good sized hammer, and a stump as an anvil. I say "carefully", but I didn't use THAT much care, really. Just tried not to hit the edges, and checked it continually against a flat reference surface. The hard steel/soft iron combo can be remarkably durable. It didn't make for interesting photos, however.


This blade sharpened up nicely, and proved very hard. It easily resists my hardest file.

The lamination line is instructive. Notice the diffuse border?

I spent too much time working this blade, and it got too hot at least once. Not sparking hot, but definitely a bright orange, welding heat. The fuzzy edge is (I believe) due to carbon migration from the steel, into the iron. While still VERY hard, I would NOT buy a blade that looks like this. I have chisels that have indistinct lamination lines, and they are decidedly softer than my best ones.



Now for the fun one. In a prior post, I mentioned a kuri-kogatana blade that I broke into pieces because it had a failed forge weld. I made this blade in a paired state, meaning that I forged it double length, then cut the blank down the middle, forming two blades. This is the other half, and I thought that it might be salvageable.

Wrong. The blade warped significantly, nearly 1/8".

The fact that it warped 1/8" isn't overly concerning. The WAY that it warped is. This didn't photograph well, but almost the entirity of the warpage is in the last 1" of the blade.

If you zoom in, it's at the point furthest from the camera. My apologies.


After polishing, the cause is revealed.

Not only is the weld of poor quality, the steel also got WAY too thin in one spot. This thin area corresponds to the origin of the bend. It is a toss-up as to which is more deleterious, the poor weld or the too thin steel.


The steel/iron line shows poor definition (I want some of that good, dark, soft iron that they use in Japan!), so I etched the blade with phosphoric acid, to check for carbon migration.

Most of the blades lamination looks fine, with little evidence of carbon migration. It's still a junker, though, so I get to bash it up!


I set the blade, edge up, on the anvil, then smacked it with some mild steel rods that were lying around. I started out with the small stuff, then graduated to the bigger size, hoping for a dramatic failure.

Surprisingly little damage, considering how many (+100), and how hard I was smacking the edge. Look at the notches, hammered into the iron!


I struck the edge over the entire length, but you can see that the damage was most severe in 3 areas. The heel and the tip showed the most damage, but there was significant damage to the area of the bad weld, too.

The steel actually folded over at the heel and toe, indicative of a blade that wasn't fully at its transformation point temperature, before quench. The blade was hot at the center, but too cool at the ends. The edge failure at the weld is due to the steel not having the full support that is provided by the iron.

I want to check the edge deflection, so I pushed the edge (just the steel portion) against the anvil. I was expecting a chip, a crack, something, but got nothing dramatic. The knife easily shaves steel from the corner of my anvil (Fun, but probably shouldn't be a regular test criterion, haha!).

Although the knife is hard enough to shave steel from the anvil, it is not as hard as I was trying to achieve.

Both blades were subjected to the same file treatment. The marking knife was sufficiently hard, showing only a few trace scratches, but the kuri-kogatana tested far too soft. The hard file easily scratched the steel edge, scarcely harder than the Stanley chisels that I used to use.

Blade hardness shouldn't be the sole defining criteria of a good blade. Durability and ease of sharpening are important too. I want all three!

I was surprised that the two blades turned out so dramatically different in hardness. I performed the quench only minutes apart, so you would assume that my ability to gauge color/temperature would have been more consistent. It's not like I did these hours or days apart. I want to heat the tool to juuuuuust above the non-magnetic, to minimize the grain size in the steel. I used a magnet to verify the Curie point, but I obviously wasn't quick enough into the quench bucket.

I also learned that my anvil isn't that hard.

Using the "Point of a sword" knife

Yesterday was just one of those days.....

I seem to be direly lacking in practice, woodworking wise. Things seem to be going quite well and I'm in the groove, but then you offer up the piece at the final fitting...... Too short! Cut a new one....... Even better, but again, too short! It's not quite the old joke "I cut it, and I cut it, but it's still too short!", but it feels pretty damn close.

Working larger pieces (in this case I'm rebuilding our back deck) while trying to maintain close tolerances, is an art unto it's own. I guess that there are two approaches that could be taken.

You can:

1. Cut every piece flat, straight, and true. Every piece is reduced to a common dimension. 
2. " Cut to fit ". Each piece is an entity and construction proceeds in a linear fashion. Fit each piece to the previous one.

I love and admire " Flat, straight, and true ", but this way of building just doesn't work for ME. This is like my imagined ideal. Layout is perfect and exact, joints are simple(er) to cut, and things come out as planned. For this to work, all components must be oversize, to end at the desired dimension, so there often must be huge amounts of waste. It's also a lot of work reducing the stock, so power tools are most often used. This is " Set it and forget it ".

" Cut to fit " is my reality. Each piece is different and must be sculpted to fit the way that you want it. NOTHING is flat, straight or true, so scribing (as opposed to measuring) is the rule. This can work well, but you need the proper mindset. A minimum of material is wasted, but you get tired of walking back and forth, and few corners can be cut. Trying to save time often results in errors further down the road.

I try for a hybrid approach. For small stuff like a cabinet, this works well. You make the case perfectly, then scribe fit it for installation. For bigger stuff it gets more difficult. Boats are all scribe work, while houses are somewhere in the middle. Our house would list heavily towards the scribe end of things.

We are taught to think in terms of "Flat, straight, and true" (FST), and when things don't work out as planned, we get frustrated and confused. When you do enough if this work (say carpentry) you learn a multitude of little tricks that help you accommodate the inevitable inconsistencies. You assume FST, then work the reality. This works great for machines, OK for groups of people, but makes me (the individual) a bit nuts.

It is a mindset thing. I measure, then cut, always anticipating the next step. My mind is centered on a whole, looking at the goal as a finished project, in this case a deck. My attention and energies are diffuse and thinly spread, because I only have so much to invest at any given time. The usual outcome is a finished product that looks acceptable, and a perfect job is one that gets comments like "And you made that by hand? Really?!! It's as good as that one I saw at the store!". My problem is that I am concentrating on being "done", and therefore not fully present. This makes me feel tired. Big projects get delayed, because you are already anticipating how much work something will be, and how tired you will be when it is finished.

Yesterday's work was me falling into the hybrid FST trap. I cut things close, leaving a margin for adjustment, and thinking ahead. Thinking efficiently. Measure, cut, fit, and finish. Offer it up, often in pairs. A very minor thing (like refining a joint to a hair thin line), can cause two pieces to be essentially too short. Because you ALWAYS start with the longest piece, you can reuse the miscut pieces somewhere else, at least. My time (and the energy invested) are gone, but at least I get more practice this way.

If I look at each step as an individual project, I find that I do dramatically better work. I GAIN energy as the project progresses, rather than feel relief at being finished. This change in mindset is such a simple thing, and it alters EVERYTHING. Instead of thinking about the most efficient way of doing something, I try to do this ONE thing well. My tools have never been sharper, and my cuts have never been straighter.

That said.........



The "Point of a sword" knife has leaped up into my top 10 list of "Tools that I didn't know that I needed ". When "Good enough" isn't, and my joints need a little bit of finessing.....it's a little bit like an eraser for wood.

Separate the joint, only enough for access. I can use it one handed, but it's big enough to use with two.

Combined with my favorite kerfing saw.

Best friends forever!


The knife excels at endgrain. The knife coming to a point means that it cuts with a shearing action. The point can access tight areas like corners.

I formed the point on this knife at a 90° angled tip, but a lower angle would be useful for detailed work. I plan on making another style that has a "sharper" point, and has beveled sides like a dovetail chisel (shinogi-nomi)


Here's an easy one. The tongue on this finger joint is crowned slightly (probably from "crowding" the saw and driving it to hard).

Not perfect, but better. If each thing is better than before, after a while they get pretty darn good.



I thought that this knife would maybe be as useful as a paring chisel, but really more of a curiosity. Interesting.........but how often will you really use it, you know? To the contrary, I am finding it to be one of my most used tools. Two handed, you can take very thin,  controlled, shearing cuts. One hand is fixed and provides the anchor/pivot point, while the other gives drive. Or, you can just stab it at the area that needs adjusting, and the wood curls out of the way. The knife cuts with a unique plunge cutting action that is unlike any other tool that I have. A joinery shiv, haha!

The pointed shape of the tip seems to provide balance to the cut, and the flat back helps to keep the cut planar. There is occasionally a tendency for the blade to dive, so perhaps an ultra-flat back isn't necessary. I'm not sure, and am withholding judgment.

This knife was forged from a small piece of old Nicholson file (O-F) steel, forge welded to a larger piece of mild steel (something that my daughter and I dug out of the muck at the marina). Clay slip, water quench,  3 temper cycles at 325°F for 1 hour. The O-F steel is proving very interesting. Very easy to sharpen, it feels very different on the stones than even, say, YSS white steel #2 (a simple 1.00%-1.20% high carbon steel). It sharpens like a soft chisel, but has shown no edge degradation and hasn't needed honing yet, after 4 days of fiddling with Port Orford cedar. Now that I think of it, when sharpening, it feels similar to how carbide sharpened with diamond feels. Carbide is VERY easy to sharpen, if you use diamond.

The knife cuts lightly, but feels toothy somehow (even though I polished the edge using my finest stones), and the edge LOOKS great under the microscope. Weird. I'm curious to see how the edge chips (as it inevitably will).

There is a guy named Murray Carter that makes Japanese style knives professionally. He has an edge sharpness test that he calls the "3 finger" test. Maybe it's 4 fingers, I can't remember, but the gist of it, is that if you touch the edge of a knife using 3 or 4 fingers simultaneously, and your hair kind of stands up in alarm...... That's sharp. It sounds goofy, but it does kind of work and it certainly is an interesting metric. This knife still feels that way, after 4 days of use. I wonder how hard it is? I would guess around Rc60-62, but people terms to overshoot their numbers, so.... It is harder than my hardest file, anyways. What I REALLY want to know is how TOUGH it is.





These are from the tool kit of a Japanese pro.

I wonder why he has 4 sizes? The second from the left (24mm?) looks like it sees a bit more use.


Eye aspire.

Clean. Nice. Candy.

New old kanna, Ura-dashi with a heavy hand, and a gift for a friend

Sometimes my writing skills lead me to despair. I, too have to read this stuff, and so often I feel that I come across as an overly excited 10 year-old (not too far from the truth, I suppose), but what can you do? How do you add emphasis except using caps and exclamation points? Parenthetic thoughts and related diversions........... open ended comments......At least my plodding diction, repetitive verbosity, and closed-eye silent thinking doesn't translate into print.

I'm trying to improve my photos, too. Thank God.




September feels like new/old tool month. Despite already having more tools that I can use (Some I don't even know HOW to use!), the other day I got some more old kanna from Junji (eBay seller yusui). Two are nice ones, but the third needs work..... Not much, but it might be somewhat educational.

The big news that is restructuring our lives, is that my lovely and exceedingly brilliant wife (Renee Bellinger), has accepted a post-doctorate position in Hilo, Hawaii. What I REALLY want to be doing is forging tools, making knives, saya-nomi (chisels specifically shaped for making wooden sheaths) being particularly prominent in my thoughts. Instead, I need to concentrate on making our house less objectionable to it's future renters, so I need to alter my mind-space and address some long unfinished projects. At least it will involve working with wood. Soooooo much to do, poor me..... Moving to Hawaii!!




A jakuri-kanna (groove cutting plane) for plowing the narrowest of grooves. 2 mm width!

This one is a bit unusual. In addition to it being the narrowest that I've seen, the cutting iron has been sharpened at an unusual angle.

Is this angle just the result of inattentive sharpening, or is there a specific intent at work here?


I grab a scrap of wood, to use as a simple guide.

This plane is flush to the left hand side, but otherwise has no adjustable fence (as a jakuri-kanna normally does), so this seems like how things should work. 

The kanna works fine (it was very sharp, as received), and cuts a neat little groove, just a hair over 1/16" wide. 

With two knives shearing the cross grain fibers, the main blade only need to plow out the waste in between. These are some of my favorite planes.


What about the angled blade, though?

This guy can be used tilted, to cut VERY tiny female dovetail grooves. It certainly looks like this was the intention. There are two pieces of pine tracked onto the sole of the plane, acting to stop the cut at 3 mm deep. What was this plane used for? What did this carpenter specialize in?



65 mm width kanna.

It's a quality tool. The dai is decent. It has a very sturdy, copper plated (?!) osae-bo retaining pin.



Both the main blade, and the back blade are laminated (good!), but both bevels have seen some pretty severe attention (bad?). It has the ubiquitous paper shim.

So many of my kanna have paper shims, I'm almost beginning to prefer it that way. Paper makes a great shim, allowing for good blade support AND.....a good feel for adjustment. Grippy, without being too tight. A kanna that has a paper shim is not cause for concern. Not much, anyway.


Both blades are in need of ura-dashi, having been ground back, clear to the hollows.

Nice blades, though.


The edges of both blades have been ground back 2-3 mm. The face of the bevel has seen LOTS of action from the pointed end of a hammer.

Here is a closer look.

Each of these dimples (100's of 'em) was caused by hitting the bevel face with a hammer.


This type to be exact. A funate pattern genno.

Pro Shop Hokuto had lots of great hammers.

What we have here (probably) is a kanna blade that chipped out very badly. The edge has been ground back about 2 mm. The bevel has been hit repeatedly, as part of the normal ura-dashi process, leaving many small dimples on the bevel face. All that remains is to flatten the back of both blades, them match them to each other.


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This is an extreme example of periodic kanna maintenance. If you REALLY use your kanna as a tool, you will eventually chip a blade. Hard knots, unseen gravel, hell..... Clumsy hands dropping a blade during sharpening have probably caused more chips than anything else combined. You grind back the edge until you are in clean metal. Use a dry wheel bench grinder, but don't overheat the blade. Grinders are great tools, just take your time.


Here is a great one that I would love.

A cool running dry wheel on one side, a flat lapping plate on the other side. Charged with green compound for buffing, this would be a very efficient system.

This type of thing is what pros use. They don't dink around with 10 different stones, diamond sprays, etc. A #1000 grit stone, then #5000-#6000 grit....done. Maybe start with a #220 if things are really bad. It is mostly us enthusiasts, that like to bury ourselves in minutia, that turn sharpening into such a difficult process. Ura-dashi is the same way.

I was reading the blog of a professional tool sharpener a while back, and he detailed the process of how he fits a brand new kanna. Often the new blades are warped, and need to be forcefully adjusted. First he grinds the edge back about 4 mm, until the once sharp blade is instead a blunt flat vertical of about 2-3 mm. This is to minimize the likelihood of cracks developing. He puts the blade onto a stump, then wails away, using a sledgehammer. After he gets the blade into the shape that he wants, THEN he does the finer ura-dashi.

You would think that this extreme abuse would cause a blade to shatter, but it doesn't (usually). One of the beauties of the laminated construction is that it is very durable. Don't try this with your A2-cryo-powder-metal-whatever blade.


Ura-dashi is a regular thing, and not that big of a deal. The worst thing that can happen is that you might end up with a blade that needs more attention. Like this one. Use your judgment, take some care, and things will probably be just fine.

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When pressed into place, the main blade is over 1 cm from where it should be.

The edge of the back blade has been ground back too, either due to damage, or just to maintain proper proportions. I can't tell yet for certain.

This kanna needs the ura-dashi process finished. The main blade and the back blade need to be matched. The main blade is now too tight, so the blade bed needs to be adjusted. The sole of the dai is then given a final adjustment, and she should be ready to work. It's a lot of work, but then again, NEW Japanese tools often need all of this done, too. This kanna was $16, if memory serves.



FINALLY......

A seme-ganna, bought as a present for a friend.

A seme-ganna/ seme kanna, whatever, is a very specific type of kanna.

The blade width is only about 24 mm or so. That's 1" for us metrically challenged.



The kanna sole is beveled to either side of the cutting edge. The bevel extends right to the corners of the blade.

The relieved sole allows you to get right into the inside of a chamfered corner. You know how when you use a router to put a chamfer on the inside of a cut-out, there is that little bit where the router can't reach? I do this all the time. I build a cabinet, something with drawers for example, then after it's assembled, I remove the drawer and cut the inside chamfers. These are called masons corners. This kanna will trim the final little bit, right at the intersecting junction.

From the supremely talented Junichi Maeda,  Atelier-M4 blog, 

When I used routers, I had to finish the corners using a chisel. Bye bye routers..... I'll keep the chisels, though.



I know that my friend wanted one of these for his collection, but I need to apologize for its taking so long to send his way.

SURPRISE!