“Living by faith includes the call to something greater than cowardly self-preservation.”
In this post your humble servant will present a few modern masterpieces of the blacksmith’s art produced recently by a single craftsman. I hope you are as thrilled as I am to know there is at least one craftsman left in the world that can produce chisels of this quality.
The craftsman that made these chisels is very unusual in that, unlike the frantically self-promoting, technically mediocre Hollywood blacksmiths such as Tasai, Funatsu, Kiyohisa, and the modern Chiyozuru gang, he is reclusive and shuns attention. Accordingly, I have been requested to not share any personal details about him, so please don’t ask. The fact is I don’t even know his real name just the brand he uses.
I won’t discuss why he is reclusive, but I will go so far as to say that he is self-employed, well-known in his chosen field, and that chisels are not his primary work product but only a sideline. He makes no more than 5 chisels monthly.
His business philosophy and blacksmithing techniques are interesting so I will share some details about them. He has four strict requirements that a Customer must satisfy before he will accept an order. The first two are business-related, and the last two are about the Customer.
The Blacksmith sets the delivery schedule. Period.
The Blacksmith sets the price. Period
The Customer must be a professional worker in wood who needs and will use the tools the Blacksmith will forge daily. His track record must be independently verifiable. Amateurs and/or hobbyists, regardless of their skill levels, need not apply. Collectors are specifically unwelcome.
Besides being expert in the use of chisels, the Customer must have a minimum level of skills, including the ability to make chisel handles and cut a high-quality Japanese plane block using only hand tools. Once again, this must be verified before an order will be accepted.
Your humble servant commissioned a few chisels from the Blacksmith many years ago and went through this same qualification process, although I didn’t realize it at the time.
The quality of his forging and heat-treat technique is unsurpassed producing a crystalline structure in hard steel that will take an extremely sharp edge, will hold that edge without easily dulling, chipping or rolling while cutting a lot of wood, and is easily sharpened.
But it is his metal shaping and finishing skills that are so awe-inspiring. Please notice the straightness and cleanness of the lines and planes, as well as the uniform and smooth curvature at the shoulders, and perfect symmetry. If Gentle Reader is unimpressed, I encourage you to make a full-scale model from cold wood before trying it in hot metal. I promise you will be convinced.
The Blacksmith uses only “free-forging” techniques, and does not employ the rough shaping dies other modern blacksmiths rely on to improve production speed. His forging technique is so sublime that the entire chisel is shaped to nearly final dimension by fire and hammer, not grinders and belt sanders.
He finishes his products using only hand-powered scrapers (sen) and files.
The performance of Blacksmith’s products are equal to or better than those of Kiyotada back in the day, and are more precisely shaped and more beautifully finished than those of Ichihiro (the Yamazaki Brothers) at their very best. They are simply the best chisels that have been made in Japan in the last 70 years.
Let’s take a look at four chisels recently completed for a Beloved Customer in the USA.
34 x 485mm Anaya Chisel
The Anaya chisel is an antique style used for cutting deep mortises and making other joints in large timbers. It is no longer commercially available.
57 x 485mm Anaya Chisel
42 x 490mm Bachi Nomi
The Bachi nomi is the equivalent to the fishtail chisel in English-speaking countries. The word bachi comes from the splayed tool used to play the 3-string Japanese shamisen, a banjo-type musical instrument. Here is a link to a video of two ladies using shamisen and bachi to perform a famous traditional song in Tokyo.
The Bachi nomi excells at getting into tight places to cut joints with acute internal angles such as the dovetail joints that connect beams to purlins.
There are several ways to resolve the angles at the tool’s face, but in this case the Beloved Customer and Blacksmith agreed on the most difficult, rigid and beautiful solution, the shinogi. This design has the advantage of maintaining a shallower side-bevel angle from cutting edge to neck return providing better clearance in tight dovetail joints.
The handwork performed on this chisel’s face is simply amazing, but the hollow-ground ura is even more spectacular to those who know about this things.
54 x 540mm Sotomaru Incannel Gouge
The Sotomaru or incannel gouge is a strong and convenient chisel used for cutting joints in logs and rounded members on architecture. More information can be found at this link.
This is an especially beautiful example as seen the symmetrical confluence of planes and curves at the shoulders.
I hope Gentle Reader found this post informative. You will never find better examples of the Japanese blacksmith’s art outside of one particular museum. It is exciting to consider that there is still one craftsman alive that can routinely perform this level of work.
While your humble servant has praised these chisels and the blacksmith that made them highly, please do not make the mistake of assuming that I am soliciting orders, or even suggesting that commissioning them is possible, because they are simply not available at any price. Please don’t ask.
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. May my ootsukinomi roll from my workbench and land cutting-edge down on my toes if I lie.
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.
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 your humble unworthy servant will try to share some accurate information sourced directly from the steel manufacturer, ancient blacksmiths that actually work these steels, and Japanese professional craftsmen paid to make sawdust and shavings using these steels instead of the usual soft-handed shopkeepers and self-proclaimed experts pontificating from their Mom’s basement.
We will begin by studying some etymology of two of Japan’s most famous modern 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 most of 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.
There’s much work to be done, so please stretch your muscles and ready your BS shovel.
Product Designations: Yellow, White & Blue and Label Steels
These terms refer to tool steels manufactured by Hitachi Metals, Ltd. (HML) in their plant located in Yasugi City in Shimane Prefecture, Japan. If you are into woodworking tools or Japanese cutlery you have probably heard of them.
Hitachi, Ltd., founded in 1910, is one of Japan’s largest and 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 Paper Steel,” the translation of “Aogamiko” 青紙鋼.
Just as “Johnnie Walker Blue” is the product name of a Scottish whiskey with a blue label pasted onto the bottle, Aogami is the designation of a particular formulation of high-carbon tool steel with a blue-colored paper label pasted onto it by the steel mill. It’s that simple.
While Johnny Walker may be kind sorta yellow in hue, it is definitely not tinted blue anymore than JW Red Label is sangre. Likewise, the color of Hitachi Metal’s tool steels do not vary in color, only their labels do. If someone tells you they can tell the difference between these steels by simply looking at them, tell them to give you a nickle and pull the other one, releasing musical greenhouse gas to entertain the world.
There are those who insist they can tell the difference between steels by licking them. Our feline masters see this as further evidence that some humans are just not right in the head.
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 that product nomenclature and feline psychoanalyses is out of the way, 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 put away your iPhone and try to not embarrass me in front of the locals by holding it over your head and wailing “There’s no signal!!” if you will be so kind.
Traditional Japanese Steel: Tamahagane
Tamahagane, written 玉鋼 in Chinese characters, which translates to “Jewel Steel” and is pronounced tah/mah/ha/gah/neh, is famous as the steel traditionally used to forge Japanese swords, 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 dark sandy river or over a black beach.
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 found 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 problematic impurities typically found in iron ore extracted from mines.
Historically, satetsu was refined in rather crude furnaces called ” tatara” yielding clumps of brittle, excessively-high carbon steel. This “bloomery” technique is not unique to Japan, although many Japanese mistakenly believe it is.
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.
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 on the island of Shikoku in Japan who was active both before and after the availability of British steel is recorded as saying that imported Western steel increased saw production efficiency in his area tenfold. Clearly, Tamahagane was a very labor intensive material.
Mr. Kosuke Iwasaki, a famous Japanese 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. These traits have created a traditional sensitivity among Japanese blacksmiths regarding precise temperature control, a beneficial habit when working the tool steels discussed herein.
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.
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 profoundly influenced both Japan’s 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.
Modern Japanese Tool Steels
Enough ancient history. Let’s jump back into the tardis and travel to the late 1950’s to consider a few modern steels. Yes, you can turn your mobile phone back on once inside, but reception may be poor for a few centuries. 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 causal conundrums. Besides, the import taxes are pure murder. And please, do be careful no little children slip inside with you.
When Japan began to mass-produce commercial steel from imported pig iron using modern techniques, the first standard tool steel produced 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.
Hitachi purchased and modernized an old steel plant in Yasugi City 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 some of these steels with the “Tamahagane” designation. Problematic, that. Indeed, many saws and knives were stamped “Tamahagane” when these steels were first introduced.
With the explosive popularity of Japanese knives overseas, several Japanese manufacturers have once again adopted the deceptive practice of labeling their products as being made from “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.
We tend to think of steel as a hard metallic thing, but lo and behold, ’tis a chemical compound!
Few chemicals humans dabble with are absolutely pure, and while White Label, Blue Label, and Yellow Label steels contain exceptionally low amounts of undesirable contaminants, they do exist. Dealing with the negative impacts of these impurities has been the bane of blacksmiths since the iron age.
The most common undesirable impurities found in commercial iron 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 (a term that’s recently lost nearly all its value through adulteration and profiteering by dishonest “scientists”), 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 either 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
Another technique used to mitigate the negative effects of impurities found in steel ore is to add chemicals such as chrome, molybdenum, vanadium, tungsten to the pot producing “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 unskilled labor and with minimal manpower spent on quality control. But regardless of the hype, such chemicals do not improve sharpness or make sharpening easier. Indeed, the exact opposite is true.
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.
Gentle Reader will notice that White Label and Blue Label steels both have the same minute allowable amounts of impurities such as Silicon, Phosphorus, and Sulfur.
Chemical Table of White Label, Blue Label and Aogami Super Steels
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.
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 reduce 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.
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 an experienced 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 of Japanese professionals followed by Blue Label No.1 steel.
Where high performance at less cost is required, Blue Label No.1 is often preferred.
All things considered, and this is a critical point to understand, compared to White Label steel, Blue Label steel is easier to forge and heat-treat, 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, as a material, 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 nonsense they will know to quickly put on their flippers and floaties in time to keep their heads above the stinky, brown flood of BS about to engulf them.
Wise Beloved Customers 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 forming 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, and not suitable for tools, so further measures are necessary.
The next step in the heat-treatment process is called “tempering,” a process that adjusts 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), 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 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 listed as 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 thorough 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 will aim for is more like ± 10˚C.
In the modern world with easily-controlled 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 performed in the dark of night by wizards. I kid thee not.
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, Hitachi’s recommended 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, such that Blue Label Steel is 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 the discussion this far at least partially brings into focus the challenges these two steels present to the blacksmith.
If you seek greater light and knowledge, 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, minimal quality control efforts, and virtually untrained workforce of peasant farmers, lawn-care professionals and fast-food restaurant workers prefer them for making the sharpened screwdrivers represented as chisels nowadays.
Warping & Cracking
A huge advantage of chrome and tungsten additives is that they reduce warping and cracking significantly. This matters because a blacksmith using a plain high-carbon steel like White Label steel must anticipate the amount of warpage that will occur during quenching, and then 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 totally unsuitable for mass-production.
Steel is a magical material. When yellow hot, the carbon dissolves and disperses relatively freely within the iron matrix. Anneal the steel by heating it and then cooling it slowly and the carbon molecules will migrate and gather 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 rigid 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, and despite the efforts of, the blacksmith. The skill and experience required to accurately anticipate the degree of warpage generated 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.
Unlike Tamahagane, however, modern high-alloy commercial steels contain large amounts of chemicals such as chrome, tungsten, molybdenum, vanadium, etc., with the result that tools made from these steels warp less, and exhibit far fewer shrinkage cracks.
Aogami Super is another HML product listed in the table and flowchart 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 resistant” includes “not very sharp,” and “a bitch to sharpen.”
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, 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.
On the subject of scrap metal, this is not necessarily a negative thing. In fact, nearly all tool steels available nowadays contain high percentages of scrap metal content because it is simply too cost-effective to ignore. Careful sourcing and testing are the keys to using scrap metal advantageously.
I hope Gentle Reader may found the voyage in the tardis, and the chemical information presented above interesting, but it may not have clearly answered your questions 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, your humble servant 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 material.
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 costs being equal) is also around 77% greater than Blue Label steel, a direct reflection of his potential additional time expenditure and material wastage due defects such as cracking or excessive warping. This a constant risk for the blacksmith making professional-grade blades, the mitigation of which he must include in his production costs if he is to continue to keep a roof over his family’s heads.
So the dishonesty of charging more for products forged from Blue Label or Aogami Super steel is repugnant to your humble servant and should be to Beloved Customers too. But I digress.
White Label steel simply warps and cracks more, but when failure occurs it only becomes apparent after all the work of laminating, forging, shaping and quenching 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 honest news from CNN. It is not a material for careless people or newbies.
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?
There are 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. But don’t forget that this additional sharpness is entirely dependent on the user’s sharpening skills and his willingness to maintain his blades to that higher level.
Second, properly made White Label steel blades are quicker and more pleasant to sharpen, making it easier to routinely obtain the extra sharpness mentioned in the previous paragraph. 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 obtainable from 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 wood a little better, a little longer. These results will depend on the skills of the user, of course.
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 and exercises 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, and also possesses 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 the metallurgical technical terms below difficult to follow, 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 may magically appear. Or not. 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, tested their hardness, 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).
The best results can be seen in Figure 4 below at a tempering temperature of 775˚C (1427˚F) producing the 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.
So let’s examine how the crystalline structure changes with different temperatures as seen in the photos below.
The white stuff visible in the photographs is Ferrite (iron), while the black stuff is spherical carbide (Cementite). When Ferrite and Cementite meld, a desirable hard crystalline structure called Martensite is formed, although there are several steps in between we will not touch on. This subtle molecular change is the essence of the ancient Mystery of Steel, and the keystone to modern civilization.
Fig.1 shows the steel before heat treatment begins. 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.
The graph 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 25˚ range is the sweet spot.
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. 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. This organization is typical of durable, hard, fine-grained steel. A mere 25˚C increase in quench temp has yielded a large improvement.
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. 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. 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. This time, a mere 25˚ increase in quenching temp has resulted in significant degradation in the uniformity of the crystalline structure as well as reduced hardness.
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. 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 with some effort. Once again, just a 25˚ increase in quenching temp has resulted in significant degradation in the uniformity of the crystalline structure as well as reduced hardness.
Clearly, Shirogami No.2 steel is a very good tool steel, but it’s sensitivity to heat-treatment technique, and the necessity for knowledge, experience and care in working it are also clear.
What should Gentle Reader take away from this technical presentation?
The first thing to understand is that plain, high-purity, high-carbon steel that has been skillfully forged, quenched and tempered will exhibit the finest, most evenly-distributed hard carbides in a uniform crystalline steel structure mankind can economically produce. Such steel will become sharper than any other metal from which a practical chisel or plane blade can be forged.
This fact has not changed since ancient times, regardless of the hype and marketing of the mass-producers who can at best achieve comparatively mediocre results using modern high-alloy steels.
The second thing to understand is that, while it is not difficult to make high-carbon steel hard, nor to temper it to make a durable product, producing a uniform, durable crystalline structure that will become very sharp, will be especially resistant to dulling, and can be sharpened quickly requires serious skills of the sort that only result from many years of study under a master, and dogged commitment to quality control, especially temperature control and timing.
If steel is the lock, then the crystalline structure the blacksmith creates in high-carbon steel through his skill, diligence and dedication is the key to the Mystery of Steel. It’s a lock and key mankind has been using since ancient times, a combination that is the foundation of our modern, extremely wealthy civilization. But it’s only been a handful of decades since we developed the technology that made it possible to really understand why the key opens the lock. Rejoice, Gentle Reader, for you live in technologically enlightened times!
I hope this discussion has been more helpful than confusing.
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 all my Martensite turn to mush.
I met a traveler from an antique land, Who said—“Two vast and trunkless legs of stone Stand in the desert. . . . Near them, on the sand, Half sunk a shattered visage lies, whose frown, And wrinkled lip, and sneer of cold command, Tell that its sculptor well those passions read Which yet survive, stamped on these lifeless things, The hand that mocked them, and the heart that fed; And on the pedestal, these words appear: My name is Ozymandias, King of Kings; Look on my Works, ye Mighty, and despair! Nothing beside remains. Round the decay Of that colossal Wreck, boundless and bare The lone and level sands stretch far away.”
Here at C&S Tools we frequently use the term “Professional-grade” to describe our products. This is not a “term of art” sculpted from soggy newspaper for marketing purposes, but has an important meaning your humble and obedient servant will break down in this post so there is no confusion among our Beloved Customers and Gentle Readers.
To begin with let’s consider the term “professional.” The dictionary definition of a professional, and the one we intend when we use the word, is a person recognized by his peers as having received a certain amount of intensive, prolonged training and education in his chosen occupation, has achieved some minimum satisfactory level of skill in the performance of that occupation, and is paid for his work and work product. That’s five factors including education, training, skill, occupation, and financial compensation.
We accept as valid the premise that many individuals develop professional-level skills through their diligence and OJT without formal education, training, or qualifications especially in light of the current decrepit state of apprenticeship and training programs in most countries. If they then go on to make a living performing competent work for pay, then they certainly qualify as professionals in our opinion. However, we do not accept the self-aggrandizing theory some put forth that anyone with skill and an artistic flair is a professional even if they aren’t paid for their efforts. Money talks and BS walks.
Woodworking professionals are committed to their trade long-term, and use their skills, time and tools to earn a living by making things for clients, customers or employers in accordance with an agreed-to design, specifications, cost, and schedule, normally formalized in a written contract. Therefore, unlike the talented amateur or hobbyist, the financial and contractual aspects of his job place a professional under constant pressure; If he fails to deliver the promised products consistent with the Client’s requirements and budget on-time he will suffer serious financial and reputational consequences.
By contrast, an amateur woodworker may be skilled and even routinely do museum-quality work, but he has little at risk so tool inefficiency and failure to deliver on-time can only make things unpleasant, not catastrophic.
So what does this have to do with woodworking tools you say? Glad you asked.
While the professional woodworker too must resharpen his chisel and plane blades periodically, the sharper he can make them, the more wood he can cut between sharpenings, and the less time he must spend sharpening his tools, the more time and energy will be available to him to expend each day toward meeting his commitments and getting paid. On the other hand, the blade of a plane, chisel, knife or adze that can’t be made very sharp, dulls quickly, is easily damaged, or takes a long time to sharpen impedes the professional’s work thereby reducing his income and potentially harming his reputation. It is a simple calculation, but one most people, especially amateurs and writers who do not face the same pressures as the professional woodworker, neglect to perform, partly because they are never called upon to assign a monetary value to the time expended sharpening tools, something professionals do everyday when preparing binding bids and cost estimates.
These are by no means new expectations, but in a time when amperage is more important than sharpness, dull blades go into the garbage to be replaced by factory-sharpened new ones, and precision is built-into the machinery used, many professional craftsmen have forgotten them.
The Japanese professional woodworkers I have worked with during my career spanning 45 years have been uncompromising regarding quality and schedule. And they are obsessed with sharpness. It’s in their DNA. This is the same DNA that for millennia have demanded Japanese blacksmiths to always make better, sharper tools.
These blacksmiths and their professional woodworker customers have always been focused on real-world performance above all else. Not reputation or fancy names. Not appearance. Certainly not “mystery.” So what sort of performance should we look for in a “Professional-grade” tool? Very perceptive of you to ask.
Performance Criteria 1: Sharpness
The primary performance criteria of a professional-grade plane, chisel, or handsaw is not how it looks or how much it costs but that it cut extraordinarily well. This high degree of sharpness depends on the following three factors:
1.1 Crystalline Structure of the Steel: The crystalline structure of the blade’s steel is the primary determining factor in sharpness since a blade cannot be made sharper than the carbide crystals exposed at the cutting edge will permit. If the crystals are large, loose and isolated, instead of small, well-supported and evenly distributed, sharpness will suffer. Impurities like sulfur, phosphorus and silica harm crystal formation. Chemicals such as chrome and molybdenum are added to most tool steels nowadays to overcome the negative effects of these impurities, decrease manufacturing costs, and eliminate the need for advanced blacksmithing skills, but an unfortunate side effect of these alloys is their tendency to develop large carbide crystals which reduce sharpness. Consequently, a professional-grade Japanese blade will be made from a pure high-carbon steel like Hitachi Metal’s Shirogami (White-label steel) No.1 and No.2, Aogami (Blue-label steel) No.1 and No.2, or Sweden’s Assab K120 steel. See this post and this post for further explanation.
1.2 Skills of the Blacksmith: The manufacturer of a chisel or plane blade can use the best steel in the world but if he doesn’t have the skills and dogged perseverance to work it properly, the crystalline structure of the finished blade and the degree of sharpness it can achieve will suffer, even if it survives forging and heat treatment. All our blacksmiths, without exception, are masters at using Shirogami No.1 steel, an unusually pure, plain high-carbon steel. Indeed, they have used it every working day over their entire 40~60 year careers. All of them are self-employed and work in their own one-man smithies. Their skills are not suited to mass-production, nor can they be learned in a few weeks or even a few years by factory workers in China, Mexico or Ohio. Feeding materials into a production line won’t cut it.
1.3 Skills of the Sharpener: The finest blade forged by the world’s best blacksmith will become no sharper than the physical skills and diligence of the person who maintains and sharpens it. There are no shortcuts, tricks, books, videos or classes that can transfer those skills through osmosis. I have shared information through the series of 30 articles on this blog that will help, but the end-user must develop the skills in their own eye and hands through their own efforts. Fortunately, anyone with two hands, at least one eye and some determination can obtain professional-level sharpening skills. Please do it.
Performance Criteria 2: Cutting Longevity
A professional-grade tool must remain usefully sharp a relatively long time in order to precisely cut more wood between sharpening sessions. A blade that dulls quickly is inefficient, irritating and makes the workman look lazy. A professional in Japan can’t allow such poor-quality tools a home in his toolbox. This is the most significant difference between Western and Japanese woodworking tools. Two factors govern cutting edge longevity:
2.1 Excellent Crystalline Structure: This factor is directly influenced by Nos 1.1 and 1.2 listed above. A blade with poor crystalline structure will dull quickly and may even fail.
2.2 Hardness: Be not deceived: a blade may have excellent crystalline structure, but if it is soft, it will dull quickly, regardless of marketing claims. The hardness of professional-grade Japanese planes, chisels, kiridashi kogatana knives, and carving chisels should measure in the neighborhood of 65~66 on the Rockwell C scale, as do all our tools. The hardness of Western chisel and plane blades nowadays is typically Rc55~60, with a few going as high as Rc63, the nature of their relatively unsophisticated design making greater hardness likely fatal to the blade. At an average hardness of Rc60~63, consumer-grade Japanese chisels and planes are harder than their Western counterparts, but are still softer than our professional-grade tools. Indeed, the laminated construction and hollow-ground ura of Japanese chisels and planes are features essential to ensure a hard blade will perform reliably even if motivated with a steel hammer.
This extraordinary hardness does however require the user to employ a few professional-grade skills, which is why tools targeting amateurs and for export to markets where consumers typically lack these skills are made softer by design. Indeed, as the number of professional users of planes and chisels has decreased in recent decades, what were once well-respected Japanese tool brands have intentionally reduced the hardness of their blades to avoid warranty issues and appeal to an inexperienced amateur market. These are not bad tools, but neither are they “professional-grade.” What is most concerning is the the way they are marketed, however.
If used, eventually all blades must either be resharpened or replaced. But if a woodworking blade takes a long time to sharpen, if it takes special equipment to sharpen or if it is unpleasant to sharpen, not only is it uneconomical but it will not be loved. Professional-grade Japanese chisels and planes are easily and quickly sharpened despite the hardness of the steel. Indeed, they are a pleasure to sharpen. There are reasons for this:
3.1 Nature of the Steel: Steels that contain alloys such as chrome, molybdenum, vanadium and/ or tungsten are ideal for mass-production by untrained factory workers and are constantly praised in marketing sprays as “ tough” and “abrasion resistant,” but experienced professionals know the real meaning of these phrases is: “a time-wasting pain in the neck to sharpen.” Our blacksmiths do not use such adulterated, uncooperative steels. The blades of professional-grade planes, chisels and knives will ride sharpening stones gladly, can be quickly sharpened, and indeed are a pleasure to sharpen.
3.2 Blade Design – The Ura: A professional-grade Japanese chisel or plane blade has a well-shaped hollow-ground area on the blade called the “ura.” This detail makes it easy to sharpen the extra-hard steel used in our plane and chisel blades while maintaining the ura in a flat plane. The importance of a properly ground ura cannot be overstated.
3.3 Blade Design – Laminated Construction: While extra-hard steel cuts a long time, it can be brittle making a blade fragile, which is why Western chisels, with their homogeneous construction, must be made softer to prevent them from breaking. In professional-grade Japanese chisels, the hard steel cutting layer is skillfully forge-weld laminated by hand to the blade’s body comprised of a softer low-carbon steel or iron called “jigane” that protects the extra-hard steel cutting layer from snapping in half while still being easy to sharpen.
Our blacksmiths do not use inferior pre-laminated steel, despite its convenience and economical advantages.
There are other design and fabrication details characteristic of professional-grade tools which we will not delve into here.
The Amateur and the Professional-grade Tool
Don’t let the discussion above discourage Gentle Reader from using our tools even if you aren’t a professional woodworker because, while tools are terribly vain and frequently gossips, so long as you let them cut wood, they are happy regardless of their Master’s profession. And for those who use chisels, planes and knives for the joy it brings, as I do now, the extra sharpness and edge-retention capability, and the satisfying feeling found sharpening them will increase the pleasure you enjoy when woodworking.
When using professional-grade Japanese woodworking tools, there a few things you should keep in mind. The first thing is that, since their steel is harder than that found in tools intended for amateur use, you mustn’t use them to pry wood, pull nails, chip concrete, or open paint cans. They are not sharpened screwdrivers stamped out in lots of thousands by peasant farmers in Guangzhou, but elite tools born to cut wood. They simply won’t tolerate such amateurish abuse.
The second thing to understand is that you need to learn how to sharpen and maintain them properly. This includes using flat sharpening stones and maintaining a proper bevel angle. More details are available in our Sharpening Series of posts.
If you can show the tools the same respect the blacksmiths that forged them did, then you are well on your way to becoming professional-grade yourself, regardless of your day job. We see it as our duty to help you along that path.
The Future of Professional-Grade Tools
As we look to the future, please note that it is common practice by some manufacturers in Japan to mass-produce chisels and plane blades from inferior materials with mediocre crystalline structure and lesser hardness, but identical in appearance to professional-grade tools, and sell them at high prices to uninformed consumers who are none the wiser. These modern corporations cleverly use dubious marketing techniques that invoke “mystery” and “ancient traditions” when in truth they have replaced traditional materials and techniques with modern mass-production materials and techniques developed during the last 3 decades specifically for mass-producing mediocre-quality, consumer-grade kitchen knives. After all, one can’t tell the quality of a steel blade’s crystalline structure by looking at photographs.
While lower-quality tools purveyed using deceptive marketing strategies will no doubt continue to be profitable for some, our Beloved Customers know how to sharpen and how to properly evaluate a blade. They appreciate honest value more than artful marketing, so we refuse to insult the intelligence of the professionals that are the majority of our clientele through such shabby nonsense.
The demand for professional-grade chisels and planes has decreased dramatically among modern consumers in Japan at the same time those master blacksmiths with the skills and determination to make them are either retiring or moving on to the big lumberyard in the sky. And with the decreased demand for such tools, Hitachi Metals has practically ceased production of Shirogami and Aogami steels. Truly, the strongmen holding up the veranda (縁の下の力持ち）are gradually disappearing.
The future supply off these excellent tools looks bleak, but we hope to continue to be able to provide them to our Beloved Customers for a few more years, God willing and the creek don’t rise.
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.
Just ask the next baku you meet if it ain’t so. They eat nightmares, comfort small children in the dark, and simply can’t tell a lie, you know.