The Story of a Few Steels

An illustration of the Eidai tatara furnace (a cross-section illustration is shown at the end of this article) with human-powered blowers to right and left. Looks like hot work.

The things that will destroy America are prosperity-at-any-price, peace-at-any-price, safety-first instead of duty-first, the love of soft living, and the get-rich-quick theory of life.

Theodore Roosevelt

The terms White Steel and Blue Steel frequently pop up in discussions about Japanese woodworking tools and kitchen knives. The usual misunderstandings abound in those discussions and BS takes majestic wing. In this article we will try to share some accurate information sourced directly from the steel manufacturer, ancient blacksmiths that actually make and work these steels, and Japanese professional craftsmen paid to make sawdust using these steels instead of the usual soft-handed shopkeepers and self-proclaimed experts living in their Mom’s basement.

We will begin by studying some etymology of two of Japan’s most famous tool steels. We will then drop into history class to discuss ancient domestic Japanese steel, and then shift our attention to why these modern steels came into being. After that, we will go to metallurgy class, but without the technical jargon, to understand what chemicals these steels contain and why. We will also outline the defining performance characteristics of those same two steels in the case of woodworking tools.

For those who enjoy more technical details combined with pretty pictures, we have concluded with the results of a brief but very informative materials engineering study.

Please ready your BS shovel.

Product Designations: Yellow, White & Blue Label Steels

These terms refer to tool steels manufactured by Hitachi Metals, Ltd. in their plant located in Yasugi City in Shimane Prefecture, Japan. If you are into woodworking tools or Japanese cutlery you have heard of these steels.

Hitachi, Ltd., founded in 1910, is one of Japan’s most prestigious manufacturers. Its subsidiary, Hitachi Metals, Ltd., was established in 1956 primarily through acquisitions.

“White Steel” is an abbreviated translation of HML’s nomenclature of “Shirogamiko” 白紙鋼, which directly translates to “White Paper Steel.” Likewise, “Blue Steel” is an abbreviation of “Blue Label Steel,” the translation of “Aogamiko” 青紙鋼.

Just as “Johnnie Walker Blue” is the commercial designation of a famous Scottish whiskey with a blue label pasted onto the bottle, Aogami is the designation of a high-carbon tool steel with a blue-colored paper label pasted onto it. It’s that simple.

While Johnny Walker may be kind sorta yellow, it is definitely not a blue tinted booze much less red. Likewise, the color of Hitachi Metal’s tool steels do not vary in color, only the labels do. If someone tells you they can tell the difference between the two steel by simply looking at them, tell them to give you a nickle and pull the other one.

There are those who insist they can tell the difference between steels by licking them. Some humans are strange.

Since your humble servant can read and write Japanese, I feel foolish calling these materials White Steel or Blue Steel as many in English-speaking countries do, so prefer to call them Yellow Label Steel, White Label Steel or Blue Label Steel in English, or Kigami, Aogami, or Shirogami steel. Please excuse this affectation.

Now let’s go back in time a few hundred years. My tardis is that blue box just over there. A change into period-correct wardrobe will not be necessary, but please turn off your iPhone and try to not embarrass me in front of the locals.

Traditional Japanese Steel: Tamahagane

Tamahagane, written 玉鋼 in Chinese characters, which translates to “Jewel Steel” and pronounced tah/mah/ha/gah/neh, is famous as the steel traditionally used to forge Japanese swords, but prior to the importation of steel from overseas, beginning with products from the Andrews Steel mill in England, it was once used for all steel production in Japan.

Before Admiral Perry’s black ships re-opened the many kingdoms and fiefdoms scattered across the islands that now comprise modern Japan, the only local source for natural iron was a material called Satetsu, a loose surface iron written 砂鉄 in Chinese characters, meaning ”sand iron,” and pronounced sah/teh/tsu. Satetsu looks exactly like black sand. It is quite common throughout the world, as you may discover if you drag a magnet through a sandy river.

Typically found in rivers and estuaries, for many centuries the area around Yasugi City in Shimane Prefecture was a prime source.

Satetsu was historically harvested in Japan using dredges and sluices creating horrendous environmental damage. Fortunately, the days of wholesale estuary destruction are in Japan’s past.

Although Aluminum is the most abundant metal on the third rock from the sun, iron is said to make up 34% of the earth’s mass. Japanese satetsu as harvested is a fairly pure form of iron lacking nearly all the impurities typically found in iron ore from mines.

Historically, satetsu was refined in rather crude furnaces called ” tatara” to form clumps of brittle, excessively-high carbon steel. This technique is not unique to Japan, although many Japanese believe it is.

A tatara furnace in operation. Satetsu is combined with charcoal and heated over several days. The resulting bloom steel, called “Tamahagane,” settles to the bottom in clumps and puddles and is removed by breaking the furnace apart.
出来上がった巨大な鉧を引き出します
The tamahagane that melted to the bottom of the tatara furnace being pulled out of the factory building.
https://story.nakagawa-masashichi.jp/wp-content/uploads/2017/10/tamahagane02.jpg
Freshly-smelted Tamahagane. Being raw iron, it oxidizes quickly.

Steel produced this way in the West is called “bloom steel.” Blacksmiths hammer, fold, and re-hammer these crumbly lumps to remove impurities and reduce/distribute desirable carbon forming the more homogeneous Tamahagane steel. This webpage has some interesting photos of tamahagane.

Related image
A clump of Tamahagane early in the forging process. Most of this material will be lost as waste before a useful piece of steel is born.
This image has an empty alt attribute; its file name is tumi.JPG
After the Blacksmith hammers the raw clumps of Tamahagane hundreds of times, he then forms it into numerous small flat steel patties, which he breaks into the pieces shown in this photo in preparation for forge-welding them into a single larger piece of steel that he can then forge into a blade.

Tatara furnaces are still operated today producing Tamahagane in limited quantities for use by registered sword smiths. Tool blacksmiths use Tamahagane occasionally too out of interest in traditional materials and methods. It is expensive and difficult to work, with lots of waste.

A sawsmith who was active both before and after the availability of British steel on the island of Shikoku in Japan is recorded as saying that imported British steel increased saw production efficiency in his area tenfold. Clearly, Tamahagane was very labor intensive.

Mr. Kosuke Iwasaki, a famous metallurgist and blacksmith, described forging Tamahagane as being like “hammering butter” because it flattened and spread too quickly and unpredictably, at least compared to modern steels.

Besides its peculiar forging characteristics, compared to modern tool steels Tamahagane is a difficult material infamous for being easily ruined and extremely sensitive to temperature during all phases of forging and heat treatment.

In use, tools made from Tamahagane behave differently from modern commercial steel, or so I am told. I own and use a straight razor custom forged from Tamahagane for me many years ago by Mr. Iwasaki. I also own antique Scheffield and German razors, but my Iwasaki razor puts them all to shame in terms of sharpness, edge retention, and ease of sharpening. I also own a couple of antique Tamahagane saws, but I have not used them much, nor have I used Tamahagane chisels, planes or knives, so my experience is limited to this one wickedly sharp little blade.

My beloved Tamahagane cutthroat razor by Iwasaki

Why do I bother Gentle Reader with this story of ancient techniques and obscure products no longer viable? Simply because Tamahagane and the cutting tools and weapons it was once used to produce had a huge practical and cultural influence on both Japanese history and the Japanese people’s attitude towards weapons and cutting tools, in your humble servant’s opinion.

Although imported Western steel served Japan well during its ramp-up to modernity, the memory of the performance of cutting tools made from Tamahagane remained alive in the national memory. Indeed, I am convinced the Japanese people’s love and fear of sharp things is not only psychological but genetic, although I have not seen any studies on the “sharpness gene.” But that is a story I will save for the next time we are enjoying a mug of hot coco together around the iori fire on a moonlit Autumn night. May that evening come soon.

Steel Production in Modern Japan

Enough ancient history. Let’s jump back into the tardis and travel to the late 1950’s so we can shift our focus to more modern steels. No you can’t bring back souvenirs. I don’t care what Doctor Whatsit did with his tardis, we are responsible time travelers and will avoid creating casual conundrums. Besides, the import taxes are pure murder. And please, do be careful no little kids slip inside with you.

When Japan began to mass-produce commercial steel from imported pig iron using modern techniques, the first tool steel made was identical to Western steels, including the impurities. These are still available today as the “SK” series of steels as defined by Japan Industrial Standards (JIS).

Eventually, to satisfy the irrepressible sharpness gene of their domestic customers, Japanese blacksmiths and tool manufacturers pressured Japanese steel companies to develop products with fewer impurities and with performance characteristics approaching traditional Tamahagane.

Rising to the challenge, Hitachi Metals endeavored to replicate the performance of Tamagane using modern smelting techniques and imported pig iron and scrap metal instead of expensive and environmentally unsustainable satetsu.

Ingots of Swedish pig iron

Hitachi purchased and modernized an old steel plant in Yasugi for this purpose. They formulated the best steel they could make using the best pig iron they could find, mostly from Sweden, an area famous for hundreds of years for producing especially pure iron ore. The results were Shirogami Steel (pronounced she/roh/gah/mee/koh 白紙鋼), Aogami Steel (pronounced aoh/gah/mee/koh 青紙鋼), and Kigami Steel (pronounced kee/gah/me/koh and written黄紙鋼) meaning “Yellow Label Steel.” Later, they developed Aogami Super steel (青紙スパー ) and Silver Label Steel (stainless steel). Each of these products are available in various subgroups, each having a unique chemical formulation.

For a time, Hitachi marketed these steels with the “Tamahagane” designation. Problematic, that. Indeed, many saws and knives were stamped “Tamahagane” when these steels were first introduced.

With the increased popularity of Japanese knives overseas, several Japanese manufacturers have once again adopted this problematic practice of naming the steel their products are made from as “Tamahagane” despite being made of common steels and even stainless steels. Because these spurious representations were and continue to be made for the purpose of increasing profits for companies that clearly know better, in your humble servant’s opinion even the stinky label of BS is too good for them.

Caveat emptor baby.

Chemistry

We tend to think of steel as a hard metallic thing, but lo and behold, ’tis a chemical compound.

Few chemicals humans make are absolutely pure, and while White Label, Blue Label, and Yellow Label steels have exceptionally low amounts of undesirable contaminants, they do exist. Dealing with the results of these impurities has been the bane of blacksmiths since the iron age.

The most common undesirable impurities include Phosphorus (reduces ductility, increases brittleness, and messes with heat treating), Silicon (a useful chemical that increases strength, but too much decreases impact resistance), and Sulfur (a demonic chemical that reduces strength, increases brittleness and gleefully promotes warping). Obviously, something must be done about these bad boys.

Some people imagine that, through the Alchemy of Science, impurities are simply “disappeared” from steel during smelting. While some impurities can be eliminated through heat and chemical reactions, it is not possible to reduce the content of those listed above to insignificant levels through smelting alone.

Undesirable chemicals, including those listed above, can be tolerated in steel to some degree because, like arsenic in drinking water and carbon monoxide in air, below certain levels they cause no significant harm. The best solution we have discovered is to reduce the concentration of impurities to acceptable levels by using ore and scrap that contains low levels of impurities to begin with, and constantly test, and reject or dilute the ”pot” as necessary to keep impurities below acceptable levels. This practice is known as “Solution by Dilution.”

White Label steel is plain high-carbon steel without other additives, while Blue Label, Silver Label, and Aogami Super steels have various chemicals added to achieve specific performance criteria. Please see the flowchart below.

Production Flowchart of Yellow Label, White Label, Blue Label, and Super Aogami Steels
A flowchart outlining the manufacturing process

Another technique used to mitigate the negative effects of impurities found in steel ore is to add chemicals to the mix. Chrome, molybdenum, vanadium, tungsten and other chemicals are added to create “high-alloy” steels that can be more predictably forged and heat-treated, are less likely to crack and warp, and will reliably develop useful crystalline structures despite detrimental impurities. Such high-alloy steels can reliably produce useful tools in mass-production situations by untrained labor and with minimal manpower spent on quality control. But regardless of the hype, such chemicals do not improve sharpness or make sharpening easier.

If you look at the table below, you will notice that White Label and Blue Label steels both have the same minute allowable amounts of harmful impurities such as Silicon, Phosphorus, and Sulfur.

The table below is a summary of a few tool steels in Hitachi Metal’s Japanese-language catalogue. A PDF can be found at this LINK.

Chemical Table of White Label, Blue Label and Aogami Super Steels

Product Designation Shirogami 1 (White Label 1)Shirogami 2 (White Label 2)Aogami 1 (Blue Label1)Aogami 2
(Blue 2)
Aogami Super
Carbon1.3~1.4%1.20~1.30%1.30~1.40%1.10~1.20%1.40~1.50%
Silicon0.10~0.200.10~0.200.10~0.200.10~0.200.10~0.20
Manganese0.20~0.300.20~0.300.20~0.300.20~0.300.20~0.30
Phosphorus<0.025<0.025<0.025<0.025<0.025
Sulfur<0.004<0.004<0.004<0.004<0.004
Chrome0.3~0.050.20~0.050.30~0.05
Tungsten1.50~2.001.00~1.502.00~2.50
Molybdenum0.3~0.5
Vanadium
Cobalt
Annealing Temp °C740~770°cooled slowly740~770°cooled slowly750~780°cooled slowly750~780°cooled slowly750~780°cooled slowly
Quench Temp°C760~800°water760~800°water760~830°water or oil760~830°water or oil760~830°water or oil
Tempering Temp°C180~220°air180~220°air160~230°air160~230°air160~230°air
Hardness HRC>60>60>60>60>60
Primary UsagesHighest-quality cutlery, chisels, planesHigh-quality cutlery, chisels, saws, axes, sicklesHighest-quality cutlery,  planes, knivesHigh-quality cutlery, planes, knives,saws, sicklesHigh-quality cutlery,  planes, knives
Chemical Table of White Label and Blue Label steels as well as Aogami Super (this table can be scrolled left~right)

Carbon of course is the element that changes soft iron into hardenable steel, so all five steels listed in the table above contain carbon, but you will notice that White Label No.1 has more carbon than White Label No.2. Likewise, Blue Label No.1 has more carbon than Blue Label No.2.

The greater the carbon content, the harder the steel can be made, but with increased hardness comes increased brittleness, so White Label No.1 is likely to produce a chisel with a harder, more brittle blade than one made of White Label No.2.

Accordingly, White Label No.2 steel makes a wonderful saw, but the plates and teeth of saws forged from White Label No.1 tend to be fragile unless the blacksmith removes excess carbon during forging to improve toughness. This is entirely within the skillset of a skilled blacksmith, and can even occur by accident.

In the case of chisels, plane blades, and kitchen knives intended for professional use, White Label No.1 is the first choice followed by Blue Label No.1 steel.

Where high performance at less cost is required, Blue Label No.1 is often preferred.

With impurities and carbon content the same, the chemical difference between White Label No.1 and Blue Label No. 1 then is the addition of chrome and tungsten, elements which make the steel much easier to heat treat, and reduces warping and cracking, thereby yielding fewer defects with less work. Chrome, and especially tungsten are expensive chemicals that make Blue Label steel costlier than White Label steel, but with easier quality control and fewer rejects, overall production costs are reduced.

All things considered, and this is a critical point to understand, compared to White Label steel, Blue Label steel is easier to use, and more productive despite being a more expensive material. Indeed, many blacksmiths and all mass-producers prefer Blue Label steel over White Label steel, when given a choice, because it is easier to use and more profitable, not because it makes a superior blade.

Many wholesalers and retailers insist that Blue Label steel is superior to White Label steel because it is costlier and contains elements that make it more resistant to wear and abrasion intimating that it will stay sharper longer. To the easily deceived and those who do not follow this blog this may make perfect sense. But when wise Gentle Readers hear this sort of tripe they will know to quickly gird up their loins and take up their BS shovels to keep their heads above the stinky, brown flood.

Wise Gentle Readers who choose blades forged from Blue Label steel will do so because they know that Blue Label steel makes a fine blade at less cost than White Label steel, not because Blue Label steel blades are superior in performance. Moreover, regardless of the steel used, they will always purchase blades forged by blacksmiths that possess the requisite dedication and have mastered the skills and QC procedures necessary to routinely produce high-quality blades from the more temperamental White Label steel. The reasons are made clear in the Technical Example below.

Quenching & Tempering

The process of hardening steel, called “heat treatment,” (in Japanese “netsu shori” 熱処理)is key to making useful tools.

High-alloy steels vary in this regard, but in the case of plain high-carbon steels, the two primary stages (with various intermediate steps we won’t touch on) of heat treatment are called “quenching” and “tempering.”

In the case of quenching, the steel is heated to a specific temperature, maintained at that temperature for a set amount of time, and then plunged into either water or oil, locking the dissolved carbon in the steel into a rigid crystalline structure containing hard carbide particles. After this process the steel is brittle enough to shatter if dropped onto a concrete floor, for instance; Basically useless.

To make the steel useful for tools it needs to go through the next step in the heat-treatment process, called “tempering,” to adjust the rigid crystalline structures created during the quench, losing some carbides, but making the steel less brittle and much tougher.

This is achieved by reheating the steel to a set temperature for a set period of time and then cooling it in a specific way. This heating and cooling process can happen in air (e.g oven), water, oil, or even lead. All that really matters is the temperature curve applied. Every blacksmith has their own preferences and procedures.

With that ridiculously overly-simplified explanation out of the way, let’s next take a gander at the “Quench Temp” row in the table above which indicates the acceptable range of temperatures within which each steel can be quenched (using water or oil) to successfully achieve proper hardness. If quenching is attempted outside these ranges, hardening will fail and the blade may be ruined.

In the case of White Label steel, Gentle Reader will observe that the quenching temperature range is 760~800°C, or 40°C. Please note that this is a very narrow range to both judge and maintain in the case of yellow-hot steel, demanding a sharp, well-trained eye, a good thermometer, proper preparation, and speedy, decisive action, not to mention a good purging of iron pixies from the workplace.

Just to make things worse, even within this allowable range, a shift of temperature too far one way or the other will significantly impact the quality of the resulting crystalline structure, so the actual temperature variation within the recommended quench temp range an excellent blacksmith must aim for is more like ± 10˚C.

In the modern world with uniform gas fires, consistent electric blowers, and reliable infrared thermometers, this target can be hit through training and diligent attention, but not that long ago it was seen as a supernatural achievement

Compare this range of quenching temps to those for Blue Label steel with an acceptable quenching temperature range of 760~830°C, or 70°C of range, a 75% increase over White Label steel. That’s huge.

Let’s next consider the recommended tempering temperatures.

For White Label steel, the tempering temperatures are 180~220°C, or 40°C of range. Blue Label steel’s temperatures are 160~230°C, or 70°C of range, once again, a 75% greater safety margin.

The practical temperature range for quenching and tempering Blue Label steel is still quite narrow, but this increase in the allowable margin of error makes the job a lot easier, making Blue Label Steel much less risky to heat-treat successfully than White Label steel.

Judging and maintaining proper temperatures during forging, quenching and tempering operations is where all blacksmiths, without exception, fail when they first begin working plain high-carbon steel. The guidance of a patient master, time and perseverance are necessary to develop the knack. Experience matters.

I hope this partially brings into focus the challenges these two steels present to the blacksmith.

If you seek greater adventure, please look online to find similar data for many of the popular high-alloy tool steels. Comparing those numbers to White Label steel and Blue Label steel will help you understand why mass-producers of tools, with their lowest-possible-cost mindset, non-existent quality control efforts, and workforce of uneducated peasant farmers instead of trained blacksmiths, prefer them for making the sharpened screwdrivers represented as chisels nowadays.

Warpage & Cracking

A huge advantage of chrome and tungsten additives is that they reduce warping and cracking significantly. This matters because a blacksmith using plain high-carbon steel like White Label steel must anticipate the amount of warpage that will occur during quenching and shape the chisel, knife, or plane blade in the opposite direction so that the blade straightens out when quenched. This exercise requires a lot of experience to get right consistently, making White Label steel steel totally unsuitable for mass-production.

Steel is a magical material. When yellow hot, the carbon is dissolved and moves relatively freely within the iron matrix. Anneal the steel by heating it and then cooling it slowly and the carbon molecules will migrate into relatively isolated clumps with little crystalline structure leaving the steel soft.

But if the steel is heated to the right temperature and suddenly cooled by quenching, the carbon is denied the time and freedom it had during the annealing process, instead becoming locked into the iron matrix forming a hard, rigid crystalline structure. This iron/carbon crystalline structure has a significantly greater volume than pure iron, which is why the blade wants to warp when quenched.

Adding chrome and tungsten and other chemicals reduces this tendency to warp.

Sword blades are an interesting example. A Japanese sword blade is typically shaped either straight or curved towards the cutting edge before quenching, but during quenching the blade warps and curves without encouragement from the blacksmith. The skill and experience required to pre-judge the amount of this warpage and the resulting curvature of the blade, and then compensate while shaping the blade before quenching to achieve the desired curvature post-quench is not something one learns in just a few months or even years.

This image has an empty alt attribute; its file name is IMG_7583-1024x683.jpg
A Japanese swordsmith with a blade made from high-carbon Tamahagane poised for quenching. Notice how straight the blade is. He has invested months of work into this blade to this point and a misjudgment or even bad luck in the next second can waste it all. Not a job for the inexperienced or timid.
Related image
After quenching, the resulting warpage is dramatic, but according to plan. The swordsmith must anticipate this distortion and shape the blade to compensate prior to the quench if he is to avoid unfortunate results. Notice the mud applied to the blade before quenching to control the formation of crystalline structures, achieve differential hardness, and control warping. Tool blacksmiths are faced with the same challenges on a smaller scale but more frequently.

Unlike Tamahagane, however, modern commercial steels containing alloys like chrome and tungsten warp much less, and suffer far fewer shrinkage cracks.

Aogami Super is another steel in the table above. It’s an interesting steel, containing more carbon than both White Label steel and Blue Label steel and a lot more tungsten than regular Blue Label steel. Consequently, it is even more expensive. Aogami Super was originally developed as a high-speed tool steel especially resistant to wear. There are much better steels available for this role now, but Aogami Super is still hanging in there.

But all is not blue bunnies and fairy farts because high-alloy steels have some disadvantages too. 

Those who hype high-alloy steels always praise to the heavens the “wear-resistant” properties Chrome and Tungsten additives afford. When the subject is woodworking handtool blades, however, please understand the meaning of “wear resistance” includes “a bitch to sharpen,” and/or “not very sharp.”

Tungsten makes the steel warp less and expands the heat-treat and tempering temperature ranges significantly leading to fewer defects during production. But the addition of tungsten also produces larger, tougher crystals that simply can’t be made as sharp as White Label No.1, and that makes the blade much more difficult, unpleasant, and time consuming to sharpen, all while wasting more sharpening stone material in the process.

White Label steel has no additives other than carbon. It does not need additives to compensate for or to dilute impurities because its production begins with exceptionally pure pig iron, mostly from Sweden (for many centuries the source of the purest iron in the world), and carefully tested and sorted scrap metal. Both White Label and Blue Label steels, if properly hand-forged and heat treated by an experienced blacksmith with high quality standards, will have many more and much smaller carbide clumps distributed more evenly throughout the iron crystalline matrix producing a ” fine-grained” steel of the sort coveted since ancient times

Nearly all the tool steel available nowadays contains high percentages of scrap metal content. Scrap metal is simply too cost effective to ignore. Careful testing is the key to using scrap metal advantageously.

Performance Differences

Gentle Reader may have found the historical and chemical information presented above interesting, but they do not really answer questions you may have about the performance differences between these steels, and when presented a choice, which one you should purchase. Your humble servant has been asked and answered these questions hundreds of times, and while only you can decide which steel is best for you, I will be so bold as to share with you the viewpoint of the Japanese blacksmith and woodworking professional.

Long story short, in the case of planes and chisels, the typical choices of steel are still White Label No.1, White Label No.2 or Blue Label No.1. These steels will not be available much longer.

If you are dealing with honest blacksmiths and honest/knowledgeable retailers with experience actually using, not just talking about and selling, tools, you will have observed that a specific plane blade, for instance one made from Blue Label steel, will cost less than the same blade made from White Label steel, despite Blue Label steel being a more costly product.

At C&S Tools a 70mm White Label No.1 steel plane blade cost 77% more than one made from Blue Label No.1. This means that the blacksmith’s average cost in terms of his labor (overhead, forging and shaping cost being equal) is also around 77% greater than Blue Label steel, a direct reflection of his potential additional time expenditure due to risk of failure.

White Label steel simply warps and cracks more, but when failure occurs it only becomes apparent after all the work of laminating, forging and shaping are complete. Ruined steel cannot be reliably re-forged or re-used, so all the material and labor costs up to the point of failure are simply wasted like an expectation of non-criminal behavior in a California politician. It is not a material for careless people or newbies. The steel that is, not the politician who is certainly irredeemable.

So if White Label steel blades are riskier to make, with more wastage, and therefore more expensive, what are the performance characteristics that make White Label steel blades a favorite with professional Japanese craftsmen? Two primary reasons: First, properly made White Label steel blades can be made sharper. This makes the craftsman’s work go quicker and more precisely.

Second, properly made White Label steel blades are quicker and more pleasant to sharpen. That sums it up.

To some people, especially those that use edged tools professionally all day long, these differences matter a great deal; To others, not so much.

Is White Label steel worth the extra cost? I think so, but the performance differential is not huge, and only someone with advanced sharpening skills will be able to take full advantage of the difference. For most people on a tight budget, or in the case of woodworking situations where sharpness is not critical, and sharpening speed and pleasure are not driving factors, then a less-expensive Blue Label steel blade is perhaps a better choice. It absolutely makes a fine tool that does a great job of cutting wood.

The Wise Man’s Q&A

Let’s shovel some more BS out of the way by performing the mandatory experiment of taking a high-quality White Label steel blade and a high-quality Blue Label steel blade, sharpening them identically using the best stones and advanced technique, test them to cut some wood, and then consider the answers to the following two important questions:

Question 1: Will the additional sharpness of a White Label steel plane blade create a smoother, shinier finish surface on wood than a Blue Label steel blade?

Answer 1: Definitely no. But since the blade started out a little sharper, it will cut good wood a little better a little longer.

Question 2: In the case where edge-retention, cutting speed, and cutting precision are more important than a shiny finish, which absolutely applies to chisels and knives, will the additional sharpness of a properly made and proficiently sharpened White Label steel blade improve a woodworking tool’s cutting speed, edge-retention, precision and control?

Answer 2: Absolutely yes. On condition that the user possesses the skills to achieve and maintain that extra degree of sharpness. There is a reason sharpening has always been the first essential skill in woodworking.

These are the reasons why we don’t even offer chisels made from Blue Label steel, or even White Label No.2 with its lower-carbon content, and resulting reduced hardness.

But whether plane blade, chisel or knife, a properly forged and heat-treated blade made by an experienced professional blacksmith from simple White Label steel will always be quicker and more pleasant to sharpen than one made of Blue Label steel with its added sticky chrome and hard tungsten. To the professional that has the need for the additional sharpness as well as the skills necessary to produce and maintain it, that’s a difference many find worth the extra cost.

I daresay many of our Beloved Customers agree.

A Technical Example

You may find all this technical stuff a bit obscure, but perhaps an example with pretty pictures will help bring things into focus. Please see this informative article by Niigata Prefecture’s Prefectural Central Technical Support Center. If you input the URL into Google and use the translate feature a decent English-language version can be seen. Some of the key results are copied below.

The steel being tested in the study outlined below is White Label No.2 steel (row 2 on page 4 of the Hitachi catalogue pdf). They heat-treated seven samples and listed the results. In each case, the quench temp varied from 750˚~900˚C (1382˚~1652˚F) in water, but the tempering temp was kept constant at 180˚C (356˚F).

Figure 4 below at 775˚C (1427˚F) shows the best, finest, most uniform crystalline (Austentite) structure. Lower temps are not as good. Higher temps are worse. A 25˚ variation one way or the other made a big difference.

The photographs below tells the story graphically. The white stuff visible in the photographs is Ferrite (iron), while the black stuff is spherical carbide (Cementite). When Ferrite and Cementite meld, a desireable hard crystalline structure called Martensite is formed, although there are several steps in between we will not touch on. This subtle change is the essence of the ancient Mystery of Steel, and the keystone to modern civilization.

Fig.1 shows the steel before quench. Notice how the soft iron Ferrite and spherical carbon Cementite are isolated from each other indicative of little crystalline structure and a soft metal. No significant Martensite is visible.

Fig.1: Pre-heat treat condition of Shirogami No.2 steel.

The table in Fig.2 below shows Vickers Hardness on the vertical axis and quench temperature (with a 20 minute soak) on the horizontal axis. Notice how hardness makes a big jump between 750˚C and 775˚C. This is the sweet spot.

Fig.2: Vickers Hardness vs. Quench Temp

Fig. 3 below shows the crystalline structure at a quench temp in water of 750˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. This is 10˚C below the manufacturer’s recommended quench temp. Notice how the iron Ferrite and spherical carbon Cementite are mixing, forming some gray-colored Martensite, but there are still big lakes of Ferrite visible. Better, but not yet good.

Fig. 3: Quench Temp = 750˚C, 10˚C less than the recommended quench temp

Fig. 4 below shows the crystalline structure at a quench temp in water of 775˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. Notice how the iron Ferrite and spherical carbon Cementite are well-mixed forming pretty grey Martensite, indicating that this is close to the ideal quench and tempering protocol; The sweet spot. The crystalline structure shows few lakes of iron Ferrite or islands of spherical carbon typical of durable, hard, fine-grained steel. A mere 25˚C increase in quench temp has yielded a large improvement.

Fig.4: Quench Temp = 775˚C. Well within the recommended quench temp.

Fig. 5 below shows the crystalline structure at a quench temp in water of 800˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. This is still within the quench temp range recommended by Hitachi. Notice how the Ferrite and spherical carbon Cementite are still fairly well-mixed, but the dark spherical carbon is becoming a bit more isolated from the Ferrite forming more, darker groupings. While the Martensite formed is still quite adequate, the performance of this steel may not be as ideal as that in Fig. 4. Notice also that the hardness of the steel has dropped slightly.

Fig.5: Quench Temp = 800˚C. Max recommended quench temp.

Fig. 6 below shows the crystalline structure at a quench temp in water of 825˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. Notice how the crystalline structure has become less uniform than in Fig 5 after only a 25˚ increase in quenching temp.

Fig.6: Quench Temp = 825˚C. 25˚C greater than the manufacturer’s recommended quench temp. The crystalline structure is clearly inferior to Fig.5

Fig. 7 below shows the crystalline structure at a quench temp in water of 850˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. Once again, only a 25˚ increase in quenching temp has resulted in significant degradation in the uniformity of the crystalline structure as well as reduced hardness.

Fig.7: Quench Temp = 850˚C. The crystalline structure has degraded further.

Fig. 8 below shows the crystalline structure at a quench temp in water of 875˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. Once again, significant degradation in the uniformity of the crystalline structure and loss of Martensite is apparent.

Fig.8: Quench Temp = 875˚C. The crystalline structure has once again degraded further. This result is not acceptable in a quality blade.

Fig. 9 below shows the crystalline structure at a quench temp in water of 900˚C, after a 20 min. soak, followed by tempering at 180˚C for one hour, followed by air cooling. Gentle Reader will notice the many white tissues that have developed in addition to tempered martensite. The fibrous-appearing white stuff is considered retained Austenite, a formation that can later be converted into hard Martensite. Once again, only a 25˚ increase in quenching temp has resulted in significant degradation in the uniformity of the crystalline structure as well as reduced hardness.

Fig.9: Quench Temp = 900˚C. The crystalline structure has obviously become less uniform. Not acceptable.

Clearly, Shirogami No.2 steel can be a very good tool steel, but it is also obvious that it is extremely sensitive to heat-treatment technique, requiring knowledge, experience and care to produce good results.

I hope this discussion has been more helpful than confusing.

YMHOS

A cross-section of the Eidai tatara furnace (also pictured at the top of this article) with human-powered blowers to right and left. The central furnace shows satetsu as the first layer resting on charcoal with the fire below. More layers of satetsu and charcoal are added as the process moves forward. The resulting mass of Tamahagane settles to the bottom of the furnace, but does not drop into what appears to be, but is not, a void below.

YMHOS

If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may my mustache forever smell like Corrosion-X

Relevant Posts

Tool Maintenance: Corrosion Prevention

A Rusted Plane Blade by Hatsukuni. What did it do to deserve such horrible neglect?

“How dull it is to pause, to make an end,
To rust unburnish’d, not to shine in use!
As tho’ to breathe were life!”

Alfred Lord Tennyson, Ulysses

Between damaged tools and guns, corrosion prevention has been a high priority for your humble servant over the years motivating me to purchase many corrosion-prevention products and test them in various climates. After climbing mountains of hype and swimming floods of BS I think at last I have something of value, perhaps even the genuine article, to share with Gentle Readers.

There are three aspects of corrosion prevention for steel tools we will address in this article: Corrosion due to sharpening, corrosion due to handling, and corrosion due to storage.

But first, to help Gentle Reader understand the basis for the measures I will recommend below, allow me to explain my sharpening philosophy.

Tool Philosophy

The word “philosophy” is of Greek origin and means the “love of wisdom.” I won’t flatter myself that I developed any original wisdom about maintaining tools, because the truth is I stole most of what I know from better men and the rest came ipso facto from my own screw-ups. Embarrassment is a fine teacher.

Professional craftsmen have no choice but to constantly maintain and repair the tools of their trade, but necessary or no, clients and employers often resent the time craftsmen they hire spend maintaining tools during the work day. After all, they are paying them to make a product, not to fiddle with tools. The perceptive craftsman will strive to understand his Client’s perspective if he wants to be trusted with profitable repeat work.

Therefore, I don’t sharpen, fettle, or repair my tools at the jobsite anymore than is absolutely necessary, and never in front of the Client or employer. This is not some feel-good yuppy-zen BS, but a serious, concrete work philosophy with physical and financial consequences. It was taught to me by experienced craftsmen in America and Japan, all since retired to the big lumberyard in the sky, who knew what they were about. It has served me well.

So how do I keep working when blades dull, planes stop shaving, power tools stop spinning and bits stop biting? Whenever possible I have multiple saws, planes and chisels in the types/sizes critical for that day’s work, and even extra bits and power tools on-hand, so that if a particular chisel or plane becomes too dull to get the job done, or a bit breaks, or a circular saw, for instance, goes tits-up, I need only pause work long enough to retrieve a sharp, ready to rock-n-roll replacement from my toolbox or tool bag.

This means I must purchase, sharpen, fettle and carry around more tools than I am likely to use during that workday. But since my tools are partners that earn their keep, it is not wasted money or effort. In fact, this philosophy has resulted in tool-maintenance habits that I believe ultimately save me time and money while improving my work efficiency all while reinforcing my Client’s or employer’s confidence in me, just as the old boys said they would.

Of course, after a few days of continuous work I will have accumulated multiple blades that need sharpening, so if I am to keep making sawdust I must sharpen them in batches of 5~10 at a time. And because I sharpen in batches, as do professional sharpeners, I have given great thought over the years to maximizing positive results such as speed, sharpness achieved, and economical use of stones while minimizing negative results such as rusted steel. I humbly encourage Gentle Readers to give these matters just a few seconds of consideration. What have you got to lose besides steel?

Corrosion Prevention: Wet Sharpening

The bevel of the Hatsukuni blade shown above. Lovely colors.

The corrosion risk to tools when sharpening is corrosion caused by residual water in the scratches, cracks and crevices of the blade, as well as accumulated chlorine from tap water, promoting rust, especially at the very thin cutting edge. Yes, that’s right, I’m more worried about corrosion dulling the cutting edge than of it creating red spots elsewhere on the blade.

When sharpening a batch of blades in my workshop, after a blade is done on the final finish stone, I dry it with a clean paper towel, apply a few drops of Corrosion Block, smear it around on the blade to ensure a complete coating, and set it aside to draw water out of the pores and seal the steel. It works.

Corrosion-X is another good, but stinkier, product. Neither is good enough long-term, however.

After the blades have sat for a while, usually at the conclusion of the batch, I wipe off the CB and apply CRC 3-36. This is a paraffin-based corrosion preventative that floats out water. Paraffin won’t evaporate or wick-off and is the best product I have found to prevent rust developing on a clean, moisture-free surface.

CRC 3-36 sprays on easily and soaks into everything, and if allowed to dry, will give good long-term protection, as in years. It’s especially good for saw blades because it gets deep into the teeth. But you don’t want to apply it to anything even a little wet with water because paraffin will seal it in promoting rust. Ergo, Corrosion Block first.

There are many rust-prevention products on the market, so I am not suggesting CRC3-36 is the best, only the one I prefer, partly because O Mistress of the Blue Horizons doesn’t object to the smell too strongly if it wafts into her holy chambers from the workshop. If I use Corrosion-X, however, she bars the door with a broom, bayonet fixed, and makes me strip before she’ll let me back into the house. A gentle flower, indeed. But I digress.

This system works fine for short-term, and even for long-term storage if I wrap the tool in newspaper or plastic to protect the coating.

When sharpening in the field, or if I will be using the tool right away, I don’t bother with spray products, but just strop the blade on a clean cloth or the palm of my hand to generate friction heat, apply some oil from my oilpot, and call it good.

If you don’t own and use an oilpot already I won’t call you an idiot, but I still remember the time long ago when that word was directed at me by someone I respected for not making and using one. He was right.

A useful trick I learned from sword sharpeners is to use chlorine-free, slightly alkaline water for sharpening. I mix Borax powder with distilled water in a plastic lab bottle to use to keep stones wet and to wash blades when sharpening. Washing soda works too. A little lye added to sharpening water will also increase its pH. Using such water will not entirely prevent corrosion, but it certainly slows it way down. Test it for yourself.

Corrosion Prevention: Handling

We sometimes pull out a chisel, saw, or plane blade to gaze upon it. They are lovely creatures, after all. There are two things to be aware of when doing this, however.

Recall that the adult human body is comprised of approximately 60% water, some of which is constantly leaking out of our skins mixed with oils and salts. When you touch bare steel with your hands, skin oils, sweat, and the salt contained in sweat stick to the steel and will cause rust. It’s only a matter of how quickly and deeply.

The solution is to avoid touching bare steel you will later store away with bare fingers, and if you do touch the blade, wipe it clean and apply some oil from your oilpot or spray can right away before returning it to storage.

Gentle Reader may be unaware, but there can be no doubt that harsh words not only hurt the tender feelings of quality tools, but can directly damage them. How do I know that rude language offends steel tools, you say? Well, I have ears don’t I? In addition, over the years I learned a thing or two from professional Japanese sword sharpeners and evaluators, who are even more obsessed with rust than your paranoid humble servant, no doubt because of the high financial and historical costs of corrosion in rare and expensive antique weapons.

With the gift to the entire world of the Wuhan Virus from the Chinese Communist Party, we have all become more aware of the human tendency to constantly spew droplets of bodily fluids, often containing nasty bugs, into the air around us sometimes with unpleasant consequences. A handsaw can’t catch the Commie Flu, but fine droplets may find their way to the steel surface when we talk to them or around them. Corrosion ensues.

In Japan it is considered rude to speak when holding a bare sword. Indeed, it is SOP to require viewers who will get close to a bare blade to place a piece of clean paper between their teeth to confirm the mouth is indeed closed and not spewing droplets of spit onto the blade.

I am not exaggerating the cumulative long-term damage fingerprints and moisture droplets expelled from human mouths and noses cause to steel objects. Any museum curator can confirm.

How does this all apply to woodworking tools? If Gentle Reader takes a tool out of storage and either talks to it, or to humans around it, please wipe it clean, apply oil, and rewrap it unless you will be using it immediately.

Tools deserve respect. Perhaps I’m superstitious, but I’m convinced that if we avoid rudely smearing salty sweat or spraying globs of spittle that would cause our tools to turn red and go away, they in turn will be less inclined to cause us to leak red sticky stuff. Some tools are vindictive if offended, donchano.

Corrosion Prevention: Storage

The air on earth contains dust and moisture. Dust often contains abrasive particles harder than steel as well as salts and other corrosive chemicals. We must keep these particles and chemicals away from our tools.

Air also contains moisture that, given access and a temperature differential, can condense on steel tool blades causing condensation rust.

Your humble servant discussed these matters in length in earlier articles about toolchests, but a critical criteria of proper storage is to prevent dust from landing on tools, and to prevent the tools from exposure to airborne moisture and temperature differentials. A closed, tightly sealed, clean container, cabinet, toolchest or toolbox is better for tool storage than pegboards or shelves.

If Gentle Reader does not already have such a tool container of some sort, I urge you to procure or make one.

Tool Rolls

Your humble servant owns and uses tool rolls. They are handy for transporting tools such as chisels, files rasps and saws, but they have limitations Gentle Readers need to be aware of.

The first problem with tool rolls is that they appear to protect the cutting edges of chisels and saws, but that is only wishful thinking because the delicate and dangerous cutting edges are only hidden behind a thin layer of cotton or leather. Guess what happens if you drop a cloth tool roll of sharp chisels onto a concrete slab.

If you bump a tool roll of chisels against another tool, then brush your hand against the now exposed but hidden cutting edges while digging in your toolbox, sticky red stuff may get everywhere. Will the bloodshed never end!?

Do tool rolls protect tools against corrosion? No, in fact they can make it much worse because fibers in contact with steel, especially organic fibers such as cotton, can wick moisture to the steel producing corrosion. Please see the photos above.

Leather tool rolls can be especially bad in some cases because of residual tanning chemicals.

I’m not saying don’t use tool rolls, only to be aware of their limitations and use them wisely.

As mentioned above, I do use tool rolls in the field. The trick to preventing rusted blades is to insulate them from the fabric, so I make little plastic liners from the hard but flexible plastic used for theft-proof retail product packaging that fit into the pockets. Just a strip of plastic cut wide enough to fit into the pocket tightly and folded in half. Besides preventing rusty blades (the crowns will still rust) these little liners make it much faster and easier to insert blades into the pockets without cutting the tool roll. They also help prevent blades from cutting through the cloth or leather. The price is right too.

If you need to use tool rolls for long-term storage, I recommend you clean the tools, coat them with a paraffin-based rust-prevention product, and wrap them full-length in plastic wrap before inserting them into the tool roll’s plastic-lined pockets.

If tools are faithful and profitable servants, indeed extensions of our hands and minds, don’t they deserve more from us while they are in our custody than a rusty, pitted, neglected ruin like the plane blade pictured above?

YMHOS

If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may crickets be my only friends.

Our erstwhile apprentice from the clothing-optional workshop has dropped a chisel into the water while sharpening it, and laments the inevitable corrosion. Being bald as a bowling ball, I’m desperately jealous of her long, curly tresses, but it must get in the way when working on the stones.

The Essential Oilpot

The Japanese Gennou & Handle Part 18 – Wood Selection

Stanley “Stan the Man” Musial, one of baseball’s greatest players and most consistent hitters.

Used to be that bats had thick handles and a big barrel. Then they found it’s not the size of the bat that gets the home run – it’s the speed with which you can swing it.

I think I had the smallest handle around. When I got my bats, I even trimmed them down. I used to scrape them. Some years later when I started getting older, I used to start with a 33 and in the summer it got down to 31 and then probably in September got down to 30.

Stan Musial

In the previous 6 posts in this series we guided Gentle Reader in creating a drawing of a high-performance, minimalist handle to fit your gennou head and body closely. 

The handle in this drawing may not fit your body and the way you work perfectly at first; It may require adjustment, but it is a good place to start. 

Keep this drawing so you can remember what you based the original design on to help you analyze and record improvements for your next new-and-improved handle.

With the initial design complete and recorded in your drawing, the next step in this epic adventure of love, lust and sawdust is to select a stick of wood. Oh joy!

Your humble servant will not be so forward as to recommend a specific wood Gentle Reader should use. Instead, I will examine some performance criteria worthy of consideration, and only then suggest some potential candidate species.

The quotes above by Stan the Man Musial, a famous baseball player and coach that made a career swinging wood fast and with great precision, are especially relevant to the subject of gennou handles.

Please remember that, just like a baseball bat, a slender handle will not endure unless it is made from the right wood and designed to handle the forces it will encounter.

Strength & Toughness

Hammer handles are subject to relatively high impact forces in use which produce stresses and vibration, so the wood must be not only strong, as in resistant to compression, tension and bending forces, but tough. It must also have properly oriented grain.

Softer woods are easy to work and feel good in the hand, but a tenon made from a soft wood such as pine, cedar, poplar or maybe even cherry, for example, will often loosen quickly as thousands of impact forces over time crush the cells.

In addition, since the fit between tenon and eye must be very tight indeed, the process of driving the tenon into the eye will not be easy. Your humble servant has broken more than one handle while attempting this. The last instance was a few years ago with a gennou handle I made from Chinese Mulberry, a wood cherished in Japan for fine cabinetry work and of which I am unreasonably fond due to it’s dramatic grain, its golden color when freshly cut, and the purplish-brown color it changes to over time. I knew it might be too weak for the job, but tried anyway. A sad waste of time and beautiful wood.

BTW, if you have the opportunity to use mulberry wood for cabinet or joinery work, by all means give it a try. I think you will be pleasantly surprised especially as the item made from the wood ages.

Chinese Mulberry Wood

The material you ultimately select must be both strong and tough, but it is important to understand the difference between strength and toughness when considering materials.

The term “tough” in engineering circles means a material has the ability to absorb energy and/or forces without permanently deforming or breaking. A tough wood will still deform and bend, but when the forces that caused it to deform/bend are removed, it will return to its original shape instead of being permanently bent or breaking. In the case of a handle, if it is tough, it will flex somewhat without rupturing.

Gentle Readers are, without exception, highly intelligent with a refined eye and therefore will of course be tempted to use beautiful, dark exotic hardwoods such as ebony, rosewood, bubinga, wenge, kingwood, snakewood, etc.. These are fine woods that make beautiful handles, but I don’t recommend them for a first handle due to their high cost and the likelihood that Gentle Readers will want to replace the first handle they make, and maybe even the second and third, as their skills and understanding of the ideal handle for their body and working style improves with time and experience.

And while they may have beautiful color, sexy figure, and great compressive strength, many exotic woods like ebony and rosewood may lack adequate toughness in some (but not all) cases, and crack easily. And the extra weight of such dense woods is seldom an advantage.

Your humble servant has used them successfully, and so won’t suggest they can’t make fine handles, but simply urge Gentle Reader to be cognizant of the higher risk of failure. If you choose to use an exotic hardwood, please be especially careful of runout, a subject we will discuss below.

Friction

If you consider the vibration and angular acceleration forces acting on the gennou’s head and handle, you will understand the wisdom of choosing a wood that has a high coefficient of friction. Take my word that it is embarrassing to have the head slip off the handle mid-stroke even if no one is watching.

Oily woods like teak lack adequate friction to keep head and handle attached, in my experience. Bocote is another wood that tends to allow Murphy to slip the head off and create unplanned openings in gypboard walls. (ツ)

Stability

Another important performance criteria to consider when selecting a species of wood is that it be stable and exhibit minimal expansion/contraction with humidity changes.

If a wood that forms the tenon connecting handle to head shrinks too much when the ambient humidity decreases, the head will of course loosen.

If the tenon swells too much when ambient humidity increases, the wood cells may be crushed inside the unblinking steel eye causing the tenon to lose the ability to spring back to its original dimensions when humidity again increases, eventually resulting in a loose head. To make matters worse, the handle will loosen up even more when the humidity drops again. Murphy does backwards somersaults and clicks his horny heels at the apex while cackling with demented glee when this occurs.

This detrimental plastic deformation is the big downside to kigoroshi in hardwoods. Let he who has ears to hear take notice.

I encourage you to use a wood with a low tangential/radial expansion/contraction ratio.

The traditional way to deal with tangential/radial expansion/contraction in tool handles such as hammers and axes is to orient the rings of winter wood in the tenon in the long axis of the hammer head/eye. I don’t think this matters much with small hammers with small eyes, but it can make a difference in larger hammer heads with long eyes.

Limb Wood

It is tempting to use limb wood or orchard trimmings to make handles, especially if the grain’s curvature matches the intended design. And leaving some of the natural bark in the grip area can be interesting too. In fact, there was a period a few years back here in Japan when, probably due to the kezuroukai effect, many people were making handles from Mountain Cherry wood with the dark red bark left attached in the grip area.

This is a grand idea, especially if it means you can procure good wood for free. But for heaven’s sake don’t use such wood until it is well-seasoned and stable or you may find your wall has a new dent and your bench dog and his fleas have fled, or your bench cat starts muttering to the iron pixies skulking in your shop about your parentage and the size of the bus you rode to elementary school. Cats are like that, you know.

Wood Grain and Runout

Grain runout is an important factor to take into account when selecting a piece of wood for a handle. A good definition of runout is as follows:

“Runout refers to the orientation of wood cells being other than parallel to the edge (face) of the board. Often difficult to detect visually, severe runout can be detrimental to strength and resistance to vibration and impact forces.”

When a board’s annual rings do not remain within the boundaries of a given pattern, be it straight or curved, the locations where the grain exits the pattern’s boundaries are called “runout.” This is an engineering term used in structural design that is applicable to selecting handle wood. In this case, it has nothing to do with the rotation of wheels and gears. Cracks tend to begin at runout locations and propagate quickly. Excessive runout can significantly reduce the ultimate strength of a board, especially when subjected to the impacts and bending forces of the sort tool handles experience. 

There are those who will dispute this structural reality, but they have done neither the engineering studies nor the destructive testing that would give their opinions value, and are herewith directed to proceed posthaste to a pharmacy to procure the salve Mifune Toshiro recommended to the tattooed criminals in the movie “Yojimbo” before educating them about pain.

Whatever wood you use, and this is extremely important, you want the grain runout to be minimal, especially in the tenon and neck. Ideally, the grain will exhibit zero runout through the tenon and neck and be curved to match the handle shape. In other words, the ideal stick of wood will have a high-percentage of fibers that are continuous from eye to butt. Such wood can be found but it may take time and effort and eye strain to find. Using riven wood is a traditional way to reduce runout and provide maximum strength. On the other hand, some gradual runout in the grip area is usually acceptable.

Here is wisdom: The key to judging runout is to not examine just the board, but more importantly the individual stick of wood you are considering using for a handle after it has been cut into a rectangular cross-section in preparation for layout because, only when you can see all four sides the handle’s entire length, will you be able to reliably judge runout. Murphy will make a fool of you if you let him.

The following link may be informative on the subject of runout: Link 1

Useful Woods

In Japan, the best traditional woods for tool handles are said to be Soraki and Ushikoroshi, both domestic ornamental bushes with white wood and plain-jane grain which are no longer grown commercially and are difficult to obtain. We have a few sticks in-stock for interested parties.

A Hiroki head with a Ushikoroshi wood handle

Nowadays Japanese White Oak is the standard handle wood in Japan. It is denser and stronger and whiter in color than its American and European counterparts, but the grain is quite plain.

Hickory is recognized world-over as the best generally-available material for handles, but it’s grain and color are boring. It should be easy for Gentle Readers to procure since it is sold as replacement tool and axe handles in most hardware and home centers.

Black Persimmon Planks

Other reliable options are Ash, the various species of White Oak, Maple, and Birch, etc..

I have made several handles from Black Persimmon, a fruitwood in the ebony family, yellowish in color but with a dramatic, smoky black grain. Black Persimmon has been highly prized in Japan for hundreds of years as a wood for high-end cabinetry. The grain and color are unique.

Since around 1900, American Persimmon was considered the best wood for golf club heads because of its toughness, the “pop” it gave the ball on impact, and its relative light weight compared to its toughness. It makes a great gennou handle. I am told it is still available in some areas.

A Kosaburo Classic-profile head with a Black Persimmon handle
A Kosaburo Modern-profile head with a Black Persimmon handle

I have also made handles from American Osage Orange, a dense, stringy wood used for bows and musical instruments that makes an extremely good handle, at least once the scary neon orange color mellows through exposure to sunlight. I highly recommend it, especially if you can get it for free, which shouldn’t be too difficult in the US Midwest where it was once used extensively for fenceposts and still grows like weeds around old fence lines.

Just make sure it has reached equilibrium moisture content before making a handle from it.

Top: A 100monme Hiroki Yamakichi head with a new and shockingly-colored American Osage Orange handle. Bottom: A 60monme Kosaburo Classic-profile head with a mellowed American Osage Orange handle.

Maple can make an excellent handle too. I used a stick of highly-figured tiger stripe Maple for the daruma gennou handle below, and another piece of Maple with only a little figure for the smaller daruma gennou further below.

A 80monme Hiroki Daruma head with a tiger maple handle (side view)
A 80monme Hiroki Daruma head with a tiger maple handle (face)
A 60monme Hiroki Daruma head with a tiger maple handle (side view)
A 60monme Hiroki Daruma head with a tiger maple handle (face view)

In the next post in this series we will layout our handle in preparation for making sawdust.

YMHOS

Stan the Man Musial. Please notice the skinny bat he used with great success.

If you have questions or would like to learn more about our tools, please click the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may the angry fleas of a thousand camels infest my armpits.

Previous Posts in The Japanese Gennou & Handle Series

The Strongmen Under the Veranda

Art is born of craftsmen. Art is not born of those called artists.

Tsunekazu Nishioka and Horin Matsuhisa “The Heart of Trees, the Heart of Buddha”

Having worked in architecture and construction in Japan for more than half of my life, your humble servant is fond of Japanese traditional wooden architecture. It has much to recommend it, not only for the visual beauty of the designs and the spacial experiences it often provides, but also the excellence of much of it’s execution, made possible through craftsmen’s skill with Japan’s excellent woodworking tools.

In this post we will examine a few details of Japanese traditional architecture, and the Japanese language phrase one structural member engendered, the origin of which most Japanese are unaware. Perhaps Gentle Readers will find this obscure phrase as interesting as your humble servant does.

The linguistically-intriguing architectural detail that is the primary subject of this article is a wooden structural member called the “en no shita no chikara mochi.”(縁の下の力持ち)which translates to “Strongman under the veranda.”

Some background is called for. As you can see from the photo at the top of this page, traditional wooden Japanese buildings are raised above the surrounding ground by a step or three with an ventilated crawl space beneath the floor. This is a practical feature commonly found in many countries, especially those with high groundwater levels, where it serves to keep soil dampness from penetrating the interior spaces thereby forestalling mold and wood rot.

In Japan, where exterior spaces, such as gardens, landscapes and even celestial spaces (e.g. moon viewing platforms) have been incorporated into buildings, the step up into the building is an important division between interior and exterior spaces. One may wear shoes into the entryway “genkan” of a building, but they must be removed before stepping up and entering the building proper. The genkan, therefore, being behind doors, is both an interior and exterior space. The wooden elevated veranda walkway around the perimeter of the building, called the “engawa” 縁側 in traditional Japanese architecture even moreso.

An engawa veranda in a traditional wooden structure. Notice the step-up from the ground level to the wooden veranda and an additional elevation change when entering the building’s interior with tatami-mat floors. Notice also the worse-for-wear sliding shoji screen doors to the left which separate interior and exterior spaces when closed, but expand the room into the garden when open. Please also notice, if you can, the groove cut into the floor of the veranda near the exterior edge in which lightweight wooden sliding doors called “amado,” meaning “rain doors” slide to enclose and protect the veranda when necessary. To the right of the veranda you can see a gravel-filled drainage trench constructed to receive rainwater dripping from the eaves instead of obtrusive, rudely gurgling rain gutters and pipes. Sitting on fragrant tatami mats, or on the wooden engawa floor with the shoji screens open of a spring evening or autumn afternoon while gazing out at a beautiful garden and listening to the sound of rainwater gently pattering on this gravel is a combination of sensory delights with which I hope Gentle Readers will someday be blessed.
Sorakuen in Kobe, Japan

The floor of the building is supported by a series of beams and purlins called “ Strongmen.” Those at the veranda are called “en no shita no chikaramochi” 縁の下の力持ち meaning “strongmen under the veranda.” In traditional Japanese architecture the veranda structure is designed so that these beams are both cantilevered and partially concealed creating a lightweight feeling, even giving the impression that the veranda floor is almost floating in air when viewed from some angles. The chikaramochi (chee/kah/rah/moh/chee) beams are seldom seen by the building’s residents, but without them, a building could not have a raised floor and would inevitably fail.

A phalanx of noble dragons supporting the first floor of the Taishakuten temple in Tokyo. In traditional Japanese architecture, ordinary uncarved beams supporting the floor in this way are called “En no shita no chikara mochi.”(縁の下の力持ち)which translates to “Strongman under the floor.” In the Japanese tradition, the dragon is a benevolent, noble creature that travels between oceans and heaven. The brackets supported on each dragon’s head in this photo represent clouds, as if the dragon team of strongmen are carrying the building through the heavens. In this case, the dragons have three toes on each foot, indicating that this is a private temple. Only dragons in imperial temples were allowed five toes.
Another noble dragon with waves at his feet and the kumimono clouds on his head. Amazing carving work.

Most Japanese people know and use the idiom without realizing it refers to this structural support.

To refer to someone as being a “Strongman Under the Floor” is to imply they are an “unsung hero,” or a person who quietly, selflessly and competently serves society and others by performing important but unseen tasks as a member of a team. From the Japanese dictionary it means “someone who toils diligently to support others in unseen ways and without recognition.” I salute all the strongmen under the floor, especially in the crafts and construction industry.

In our times we see an increasing trend for people in the public eye, especially actors, artists, musicians, politicians and journalists to display pyrotechnic levels of psychotic narcissism, the less talent and fewer accomplishments possessed the greater their frenzy to attract attention. These foul-mouthed, low-intelligence, often wealthy sociopaths, devoted to self-aggrandizement and the debasement of anything truly admirable, demand not only our unreserved celebration of their psychosis, but compliance with their ever-changing immoral opinions. In situations where individuals with a similar psychosis have managed to grab unlimited power, the resulting loss of innocent life has been horrendous beyond imagining. A former leader of the Soviet Union, himself a remorseless dictator dedicated to the destruction of Western democracies, enslavement of entire nations, and with the blood of millions on his hands once called such narcissists “useful idiots,” and made a science of how to foster and effectively use them to destroy entire nations. His work continues even today.

But while narcissists, sociopaths and their sycophant useful idiots receive all the attention, and sadly, praise, it is the stable, moral, selfless, hard-working common people that build and defend and perpetuate decent societies. In your humble servant’s opinion it is these good people that are the “Strongmen under the floor” that deserve our true respect.

The photos above and below show a happy team of noble three-toed dragons serving as “en no shita no chikara mochi” supporting the first floor of the Taishakuten Buddhist temple in Tokyo. A thankless but important task these several-dozen hand-carved zelkova-wood dragons perform with energetic poise and a toothy grin. Bravo!

{D8E32672-70C5-4FEC-A49A-BAAE900538A2}
A phalanx of noble “strongmen” supporting a lavish veranda. These brave dragons straddle the waves of the oceans below them, and support wooden kumimono brackets which represent the clouds of heaven, on their prickly heads. The symbolism of these intricate carvings and complicated structural details is by no means haphazard.

Many professional woodworkers and blacksmiths are much the same as these dragons: inconspicuous, honest, hard-working, competently supporting the world within their scope without complaint, often with understated style.

YMHOS

The main entry into the Taishakuten temple. The carved figures at the top of the columns facing outwards to the left are Chinese Lions whose job it is to protect the holy precinct from demons and evil spirits. The figure with the elephant-like nose carved into the beam-end facing Gentle Reader is a mythical creature called a “Baku” 貘, a generally benevolent creature that eats bad dreams. The complicated brackets (called “kumimono”) supported on the columns have a structural purpose, of course, but in traditional Buddhist architecture they represent clouds, reflecting the link between the building and the heavens. Can’t have demons, evil spirits or bad dreams nesting up in there! Notice that, while the ends of the kumimono brackets have been painted white, the carved beams and columns are unvarnished, hand-planed, never-sanded Zelkova wood. Counter-intuitive though it may seem, hand-planed wood exposed to the environment lasts longer than if it was finished with abrasives and varnished or painted.

If you have questions or would like to learn more about our tools, please click the see the “Pricelist” link here or at the top of the page and use the “Contact Us” form located immediately below.

Please share your insights and comments with everyone in the form located further below labeled “Leave a Reply.” We aren’t evil Google, fascist facebook, or thuggish Twitter and so won’t sell, share, or profitably “misplace” your information. If I lie may Mama Shishi bite my head off.

Just ask the next baku you meet if it ain’t so. They can’t tell a lie you know.