Japanese Handplanes Part 2 : Blade Adjustment

I warn you, if you bore me, I shall take my revenge.

J.R.R. Tolkein

Your most humble and obedient servant has received many requests over the years for explanations about how to setup, adjust, maintain and use Japanese planes. It’s a big subject, enough to fill volumes and volumes, and an important one to woodworkers, but I will try to explain in enough generality that new guys can follow, and in enough detail that professionals may glean something useful.

In this series we will discuss how to adjust a Japanese plane so it works well, how to tune it to increase performance, how to treat the body to reduce warpage and keep it looking good, how to deal with normal wear and tear, how to periodically tap out and dress the ura during sharpening, and of course how to use a Japanese plane.

This last subject is extremely simple but one many amateur users of Japanese planes and most users overseas get wrong. It happens so frequently that I am confident the improvement in Beloved Customer’s personal performance with Japanese planes will improve dramatically from this last subject alone.

The problem with Japanese planes is that, while they are simple tools, they are at the same time more sophisticated than appearances suggests. Dealing with these subtle details without properly understanding them leaves many as confused as a ball of yarn among a dozen big-eyed kittens, so to avoid having too many strands running all over the place, let’s start with the basics, namely how to adjust them. For purposes of this discussion, we will assume our plane is in good fettle to begin with.

Terminology

Your humble servant will not attempt to teach Gentle Readers all the Japanese terms for every part of the hiraganna plane but will try to use standard English language terms wherever possible instead. Indeed, since the plane is a relatively recent tool in the Japanese woodworker’s toolbox, and has a much longer archeological history in the West, it seems silly to use more Japanese words than absolutely necessary to describe something that did not originate in Japan, and can easily be described in English.

I am not a government employee or a legal expert, and so see no need to make things more confusing than necessary. I humbly apologize in advance if this approach offends any purists or employees of the IRS.

The standard handplane in Japan, the one intended to create and/or smooth flat surfaces versus rabbet, chamfer or molding planes, just to name a few, is called the Hiraganna. This word is written 平鉋 in Chinese ideograms and pronounced hee/rah/gahn/nah, without emphasis on any part of the word.

The first character 平 means “flat.”

The second character 鉋 is comprised of two standalone characters combined to make a single character, a common practice in the Japanese language. The one on the left side, 金, means gold or metal, while the one on the right, 包 means “to wrap.”

The character for kanna was not invented in Japan but is said to have been used since the Táng period AD618 – 907 in China, although the tool it represented at the time was a scraper of sorts and not a handplane.

Adjusting Japanese Planes

In order to use a plane of any kind, one must remove the blade to sharpen it, and then re-install the blade and adjust its projection from the body’s mouth to produce a wood shaving of the desired thickness.

Like most wooden-bodied planes, one adjusts a Japanese plane by striking it with a hammer or mallet. To drive the blade further into the wooden body (called a “dai” 台 in Japanese) when installing the blade or when increasing the depth of cut, one taps the head of the blade down into the wooden body. Pretty straightforward. But like most things in life, there are both clever and stupid ways to get even simple jobs done. Let’s consider some of the clever ones, shall we?

The wacky ones can be very entertaining, I know, but I think I’ll leave those for the tool abusers on GooberTube.

Hammer or Mallet

You can use either a metallic hammer or a mallet made of wood, plastic or even rawhide to tap the blade or dai during these operations. They all work just fine, but there are long-term consequences to this selection you need to be aware of.

In Japan a steel hammer is traditionally used by carpenters to adjust planes. Without a doubt it’s convenient and effective, but there are some serious downsides to using a steel hammer you may not realize. Those include:

  1. A steel hammer always mushrooms the blade’s head;
  2. A steel hammer always dings the blade’s pretty face, and most critically;
  3. After many strikes, steel hammers will often crack and even split the wooden body (dai).

A deformed and ugly blade may not be a tragedy, but a split body is an expensive and time-wasting catastrophe, especially if you are a professional that needs his planes to keep cutting.

What did this brightly-polished plane blade do to deserve such barbaric abuse?
All the worst consequences of using a steel hammer on a plane are condensed in this one photo. Notice the mushroomed head of the plane which the owner has probably already ground down several times. We can’t see the blade’s face, but notice how the chipbreaker’s face is all dinged up. And I guarantee you the blade is even more damaged. And of course, the split dai. Tragic! What did this poor innocent little plane do to deserve such barbaric treatment?! And how much of this plane’s useful life did the owner waste?

There may be Gentle Readers who will say: “But I’ve seen Japanese craftsmen using steel hammers to adjust their planes, so it can’t be wrong.” The first part of this observation may be true, but the last bit isn’t. The undeniable truth is that steel hammers have created many ugly, dinged, bent, and mushroomed blades, as well cracked and splintered dai, mostly unnecessarily. Some carpenters are especially abusive of their poor planes, sorry to say, but not all Japanese craftsmen are so inured to the suffering of their tools.

C&S Tool’s planes don’t deserve such violent abuse, so we recommend Beloved Customers use a wooden mallet to adjust them. Without exception. A plastic or rawhide mallet with a wooden handle will work just as well.

Plane Storage

When you purchase a plane, the blade is already installed in the body, although the cutting edge is usually recessed inside the mouth to protect it. The first step, therefore, is to remove the blade and examine it.

If you live in a low humidity area such as Nevada or Arizona in the USA and purchase a plane from a part of the world with high-humidity at times, such as Japan, it is wise to remove the blade and set the plane aside for a few days to let the body become acclimatized, especially if you plan to use the plane in a space with central heating and cooling which may cause the wooden body to shrink in width

If you plan to store your plane for several years in a dry climate, or in a space with central heating and cooling, we recommend you remove the blade and chipbreakers, oil them, wrap them in aluminum foil, and store the body and blades together but without being installed in the body to prevent the blades from restraining the body’s shrinkage causing it to crack. Just to be safe.

Removing the Blade and Chipbreaker

Both the blade and chipbreaker are removed by tapping the chamfered corner of the block behind the blade with a mallet. It is of course possible to loosen the blades by tapping the flat tail end of the block, but there is a risk of striking the bottom edge and deforming the sole. Best avoided altogether.

The physics work best when the mallet impacts are applied in a direction more or less parallel with the blade.

Your humble servant prefers to make this striking chamfer wide to minimize deformation of the body, but this is a personal preference. If your plane’s body is not chamfered, creating it is is an important first step.

The chipbreaker (uragane) must be removed before the blade, but you need to be careful to prevent two unfortunate things from occurring during this process. The first thing to avoid is the chipbreaker jumping out of the block providing Murphy the opportunity for gleeful mischief.

The second thing to avoid is the blade backing out of the body further/faster than the chipbreaker causing the chipbreaker to ride over the extreme cutting edge dulling it. This point is one newbies often overlook until they wonder why the pretty cutting edge they just sharpened is dinged even before they begin cutting.

How does one keep blade and chipbreaker under control? Your humble servant recommends pressing a forefinger onto the chipbreaker and applying pressure upwards when removing it. Do the same on the face of the blade when its turn comes/ as shown in the photos below.

When removing the chipbreaker, apply pressure towards the blade and upwards with your index finger to monitor its movement and help maintain control. It is critical that the chipbreaker moves upward faster the than the blade to prevent the chipbreaker from contacting the sharp cutting edge dinging it.
While applying upward pressure with the index finger on the chipbreaker, tap the chamfer behind the blade to cause the chipbreaker to move up and out of the body’s mouth. BTW, please make it a habit to not strike the center of the chamfer, but instead alternate strikes between the right and left sides of the chamfer to ensure the body will provide long service.

Once the chipbreaker is loose, remove it and go back to tapping the body to loosen the blade further. Continue to apply light pressure to the blade’s face to better monitor the blade’s movement, and to prevent it from jumping out of the body.

The plane used for this example is an extra-wide 80mm finish plane with a blade forged by Yokosaka Masato. The oasaebo steel rod which retains the chipbreaker in-use can be seen tightly installed across the mouth. This is typically never removed over the life of the plane. In the center are the blade and the chipbreaker (uragane). A very nice blade hand-forged from Shirogami No.1 high-carbon steel. To the right is the mallet your humble servant uses for plane adjustments. Notice how the head of the blade is not mushroomed, its pretty face is free of the dents and dings, and the body is free of the dents, cracks and splits that often result from using steel hammers.

Adjusting the Chipbreaker (Uragane)

The chipbreaker is a recent addition to the Japanese plane. In earlier centuries, they had only a single-blade. Unlike the Western Bailey-pattern planes that incorporate the chipbreaker into the linkage necessary to adjust the blade, hiraganna planes work just fine without the chipbreaker. Indeed the chipbreaker’s only role is to reduce tearout, so when tearout is not a concern, removing the chipbreaker will reduce the force necessary to motivate the plane and may even produce a smoother cut.

The chipbreaker of a new plane often needs to be fitted to the blade and body using files and stones, but that is a subject for a future article, so to keep things simple, we will assume the chipbreaker is in good shape and is happily wedded and bedded to its blade.

Gentle Reader is no doubt wondering how to adjust the chipbreaker with the large head of a mallet. The answer is to use the butt of the handle as shown in the photo below. Just hold the mallet’s handle in a fist with the head upward and bring the handle’s butt down on the the chipbreaker. Easy as falling off a log, as my father would say. The connection between the mallet’s head and handle must be quite solid, of course. These mallets are easily made.

Using this technique, your plane blades will look beautiful, and your dai will give many years of reliable service. And although they only have tiny mouths with just a single, shiny, silver tooth, if you look carefully you will sometimes see their clever little smiles.

Using the end of the mallet’s handle to adjust the chipbreaker. Notice that, once again, the index finger is use to monitor the chipbreaker’s movement and to keep it under careful control. To ensure the chipbreaker will do its job, its edge should ultimately be adjusted to be in very close proximity to the cutting edge (>0.002″ (0.05mm). This distance will vary with your plane and the wood being cut, and will require experimentation and fiddling to get right, but with practice, this process will become automatic and intuitive. Be careful to prevent the chipbreaker passing over the cutting edge as this may dull the blade causing Gentle Reader to say undignified things and the iron pixies skulking in your workplace to howl with glee.

To remove or back-out the chipbreaker, one strikes the dai as if loosening the blade, but with a finger on the chipbreaker to keep it from dragging over and perhaps dulling the blade’s cutting edge.

When adjusting the chipbreaker, sometimes the blade will shift position too, so a back and forth adjustment of blade-chipbreaker-blade is sometimes necessary. The tighter the fit of the blade and chipbreaker in the body, the more fiddling is required, so craftsmen such as joiners, sashimonoshi and cabinetmakers that routinely make fine, precise cuts and sharpen frequently tend to prefer thinner blades that fit into the body with less force and are easier to adjust than do carpenters who perform less refined work.

We will delve into this aspect of handplane setup in our journey ass over teakettle down the rabbit hole in a future post.

Adjusting the Blade

In order to take a clean full-width cut, the blade must project from the mouth the appropriate amount, and evenly across its width. In other words, it must not project too far, nor too little, and one corner of the blade must not be projecting more than the opposite corner.

To evaluate the blade’s projection through the plane’s mouth, hold the plane upside down to a light-colored uniform background and look along the plane’s sole. The correct projection will be a thin line of uniform height across the width of the sole. If one side of the blade is projecting more than the opposite side, the blade is either skewed in the body, or it is shaped skewed.

If the blade is skewed, tap the head to the right or left with the mallet. If, however, a few taps fails to make the projection uniform, the blade’s cutting edge must be reshaped.

Please be aware that continued lateral pounding on the blade will not improve the situation and may damage the wooden body.

Most planes allow a little bit of wiggle room for the blade, but sometimes, especially if the body shrinks in width due to reduced ambient humidity, the notches in the side of the mouth may need to be pared slightly deeper, or the blade ground narrower, to provide this right/left wiggle space. Be very careful, however, to avoid paring these grooves more than a thin shaving or two wider because removing wood at the grooves directly and irrevocably weakens the weakest point in the wooden body.

Looking down the sole to ascertain the blade’s projection, the black line visible at the top of this photo. A light-colored, uniform background is helpful for this. In this case, two adjustments are necessary. The first problem is that the blade is projecting too far. This is easily resolved by tapping the chamfer behind the blade, something that, with practice, can be done while the plane is held upside-down in this position. The second problem that must be resolved is the skew evidenced by the blade’s projection being much greater on the left side of the photograph.
Adjusting a skewed blade by tapping the blade’s head laterally. If a few taps will not correct a skewed blade, it probably needs to be reshaped to correct a skew that developed during sharpening.
A much smaller, useful projection with just a tiny bit of residual skew that must be corrected. When taking extremely fine finish cuts, the ability to determine the blade’s projection sometime seems more clairvoyant than simply optical.

To test the projection of the blade, and ensure skew has been removed, hold a a short, narrow piece of softwood such as pine or cedar in your hand and run it over the cutting edge, first on one side of the blade, then the opposite side, and finally the center, and observe the shavings (if any) produced. They will tell you the truth. Be careful not to shave your fingers unless they have become hairy (ツ).

Even experienced craftsmen betimes become gutted, gobsmacked, and guragura upon discovering their otherwise perfect plane blade has become skewed and is projecting too far on one side to be adjusted for a good cut without resharpening it. Of course, the culprit is almost always pernicious pixies, but a wise Beloved Customer (are there any other kind? Nah!) will be careful to follow Petruchio’s example and tame the skew. And don’t forget to use a hardened stainless steel straightedge to check the blade for square when sharpening.

Striking the Body of the Plane

Your humble servant does not want to seem repetitious, but just so there is no confusion, I feel compelled to review a point or two before we end this discussion.

When backing out or removing the blade, make it a habit to strike the chamfered edge of the dai behind the blade alternating between the right and left sides instead of dead-center.

Also, angle your strikes so they are more or less parallel to the long axis of the blade. With a little practice this will become second nature. The reason for this action is simply that it is both more effective and at the same time helps to keep the dai in one piece.

Please, never strike the flat tail end of the plane’s body, but only the chamfered top edge of behind the blade. Too many people who strike the flat end of the tail get carried away and end up damaging the sole.

If you examine your plane you will notice that there is actually very little wood holding the plane’s body together in the mouth area. Indeed the only continuous wood is at the sides, and it is only as thick as the distance between the bottom of the blade grooves and the exterior sides of the body. Not a lot of meat.

If we strike the body’s tail in the center, the body, being relatively unsupported in this area, must flex creating stresses, sometimes enough to crack, sometimes even enough to split it. This sort of damage is common, but almost entirely avoidable because, if we strike the right and left extremes of chamfered edge behind the blade, stresses will be carried through the stronger sides reducing the chances of cracking and/or splitting the tail. You can feel and even hear the difference if you pay attention.

If you don’t care how your plane looks, and prefer replacing or fixing their wooden bodies instead of using them, by all means disregard this suggestion. You might want to get some extra bubble wrap to keep yourself entertained while the bolt and epoxy repair to your plane’s broken body cures.

Damage to the body or blades of C&S Tool’s planes caused by the incorrect use of metal hammers will void the tool’s warranty.

In the next post in this adventure we will discuss how to modify a Japanese plane’s body to make it easier to use.

And please remember the wise words of the Sage of Possum Lake: “Remember I’m pullin’ for ya–we’re all in this together.”

YMHOS

The end view of an amazing nagadai plane body by Inomoto-san made from a piece of Japanese White Oak combining “Oimasa” grain orientation and the highly-desireable ripple grain. In oimasa orientation, the dense, tough, light-colored medullary rays are oriented towards the sole, making the sole wear slower. Using plain-sawn wood will direct even more of these rays to intersect the sole further reducing wear, but at the same time would increase the tendency of the sole to warp. On the other hand, orienting the annual rings vertically in a “quartersawn” configuration would maximize the body’s stability, but at the same time would cause the sole to wear quicker while making the body less resistant to cracking and splitting. Oimasa orinetation shown in this photo is a compromise intended to reduce warping without reducing strength and to improve the sole’s wear resistance. Ripple-grain white oak is not only more beautiful, it contains more of the harder Winter wood making it both more wear-resistant and more stable than ordinary white oak.

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 plane blade be forever skewed if I lie.

Other Posts in the Japanese Handplane Series:

Four Habits and Three Mysteries

The carpenter dresses his plank, the tongue of his foreplane whistles its wild ascending lisp

Walt Whitman, “Song of Myself,” Leaves of Grass

When working in wood the professional aiming for efficiency must continue the work of accurately cutting or shaving wood just as long as possible without stopping to sharpen his blades too frequently because time spent sharpening is time the primary job isn’t getting done. The wise professional therefore needs chisels, planes and knives with cutting edges that not only become very sharp and cut exceptionally well, but stay sharp a long time. C&S Tools are handmade one at a time by master blacksmiths to meet the expectations of Japanese professional woodworkers for sharpness and edge retention.

Alas, even our tools do not have eternally-sharp cutting edges, and at some point must be resharpened to maintain work efficiency and product quality. The experienced professional craftsman will develop unconscious habits to help him constantly monitor the condition of his blades and the quality of the work being performed. In this post we will examine a few ancient techniques for doing so.

The Four Habits

As the saying goes, “timing is everything.”

If Beloved Customer pays attention, you will discover there is a point where a woodworking tool’s blade still cuts, but its cutting performance begins to drop off. Sensing this point in time is critical because if you continue cutting wood much past this point, not only will the energy needed to motivate the blade increase dramatically, but the quality of the cutting done will quickly deteriorate while the time and stone expenditure necessary to resharpen the blade will increase. That’s three variables in the blade, the work and the craftsman that could be expressed in a pretty graph if one was so inclined, a graph that would have at least one inflection point. Which variable is most important to you?

In most cases, when considered from the viewpoint of a craftsman that uses and sharpens his tools daily, and needs them to be quite sharp, minimizing wasted of time and stones over the years tends to be the governing variable because it costs the most money.

Most woodworkers fail to consider these efficiency variables; They simply keep cutting away until the tool either becomes too difficult to motivate, or it stops doing an acceptable job, then stop work and sharpen the blade. This is normal, but the wise woodworker will focus on minimizing the total time and total cost required to maintain his tools even if it means he must pause work to resharpen his blade well before its performance deteriorates badly.

This sharpening inflection point will vary from blade to blade and job to job because every blade, every piece of wood and and every user are unique. Simply counting strokes is not enough. It takes attention and practice to sense when a blade has reached this point.

The following are some things you should pay attention to, and habits you should develop, to help you identify the sharpening inflection point.

Habit No. 1: Sense Resistance Forces: As you use a tool, a plane, chisel, or saw for instance, tune your senses to detect the point at which the blade becomes more difficult to motivate. As the blade dulls, the force that you must apply to the tool to keep it cutting will gradually increase. This is especially noticeable when planing and sawing. Develop the habit of paying attention to this force so you can determine when it is time to resharpen. Your humble servant recommends you regularly use an oilpot to ensure any increased resistance is due to a dulled blade and not increased friction between the tool and the wood;

Habit No.2: Listen to the Music: Pay attention to the tool’s song. That’s right, turn off the radio and CD player and listen to the music your blades make instead. If you do, you will notice that each tool sings its own song, one that varies with the wood, the cut, and the condition of the blade. Is the blade singing, lisping, or croaking as it chews wood? Is it a saw with a basso profundo voice, or a mortise chisel with vibrant tenor tones, or perhaps a soprano finishing plane singing a woody aria? A sharp blade makes a clearer, happier sound when cutting or shaving wood than a dull one does. Learn the happy song it sings when it’s sharp and the sad noise it makes when it’s dull, and all the changing tones in between. If you have ears to hear, it will tell you what kind of job it is doing and when the time has come to resharpen it;

Habit No.3: Eyeball Cuts: Watch the tool and the wood it has cut. Is your chisel cutting cleanly, or is it crushing the wood cells? A sharp chisel blade cuts cleaner than a dull one. You can feel and hear the difference. And you can see the difference in both the shavings or chips and the surfaces the tool leaves behind. Don’t be a wood butcher: develop the habit of frequently checking the quality of your cuts. It doesn’t take extra time, and your tools will wiggle with happiness;

Habit No. 4: Feel Surface of the Wood: Is your plane shaving the wood cleanly, or are the surfaces it leaves behind rough with tearout? Develop the habit of running your fingers along the path your plane just cut to sense surface quality. If you detect roughness or tearout, the plane may be out of adjustment, or more likely, the blade is becoming dull. Or maybe you need to skew the blade, change the direction of the cut, or moisten the wood’s surface with a rag dampened with planing fluid (I use water, industrial-grade busthead whiskey, or unicorn wee wee when I can get it). Next, run your hand across the cut your plane just made to detect ridges that may have been created by irregularities or chips in your blade’s cutting edge. Every one of those ridges indicates a small waste of your time and energy and a flaw in the wood. Don’t forget that the top of those ridges contain compressed cells (kigoroshi) that may swell and become even more pronounced with time. This is accomplished with a few swipes of the fingertips along and across the wood between cuts without spending any time.

These techniques are not rocket surgery. They don’t take extra time. They can be applied to any tool all the time. The key is to pay attention. To listen to one’s tools. To watch their work.

Let’s next shift our attention to three of the Mysteries of Woodworking, their potential impacts on mental health, and how to avoid unfashionable wardrobe decisions.

The Mystery of the Tilting Board

To discuss this Mystery, we will call on the services of my old buddy Richard W. (Woody) Woodward. You may remember him from a mystery story in previous article. Yes, it was a near thing, but he has fully recovered from the effects of chugging a 5th of tequila in an emotionally-charged bout of drama over a brittle blade.

Anyway, this mystery goes something like this. Woody is planing a board about the same width as his plane’s blade down to a specific thickness, but for some unfathomable reason, the board ends up thinner on one side of its width than the other. He checks the blade’s projection from the plane’s mouth, but it is absolutely uniform. In fact to make the board the correct thickness he ends up having to tilt the blade to take less of a cut on one side of the board than the other.

Most everyone has experienced this curious and wasteful phenomenon, but because it is not consistent, many never solve the mystery of the tilting board, but blame it on Murphy’s antics or Pixie play. But never fear, because the solution is elementary, Dear Watson.

In Habit No. Four listed above, your humble servant mentioned residual “ridges.” Please be aware that these ridges are not only unsightly and may damage applied finishes later, but they can actually keep your plane from cutting shavings of uniform thickness. Think about it.

Let’s assume you are planing a board the same width as your plane blade, but the blade has a tiny chip near the right end of the blade that leaves behind a .0005″ high ridge on the board’s surface. With each subsequent cut using this same blade with the same defect the right side of the plane’s body and likewise its blade will be elevated above the board’s surface by .0005″, while the left hand side, which doesn’t have any ridges for the plane’s sole to ride on, is shaved the normal amount.

Assuming you checked that the blade is projecting from the plane’s mouth the same distance across its entire width, with each pass the surface of the wood becomes tilted, a little high on the right side and a little low on the left, so that instead of a flat surface square to the board’s sides, you have produced a flat surface that is thinner on the left side and thicker on the right. This is no bueno, amigo.

If you detect ridges on a freshly-planed surface, immediately check the blade’s cutting edge by running a fingernail along it’s width. Don’t worry, it won’t dull the blade unless you are also a bricklayer. Your nail will feel the catch and grab of defects too small for your eye to see. A few small ones may make no difference, but on the other hand, they might make a big difference.

With this the Mystery of the Tilting Board, one that has driven many a woodworker to distraction, sometimes even leading to fashion decisions involving stiff, canvas jackets with long sleeves connected to straps and buckles that fasten behind the barking woodworker’s back and even pass under the crotch (decidedly uncomfortable, I assure you), has been solved. Only the Beloved Customers and Gentle Readers of the C&S Tools’s Blog can be assured of avoiding this undignified state. Sadly, all others must be responsible for their own mental health.

The Mystery of the Missing Plan

Here is another mystery of woodworking, one that especially vexes those tender souls new to the calorie-burning fun of dimensioning wood by hand.

Let’s say Woody needs to turn a bunch of twisty, banana-shaped boards into flat, square, precisely dimensioned and cleanly-surfaced drawer fronts, for example. All the adjectives after “banana” in the previous sentence are critical to his project’s success because Woody’s ambitious objective is to make 24 piston-fit drawers. Let’s also assume the wood he uses for each drawer-front is unique in both appearance and warpage. It’s a heck of a lot of wood to cut and with no time to waste, so our erstwhile wood butcher gets out his trusty handplane, sharpens it up, adjusts the blade and chipbreaker, gives it a kiss for luck, and without further delay makes the shavings fly through the air in glorious fashion!

But wait a minute! No matter how much Woody planes, he just can’t seem to make some of the surfaces flat, free of wind and the sides square to the faces. It’s like some kinda frikin moving target! Indeed, eventually he is dismayed to discover some of the edges are getting too thin. What to do, what to do!?

Drama queens typically begin interesting antics at this point, but not so our Beloved Customers who, unlike Woody, are stoic, laconic, intelligent and of course, sharply-dressed, and therefore pause their physical efforts to focus their mental powers on solving this mystery. At this point BC’s benchdog perks up his ears and tucks in his tail in fear of the humming emanating from his master’s ears, his benchcat arches his backs, hisses like a goose, and flees the workshop like his tail is on fire, and the resident pixies frantically hide in the lumberpile to avoid being disrupted by the power they sense radiating outward from BC’s mighty brain.

Of course, the conclusion you eventually arrive at is operator error. After then there is cat urine to deal with…..

Too few people really pay attention when using their tools, focusing too much on the joy of making as many chips or shavings as quickly as possible without a plan. For example, a failure common to many woodworkers is to start planing without first identifying and marking the high spots that must be cut down first, and then areas to be cut down next. In other words, they fail to plan the sequence of the work. The result is that time, steel and sweat is wasted cutting wood that didn’t need to be cut while ignoring wood that did need to be cut. And all for lack of a plan measured with a straightedge or dryline and written on the board with a few strokes or circles of a lumber crayon or carpenter pencil

This mystery too has been known to increase profits of the mental health industry and even (heaven forfend!) fashion decisions involving poorly-tailored canvas jackets with crotch straps. Simply not to be borne!

The Mystery of the Sounding Board

Lastly, we come to perhaps the most frustrating and least-understood of the Mysteries of Woodworking. Not to say there are no other mysteries, because there is always that most ancient of riddles that baffled even the enigmatic Sphinx, one which has been repeated endlessly since before Pharaoh wore papyrus nappies, of why Woody would respond honestly to his wife when she asks him if her new pair of jeans makes her bottom look “simply humongous.” Sadly, this is one mystery upon which your humble servant is unable to shed light because even I do not fully understand the heart of woman.

But I digress. This Mystery is one that torments those badly befuddled souls like friend Woody who, lacking a plan to follow, eyes that see, hands that feel and ears that hear, unwisely assume that the board they are working on is stable simply because it doesn’t walk away from him. Perhaps it is the malevolent influence of pernicious pixies that causes himm to ignore the downward deflection the pressure of their plane unavoidably induces in a warped, unevenly supported board, or in a board being planed on a flimsy or crooked workbench.

This unintentional, indeed unnoticed deflection too often causes the board to escape the cutting blade resulting in hills being raised and valleys remaining low where flat surfaces were required. Of course, this leaves the handplane bitterly dissatisfied because it wanted to do good work too.

But this waste of wood, steel, sweat and goodwill can be avoided because, even if the board isn’t rocking like Zepplin and dear Woody can’t feel the board deflecting away from his plane’s cutting edge, he could detect the change in his plane’s song when it is cutting an unsupported area of a board if he only listened because the board is also a “sounding board.”

Think of all the money saved that Woody would otherwise spend on lithium, Prozac, and small hotel rooms with padded walls to ease his mental anguish if only he had the foresight to make a plan, train his hands and eyes to confirm his tool’s performance, and his ears to listen to what his plane tries to tell him.

The experienced professional will investigate each board, make a plan for his work, mark the plan on the wood, shim the board so it is evenly supported on a flat workbench surface, and sharpen his blade if necessary before making a single cut. Then instead of cutting randomly like a modern artist wielding a paintbrush, he will make each cut intentionally, purposefully, in accordance with his plan to make each cut as efficient as possible.

He will also pay attention to the reaction of the wood and feedback from his tools during each cut. He will use the four habits discussed above, and maybe even a drop or two of unicorn wee wee to limit tearout if his budget allows.

If Beloved Customer doesn’t have a master to give you a dirty look or to box your ears when you impatiently err, you must train yourself. Slow down. Make a plan. Execute the plan. Pay attention, use your senses, and spend the time needed to evaluate progress against the plan. Consider carefully why the work is going well or why it is not. This process will slow the work down at first, but over time it will help you develop good habits and guide you along the path to becoming a master craftsman instead of just the typical woodcutter.

May the gods of handsaws smile upon you always.

YMHOS

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 my straightjacket dig into my crotch.



The Mystery of the Brittle Blade

There are few blessings without a curse hidden inside, nor curses without a whiff of blessing. Like most things, it’s a matter of how you look at it.

Joe Abercrombie, Isern, “A Little Hatred”

In this article your humble servant will seek to unravel for Gentle Reader another aspect of the ancient “Mystery of Steel.”

This story does not begin on a dark Scottish moor, nor on a foggy London night in a drawing room with the door inexplicably locked from the inside concealing bloody mayhem splattered across intricately carved linenfold oak paneling; Rather, it begins in an ordinary woodworking shop. And it goes something like this.

The Brittle Edge

The curtain rises on a humble detached workshop where, unbeknownst to our victim, an erstwhile woodworker we shall call “Woody,” dastardly events are about to unfold (cue the deep, ominous music). It’s really just an old dilapidated garage, but it’s Woody’s kingdom and he is master here, or so he imagines. He’s expecting us, so we’ll just go on in.

Make sure the door is firmly closed behind you now; It tends to stick and Woody’s bench dog loves to jet out and root around in the neighbor’s garbage. No need to solve the mystery of why they call the fuzzy little leg-humper “Stinky.” (ツ)

Pine and cedar plane shavings litter the floor of Woody’s shop and their fragrant aroma fills the air erasing the mutt funk. Autumn sunlight filters gently through the single dusty window as sawdust motes dance above a limp bench cat sleeping at the far end of the workbench dreaming of buffalo wings and big-eyed kittens. All appears well in Woody World.

Woody’s sitting at his workbench on his white Smith & Wesson padded stool where he has just unpacked his new chisel, admired it, checked the fit, finish and edge, and appears quite satisfied. He lays out a test mortise hole on a piece of scrap oak, picks up his gennou hammer (the one with the classic Kosaburo head and the sexy Osage Orange handle that turned out so well), and begins to chop a test mortise. But, wait!… Something’s not right!

With trembling hands, Woody examines the chisel’s cutting edge to discover the last thousandth of an inch or so has changed from smooth and sharp to ragged and dull. “Nooooo!” Woody wails as he lifts his arms to the ceiling, arches his back, and slumps to the floor on his knees in a pose reminiscent of Sergent Elias in that poignant moment on the battlefield; “I have been betrayed!” he screams with wavering voice. Yes, Woody’s a talented and enthusiastic drama queen in the Smeagle mold; Maybe even good enough to run for the US Congress.

Another of Woody’s qualifications for high public office is that he dearly loves to pull a cork, so while he walks to the corner Piggly Wiggly to get a 5th of tequila to anesthetize his emotional shock and refill his thespian fuel tanks, let’s take a load off and sit on his workshop sofa over there while I explain the cause of his emotional fragility. Yep, you’re right; It’s a recycled bench seat from an old Power Wagon he salvaged from a junkyard and converted to a sofa for watching ballgames and taking naps in the shop away from the jaundiced eye of “She Who Must Be Obeyed.” Don’t worry about your pretty pink dress, princess, it’s just honest sawdust.

With tools, tequila, and the mystery of steel involved, this could be a long story, so let’s consider how to solve this particular mystery before Woody gets back and starts up his caterwauling again.

But just so you don’t become discouraged, let me state right now that there is a tunnel at the end of the light, and that while all seems dark and hopeless to Woody now, he may actually have reason to rejoice greatly! But we’ll get back to that later in the story.

The Questions

A Japanese blacksmith fluxing and placing a piece of high-carbon steel onto a hot piece of jigane in preparation for forge-welding the lamination of a blade.

Your humble servant always asks the following questions when someone complains of a chipped cutting edge on a chisel or plane. When Woody gets back, and if he manages to remain coherent and vertical long enough, we’ll ask him these same questions. If your blades are causing you grief, you should consider asking yourself these questions too. Jose Cuervo and acting skills are not required.

  1. What sort of quality is your problem chisel? Low? Medium? High? How do you know? This is relevant because a poor-quality chisel will fail just by looking at it too hard;
  2. What type of chisel is it? A striking chisel or a paring chisel? Each type of chisel is used for different tasks and in different ways;
  3. What and how were you cutting when the edge failed? This is important because some woods are best cut in a different manner than others, and some cuts require a special approach if we are to avoid damaging the chisel;
  4. What is the bevel angle? If the angle is much less than the ideal for the type of chisel, plane, cut and wood, we may have found the culprit. Finding the perfect angle for your chisel and situation may take some experimentation;
  5. How did the edge fail? Did it crumble? Chip? Roll? A combo failure (with cheese)? This will tell us a lot about the tool.
  6. Was the wood you were cutting dirty? Did it contain embedded grit? This is an important question because many people carelessly use their valuable chisels, planes and powertools to cut hard minerals instead of scrumptious wood. The lesson? Don’t be a slob: Scrub your wood with a steel brush before cutting it. And saw off the last 3~4 millimeters of every board, or at least chamfer the ends with a block plane, drawknife or knife to remove the grit always embedded in end grain, before you put it through your jointer, thickness planner or tablesaw, or cut it with handsaws, planes or chisel. If you have not made a habit of doing this, don your scratchy sackcloth tidy whities, smear ashes on your face, then repent and be baptized because you have been abusing your innocent tools, Bubba. Clean your wood and you will notice the difference. Strange that no one I have ever asked this question to has admitted to using dirty, stony wood at first. The reason is usually simply that they didn’t realize it was filthy until I pointed it out to them, just as it was pointed out to me many years ago. What’s that you say? You don’t have a stiff steel wire brush in your toolbox?! Shame on you;
  7. Did you abuse the chisel by trying to lever wood out of the cut, a mortise for instance? This is a common cause of failure. People accustomed to using amateur-grade tools with soft cutting edges frequently discover the edge of their new chisel chipped after using it like a cheap Chinese screwdriver to lever waste, never imagining the harder and more brittle steel of a quality chisel might be damaged. Such boorish behavior voids the warranty on our chisels, BTW, because a chisel is a cutting tool, not a prybar or a can opener, much less a screwdriver.

Did your answers to these questions suggest any remedial action to you? The best answer to Question 1 is often to procure a better-performing tool.

But if your tool is professional-grade instead of hardware-store grade, then you need to learn how to use it and maintain it properly. But that is a story for another day.

Let us shift our attention briefly to another, related mystery, one that has more to do with human nature.

Why Are the Blades of So Many Modern Tools Mediocre Performers?

It wasn’t always that way, but there are sound business reasons why chisel and plane blades are such poor performers nowadays, even in Japan, and like many things, it boils down to money. The numbers of craftsmen that routinely use handtools has decreased, and therefore the demand for professional-grade tools is way down. In Western countries the degradation of tool standards started even earlier.

In this situation, mediocre tools are simply more profitable. After all, low-quality materials are cheaper and it only takes ordinary machines and minimum-wage factory workers, not expensive trained blacksmiths, to make tool-shaped objects from mediocre-quality materials. Professional woodworkers won’t touch such crap, but amateurs, the inexperienced and those deluded, wandering souls who judge performance based solely on lowest cost buy them by the ton. More now than ever, sustainability is given pious-sounding pompous lip-service, while the reality of modern society is that high-volume sales of colorful but poor-quality tools designed to meet planned obsolescence goals, manufactured in lots of thousands by Chinese farmers, and destined to become early landfill stuffing has become the only viable business model left standing. Gofigga.

More importantly, even if they would do better if given half a chance, inexperienced amateurs seldom have anyone to teach them how to use and maintain their tools, so they never learn proper maintenance principles and cutting techniques. When they damage their woodworking tool blades carelessly, they blame the tool supplier for their own failure. As Mr. T would say: “I pity the fool.”

Faced with this sort of consumer, it is simply easier and more profitable for tool companies to manufacture, and for retailers to sell, chisels and planes with softer, tougher blades suited to amateurs. I think you can see the vicious cycle.

A kakuuchi oiirenomi chisel by Hidari no Ichihiro
An Atsunomi chisel by Hidari no Ichihiro

A Non-technical Technical Explanation

Your humble servant’s earlier comment that Woody may have cause to rejoice about what appears to be metallurgical malfeasance may cause some Gentle Readers to wonder if I am mad as a sack of owls; Perhaps my most excellent aluminum-foil skull cap (the one with purty curly copper wires) malfunctioned permitting those icky inter-dimensional aliens’ mind-control waves to leak through.

Like our absent drama queen, I too was devastated when first faced with the Mystery of the Brittle Blade, but I can explain why it may be sign of a blessing instead of a curse. It’s elementary dear Watson. But I think it best to provide some background and explain some time proven solutions before presenting the good news. Steak before ice-cream, you see.

I beg the indulgence of knowledgeable Gentle Readers who feel insulted by the lack of temperature curve drawings and jargon such as “pearlite,” “martensite” and “ austentite,” and ask them to understand that, while this blog is focused primarily on informing our professional Beloved Customers, many Gentle Readers require a less technical explanation. Simple hospitality demands that your humble servant make an effort to provide useful insight to a wide range of Gentle Readers. As a dude wearing a skirt and sandals in a movie once said: “ Are you not entertained?”

A shinogi oiirenomi chisel blade by Hidari no Ichihiro

Quenching the Blade

When a blacksmith quenches a high-carbon steel blade in water in the ancient manner (called “Yakiire” 焼き入れ in Japanese which translates to “burn in” in English), the steel suffers a thermal shock, sometimes severe enough to crack it. This violent cooling also causes a peculiar crystalline structure to form in the metal, one that causes it to become harder and increase in volume, and to warp to some degree. The casual observer may imagine the water cools the entire blade uniformly, but ‘tain’t so.

Those areas of the blade that cool the quickest form the highest volume of crystals and become hardest. In the case of chisels, planes, and kiridashi knives, the end of the blade has the most exposure to water, cools quickest, and therefore becomes hardest, at least during the first quench.

The blacksmith may carefully repeat the heating and quenching process multiple times, sometimes varying the heat time and temperature to achieve the desired crystalline structure and uniform distribution of small, hard carbides that define “fine-grained steel,” but the quenching process by itself always leaves the blade too hard and too brittle to be useful as-is.

Tempering the Blade

Now that the blade is hardened, indeed too hard, the blacksmith must mellow the steel, reducing its hardness while at the same time increasing its toughness by carefully reheating and cooling the steel to modify the crystallized steel in a process called “tempering,” in English and “yakimodoshi “ 焼戻し ( literally “ burn return” ) in Japanese. In this way, a steel blade hardened to Rc85 degrees during the first quench, indeed brittle enough to break into pieces if dropped onto a concrete floor, can be softened to a useful hardness while becoming at the same time much tougher.

In materials science and metallurgy, toughness is defined as the ability of a material to absorb energy and elasticly deform without fracturing. To “elasticly deform” means an object changes shape or deforms when pressure is applied, but returns to its original shape when the pressure is removed. For instance, if you clamp one end of a piece of mild-steel wire in a vise and apply a little force with your hand at the other end it will bend at first and then spring back to its original shape when you remove pressure. This is called “elastic deformation.” But if you apply enough pressure the wire will not spring back (“rebound”) but will remain bent. This permanent bend is called “plastic deformation.” Mild steel wire is truly “tough as nails.”

Glass is the opposite case. While it may exhibit more elastic deformation than most people realize it can, it will tolerate no plastic deformation, because when the stresses in glass reach the “yield point,” instead of bending plasticly, it breaks.

A brittle blade is hard but not tough, and while it will elastically deform a little bit (often so little it’s unnoticeable), it too easily breaks. Proper tempering therefore, is critical.

But this reduction in hardness and increase in toughness brought about through tempering is not always 100% uniform, and as mentioned above, the extreme cutting edge of the blade of a chisel or plane tends to be hardest and therefore most brittle in the case of hand-forged tools, even after tempering. The cheap, mass-production solution is to simply make the entire blade softer, say Rc55 for example, so brittleness will never be a problem. But such a tool is more a sharpened screwdriver than a cutting tool suited to the needs of professional woodworkers, IMHO.

I’m being too harsh, you say? Not even a little bit. A soft blade dulls quickly, wastes the professional woodworker’s time and money, and is irritating instead of useful. Perfect for turning screws, spreading spackle or stirring paint but not much good for quickly and precisely cutting lots of wood for pay, thank you very much.

Solutions 1 & 2

The Mystery we are investigating on Woody’s behalf is as ancient as steel itself. And of course there are reliable ancient solutions our blacksmiths employ. Let’s consider two of them.

First, create a crystalline structure in the blade through hand-forging that is more resistant to fracturing than ordinary steel regardless of its hardness. This doesn’t happen by accident.

Second, employ painstaking heat-treatment techniques combined with uncompromising quality control to achieve the right balance of hardness vs. toughness.

To help control the heat-treat process, our blacksmiths apply a special mud-like compound to specific areas of the blade to slow down the thermal shock during the quench and improve the steel’s crystalline structure. Every blacksmith has their own “secret sauce,” so I can’t tell you what it’s made from. This technique is not perfect nor unique to Japan, but we know it has been successfully used by Japanese swordsmiths for at least 900+ years

It ain’t rocket surgery, but factory workers in Guangzhou or Mumbai can’t do it.

So, we have discussed the reasons, and some solutions, but what to do about a blade that’s already chippy?

Solution 3

Assuming the blade has been forged by an expert blacksmith in accordance with the principles outlined above, the fix to chippiness (oops, did I coin a word?) is to be patient and sharpen the blade three or four times removing the extra-brittle steel exposed at the cutting edge, the area that became harder and less tough than the rest of the blade during the heat-treating process. With few exceptions, the blade will then “calm down” and stop misbehaving.

This is the solution we ask our Beloved Customers to employ when this problem infrequently arises. It requires faith, and patience, but it almost always works.

Solution 4

The last solution, and one I certainly do not recommend to anyone except as a last resort, is to heat the cutting edge under a candle flame. Not an acetylene torch; Not a propane torch; Not even a butane lighter; A candle flame only. You want the extreme cutting edge to become just a smidge hotter than you can comfortably touch with your bare finger. Don’t heat the entire blade, just the cutting edge.

BIG FRIKIN DISCLAIMER 1: This method won’t fix a poor-quality blade or one that was initially ruined during forging or heat-treat.

BIG FRIKIN DISCLAIMER 2: If you are careless and do this wrong you can easily ruin the blade!

Rejoice Greatly!

But what insanity made me say that Woody should rejoice when the cutting edge of his new chisel crumbles? I assure you, my reasoning is sound, I have Woody’s best interests at heart, and I will explain all to him when he sobers up. Probably tomorrow afternoon, at this rate. (ツ)

But I’ll explain it to you now, if you will be good enough to get me a root beer from Woody’s cooler over there to wet my whistle. No, that’s not a Class M-3 Model B-9 General Utility Non-Theorizing Environmental Control Robot, it’s one of those mini-fridges sitting on two skateboards with a shop-vac wrapped in Christmas lights perched on top that Woody puts out on his front porch for Halloween to thrill the kids and to keep a sufficient stash of cold adult beverages, and root beer too, of course, close at hand. He’s very practical that way. Oh, BTW, please don’t tell SWMBO about the adult beverages, or you’ll ruin a great Halloween tradition and preclude many erudite discussions in the future: Vino Veritas

Ahh, that’s better. Nothing like an ice-cold root beer.

Now where was I? Oh yes, the reason for my optimism: A high-quality blade that crumbles like Woody’s did when brand new, and mellows after a few sharpenings, is highly likely to be an exceptionally fine tool!

On the other hand, a blade that is too soft when new will never crumble or chip, but it will always quickly dull and never improve. A veritable gasket scraper. (个_个)

There are exceptions, of course: some hand-forged blades are defective and crumbly from beginning to end, usually a result of overheating the steel during the forging process, a rookie mistake. You should return such a defective blade to the retailer you purchased it from. If, however, to save a few bucks, you bought a tool without a warranty, or purchased it from an online auction, you will need to enlist the services of Murphy’s two bubbly buddies Mr. Doodly and Mr. Squat.

Somehow I doubt Woody will thank me for solving this piece of the Mystery of Steel for him, but I am confident he will love the flavor of that chisel for the rest of his life.

YMHOS

PS: If you found this interesting, you may find other posts regarding the Mystery of Steel found in our “Sharpening Series” interesting too. The one at this link in particular is relevant to this discussion.

A kakuuchi oiirenomi chisel by Hidari no Ichihiro

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 I gag on a hairball if I lie.

Relevant Posts:

The Story of a Few Steels

Professional-grade Tools

The Care and Feeding of the Wild Mortise Chisel – Part 1

Sukezane brand 9mm mortise chisel (mukomachinomi) side view

It is well with me only when I have a chisel in my hand

Michelangelo 1475-1564

This is the first in a five-part series about the Mortise Chisel, especially the Japanese version.

Also called the “Joiner’s Chisel” in Japan, this is a specialized chisel used by specialist craftsmen to cut precise, smallish joints when making furniture, cabinetry and joinery. Carpenters don’t use it, and few have even seen one.

In this post we will briefly examine a tiny bit of the terribly long history of the mortise and tenon joint, and give a description of this specialized chisel.

In future posts we will look at how to evaluate, adjust and even how to use the Japanese Mortise Chisel. We will also touch on bevel angles and blade hardness problems.

We will discuss what to look for in a good mortise chisel and how to examine it with an eye to increasing its performance. This is something most users of chisels never consider, but it can make a big difference in the case of mortise chisels. Indeed, I daresay most Gentle Readers will mutter the equivalent of “Splish us and splash us” when they read it.

Of course we will also discuss how to effectively correct irregularities in our mortise chisel that negatively impact performance, irregularities most people never notice.

After it is fixed (they almost always have some problems) we will take our racing chisel out for a few laps, but prior to that we will consider how to effectively use this specialized tool. Too few receive proper training nowadays in chisel work, but here are C&S Tools we feel it our duty to help our Beloved Customers improve their skills.

We will conclude this series by taking the “Old Master’s Test,” just to make sure both our mortise chisel and our skills are improving.

While focused on the Japanese mortise chisel, the principles and improvements discussed are applicable to any chisel used to cut mortises.

While all Gentle Readers with eyes to see, ears to hear, and hands that love wood are welcome to share this hard-earned knowledge, it is intended primarily for our Beloved Customers, especially those who use chisels professionally to keep body and soul in close proximity.

Some Background

Your humble servant drafted this series of posts years ago, and has shared bits of it with Beloved Customers from time to time when requested, but the information has not always been well-received for a number of reasons.

There is an old Japanese saying, one which probably originated in China, written 「馬の耳に念仏」and pronounced “Uma no mimi ni nenbutsu,” which translates to “Prayers in a horse’s ear.” Why are Buddhist prayers relevant you ask? Good question. You see, some of the principles I will present in this series directly contradict doctrine taught by some of the woodworking Gurus in the West. Like vespers to a beast of burden, wisdom is wasted on the willfully, woefully ignorant (wow, that almost sounds like iambic pentameter!).

But our Beloved Customers are neither horses nor asses nor politicians but shockingly intelligent human beings to whom your humble servant is convinced the time has come to expound the gospel of the mortise chisel. Perhaps it will be canonized some day (ツ)

This series of posts is equivalent to a graduate school course in chisels, something like “Mortise Chisels 701.” And just like a course in advanced differential equations, most Gentle Readers will never need it. But never let it be said that your humble servant didn’t do his best to improve both the skills and the tools of our Beloved Customers.

Some History of the Mortise & Tenon Joint

Mortise chisels are used for cutting rectangular holes in wood usually intended to accept tenons to form a structural connection called the “mortise and tenon joint” between pieces of wood.

No one knows how long humans have been using the mortise and tenon joint, but it has certainly been longer than nails, and many thousands of years longer than screws, although modern humans with their lithium battery-powered, made in China, landfill-bound, multicolored plastic and rubber screwdrivers may find it difficult to imagine. So let’s begin the journey by examining just two well-documented extant physical examples that may provide motivation for using this enduring joint.

The oldest known wooden structure is a neolithic well liner discovered near Leipzig Germany, constructed from oak timbers shaped by stone adze and joined at the corners with half-lap joints and pinned tusk-tenons at through mortises. Tests indicate the trees the timbers were split from were felled between the years 5206 and 5098 BC, making the assembly at least 7200 years old.

Next, let’s look at a less soggy but more recent, complicated and elegant example.

The oldest existing wooden building in the world is a Buddhist Temple named Horyuji located in Nara Japan. Originally constructed around 600 A.D. and rebuilt around 700 A.D. after a fire, this huge 1300 year-old temple and pagoda complex was reconstructed using hundreds of thousands of mortise and tenon joints, testifying to the longevity of wooden structural systems and the value of this universal connection technique.

Horyuji  is far more than just a temple to Buddhism, it is a temple to woodworking. If you haven’t yet visited it, you’re truly missing something. 

I mention these two examples to illustrate the universality, strength, and durability of the mortise and tenon joint. Anyone serious about woodworking must master this most ancient and essential connection.

The mortise chisel is the best handtool for the job of cutting mortises less than 15mm in width. For wider mortises, oiirenomi or atsunomi are more efficient.

Japanese Mortise Chisels

12mm mortise chisel (mukomachinomi) Face View
12mm mortise chisel (mukomachinomi) Side View
12mm mortise chisel (mukomachinomi). Please notice the rectangular cross-section precise right angles, and straight, clean sides. This is the most precise of the Japanese chisels.

In the Japanese language mortise chisels are called “mukomachi nomi” (向待鑿), with “nomi” meaning “chisel.” Don’t ask me the origin of the rest of the word because I don’t have a clue, and have heard few plausible explanations. There is another post linked to here that contains more information about this chisel.

I will use the term mortise chisel in this article to refer to mukomachi nomi.

For our Gentle Readers interested in the Japanese language, there are several combinations of Chinese characters used to write mukomachi, none of which make much sense or seem related in any way to either tools or woodworking. The most common characters used are “向待” with the first character meaning “there” or “direction,” and the second character meaning “wait.” Combined, they seem to mean “Waiting over there,” or something like that.

I assume the name was originally phonetic and somebody decided to use these kanji because their pronunciation matched the phonetic name. This sort of linguistic contortion is seen frequently in Japan, and has been a source of confusion for all and sundry for many centuries. I blame it on elitist Buddhist priests going back and forth between Japan and China over the centuries, but it is typical of the Japanese people in general and priests in particular to take a perverse pleasure in intentionally making and using terms others can’t figure out.

This confusing practice is not unique to bald priests. When I was an engineering student, I recall the professors insisting we never attempt to simplify or too clearly explain the technical jargon of the trade to non-professionals because it was essential to job security for them to never quite understand it.

If you are familiar with Japanese architecture, you have seen the wooden lattice work that defines it in doors, windows, dividers, shoji, fusuma, koshido, glass doors, ceilings, and even fences, all items made by “tategushi” or “joiners” in Japan. Each piece of any lattice needs two tenons and two matching mortises to stay in-place, so a single piece of traditional Japanese joinery may have literally hundreds of small, very precise mortises, indeed thousands in the more complicated pieces. The Japanese mortise chisel was developed specifically at the request of joiners for this type of work. Therefore, it is also known as the “Tategu Nomi” which translates to “joinery chisel.” Few carpenters use this chisel.

Nora Brand 6mm Mortise Chisel (Mukomachinomi) Side View
Nora Brand 6mm Mortise Chisel (Mukomachinomi) Ura View
Nora Brand 6mm Mortise Chisel (Mukomachinomi) Shoulder View. Exceptional shaping and filework .

Japanese mortise chisels are similar to other Japanese chisels in having a laminated steel structure with a hollow-ground ura (flat), an integral tang, wooden handle, and steel ferrule and hoop. Unlike most other chisels it has a rectangular cross-section with sides usually oriented 90˚square to the hollow-ground ura, and either flat or just slightly hollow-ground to better keep the blade aligned in the cut and to dimension and smooth the mortise’s walls.

Western mortise chisels do not typically share this detail, although unusually intelligent and observant Western woodworkers of course modify their chisels to gain similar benefits.

If speed and precision are important to you, then the sides of the chisel being oriented at 90° to the ura absolutely provide a serious advantage when cutting most mortises because the sides, and especially the two sharpish corners where these three planes meet, will effectively shave and precisely dimension the mortise’s side walls as the mortise is being cut without the need to pare them later.

Unlike most mortise joints cut with oiirenomi or atsunomi, so long as the mortise is the same width as the mortise chisel, and the user has the ability to maintain the chisel at the right angle while striking it with a hammer, the width of mortises cut with this chisel are usually quite precise and seldom if ever need be cleaned with a paring chisel. This functionality means that you can cut mortises, and especially small ones, both precisely and quickly with great confidence. It’s not called the “joiner’s chisel” for nothing.

The mukomachi chisel does not work as well in wider widths because of the increased friction between the chisel’s sides and the mortise’s walls. For joints wider than 15mm, please use a trued oiirenomi or atsunomi. And don’t forget to use your oilpot.

In the next class in our graduate course on the care and feeding of the wild mortise chisel, we will examine the various details to look for in an effective mukomachi nomi. Most of these details are applicable in the case of other chisels such as oiirenomi and atsunomi too, indeed any chisel intended to be used to cut mortises including Western mortise chisels.

But wait a minute! Before ya’ll run out of the classroom like a caravan of crazy stoats chasing a pixie, please pick up your homework assignments from the table by the exit doors. And please, don’t leave your empties behind on the floor. Paper coffee cups are one thing, but aluminum beer cans attract out-of-work divorce lawyers and other such desperate vermin.

See you next time.

YMHOS

Your most humble and obedient servant’s set of well-used mortise chisels. The 8 pieces on the right are by Kiyotada (1.5mm~15mm). The two 2 newer chisels on the far left are by Nora. Over the years I have used these tools both professionally and as a hobbyist more than any other of my chisels, as you can perhaps tell from the differing blade and handle lengths which have become shorter with use. A stoic tool, they gossip among themselves less than most other chisels. Good friends and reliable workmates that helped pay the rent and feed the wife and babies for many years.

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.

YMHOS

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 and our ancient blacksmiths that actually make and work 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 technical 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 pull the other one.

There are those who insist they can tell the difference between steels by licking them. Your humble servant has never tested these claims, even on a dare, and never will, so please don’t ask.

Since your humble servant can read and write Japanese, I feel foolish calling it 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 just over there. A change into period-correct wardrobe will not be necessary, but please put away your iPhone and try to not embarrass yourself in front of the locals.

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, 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 a 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 this rock we call home, 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.

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.
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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.

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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.
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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 foreign 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 advance 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 sneak in 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 produce steels 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 but too much decreases impact resistance), and Sulfur (a demonic chemical that reduces strength, increases brittleness and 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 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 no matter 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, axes, sicklesHighest-quality cutlery,  planes, knivesHigh-quality cutlery, planes, knives. 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 sawblades forged from White Label No.1 tend to be fragile unless the blacksmith removes excess carbon during forging to improve toughness.

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 or Blue Label No.2 are 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 tougher, 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.

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 gird up their loins and ready 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 tempermental White Label steel. The reasons are made clear in the Technical Example below.

Quenching & Tempering

The process of hardening steel, called “heat treatment,” is key to making useful tools. Modern 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 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 more 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. 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.

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.

An interesting example is a sword blade. 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.

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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.
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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 “wear resistance” to mean “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 honesty 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 easier, quicker and more pleasant to sharpen. That sums it up. To some people this difference matters 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.

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 it started out a little sharper, it will cut 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 if 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 a real-world 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 carbon combine to form a hard crystalline structure, desirable 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 Ferrite and spherical carbon 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 ferrite and spherical carbon are mixing, forming some gray-colored Martensite, but there are still big lakes of Ferrite visible. This is not acceptable.

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 Ferrite and spherical carbon 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 Ferrite or islands of 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 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. in Figure 9, there are many white tissues observed 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.

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, and laments the inevitable corrosion. Being bald as a bowling ball, I’m desperately jealous of her long hair, but it must get in the way when working the stones.

The Essential Oilpot

The Matsui Precision Notched Straightedge

Matsui Precision Bevel-edged Straightedge with notch

You cannot teach a crab to walk straight.

Aristophanes

This post is about a tool that looks quite ordinary but is in fact extraordinary in subtle ways.

Why Do Woodworkers Need a Good Straightedge?

When woodworking we need to be able to mark and measure straight lines and examine the precision of edges and surfaces. There are several ways and tools available to accomplish these tasks, but the steel straightedge is efficient for shorter distances, assuming one’s straightedge is up to the job.

For most woodworking tasks we don’t need a precision straightedge. But for those few activities where it is necessary, nothing can take its place. So what are some of those activities? I can suggest a few from my experience:

  1. I use a precision straightedge as a “Standard” to check that my working straightedges and squares (the ones that are used and abused daily) are truly straight and square. This is necessary because, during use, Murphy governs all operations, while pernicious Iron Pixies dance among the piles of dandruff on his shoulders. Due to their malicious ministrations, measuring and marking tools are easily damaged, wear-out, and lose tolerance so I need a reliable “Standard” to check them against regularly. Of course, you can’t check for straight or square unless you have a truly straight line/surface to index from. It would be silly to imagine that the edge of one’s tablesaw top or jointer table are perfectly straight without first checking it against a reliable standard;
  2. I use a precision straightedge to examine the soles of my handplanes to help me keep them straight, flat and free of wind because it’s very difficult to plane a flat surface with a screwy plane. No matter how much time I invest in truing my planes, I’ve found the results are never better than the straightedge used.
  3. Check that lapping plates and the float-glass plate I use for truing stones and plane soles remain within tolerances. Yes, they wear out too.
  4. Check that the tables of stationary equipment such as tablesaws, bandsaws, jointers, and planers are true, and that infeed/outfeed soles of handheld electrical planers are properly aligned;
  5. Check that surfaces of wooden components of special projects requiring extra precision are true.

Do you ever need to accomplish any of these tasks?

Tasks for Which the Matsui Precision Straightedge is Not Ideally Suited

The Matsui Precision Straightedge is not an expensive tool, but since it is one I rely on, it is most cost-effective to protect it from premature wear and damage, so the following are tasks for which I use a less-expensive and less-protected “working straightedge” instead of my Matsui precision straightedge:

  1. I don’t use it for checking sharpening stones. The Matsui straightedge can do this job with style, but after a few years of being pressed against (and dragged over) abrasive stones, the tool’s precision would be degraded. Better to use a less-expensive straightedge for this job, and check it occasionally against the Matsui Precision Straightedge to confirm it’s still straight. If it isn’t, fix or replace it.
  2. I don’t use it for daily general woodworking tasks. Once again, the Matsui straightedge can do general jobs with style, but after a few years of being pressed against (and dragged over) wooden surfaces, the tool’s precision would become degraded prematurely. Instead I use a “working straightedge” that has been checked against my “Standard” Matsui Precision straightedge;

How To Use a Precision Straightedge for Checking Tools and Surfaces

Neither the human hand nor eye can measure a straight line or a true plane with any precision unaided, but there is one technique older than the pyramids all woodworkers must be proficient at, namely to place a truly straight, simple straightedge on-edge on a surface to be checked, be it a board, a jointer outfeed table, or the sole of a plane, and shine a light source at the gap between the straightedge and the surface being examined. If gaps exist, light will pass between the edge of the straightedge and the surface being checked confirming the surface is not straight and/or flat. The human eye can detect even a small amount of light this way and both quickly and effectively judge how flat the surface being checked is with a surprising degree of accuracy.

Feeler Gauge

Another technique that yields more precise values without relying on Mark1 Eyeball is to place the straightedge’s beveled edge against the surface to be checked, and insert feeler gauges into gaps between the straightedge and the surface. If the feeler gauge selected won’t fit, then one replaces it with thinner gauges until one that just fits is found.

Once you know the value of the gap between your straightedge and the area of the board you need to true, for instance, you can divide the measured thickness of the shaving your planes takes in a single pass (easily checked with a vernier caliper) to calculate how many passes it will take to true the high-spots on a board. eliminating a lot of the guesswork that makes precise woodworking difficult at times.

To reliably perform these checks, we need a truly straight straightedge. Straight is a relative thing, but straightedges sold for woodworking are seldom straight because purveyors rely on purchasers to not bother, or even know how, to check the quality and precision of the straightedges they sell.

Another reason honest, precision straightedges are relatively rare among woodworking tools is that making a high-tolerance piece of hardened steel that is straight, and will stay that way, is hard work that most woodworkers are neither inclined to appreciate nor bother to check, much less pay for. Is ignorance bliss? I believe it is in the natures of our Gentle Readers to always strive to improve the quality and efficiency of their work. A high-quality precision straightedge is an essential tool in that blissful quest.

Challenges & Solutions

The dilemma of the straightedge is that it must be thick and rigid enough to prevent warping and flopping around in-use, but reasonably lightweight and not too bulky or it will be clumsy. At the same time, it must not be too thick, or it will block out most of the light passing between its edge and work-piece making it useless.

Another challenge the straightedge faces is the constant threat of damage. If the delicate edge is too soft, it will become dinged and deformed instantly becoming inaccurate. And if the straightedge rusts (the bane of steel since ancient times), precision will suffer.

What are the viable solutions? They are obvious and proven, but seldom implemented well. Here is how Matsui Precision does it.

Stainless Steel Construction

First, they use high-quality stainless steel to prevent corrosion. If you work in humid conditions or if you will admit to perspiring salt-laden moisture at times, then this is important, but not rare.

Properly-sized, Precision-ground & Polished

This straightedge is not an insignificant piece of stainless steel. It is available in various lengths, but in the case of the Matsui’s 400mm straightedge (a handy, reasonably-priced length), the blade is 34mm wide and 3mm thick, enough to keep the blade rigid in use and prevent warping, but not so wide or thick as to feel heavy or clumsy. It weighs 320gm, a nice balance of rigidity and weight.

Compact, lightweight tools made using quality materials efficiently have a deep genetic attraction to the Japanese people.

What is more rare is the fact that Matsui then precision-grinds and precision polishes the stainless steel (not the same thing) so the tool is as straight and flat as machinists require, because this is a tool designed to the higher standards of machinists, not just woodworkers.

Hardened & Trued

Matsui also hardens the stainless steel to ensure the tool is rigid and will resist wear and damage over its long useful lifespan.

During heat treating and grinding the metal warps slightly. After stress-relieving the tool, Matsui inspects each tool one-by-one and corrects irregularities or rejects those that cannot be sufficiently corrected. It’s called quality control, something that never happens in China or India in the case of tools intended for woodworkers.

Beveled Edge

To make it easy to see light passing between the straightedge and surface being checked, one edge is beveled. The importance of this detail cannot be overstated.

The Notch

The Matsui Precision Straightedge being used to check the sole of a 70mm finish handplane with a blade by Sekikawa-san. The notch fits over the cutting edge so one can check the sole with the blade protruding as it will be in-use. In this photo the blade has been extended waaay too far out of the mouth to make it easy to see the cutting edge. Please notice the light showing between the straightedge and the sole indicating that something is not right. The wedging pressure of forcing the blade to project this ridiculous amount has warped the block so that the most important part of the sole, the area directly in front of the mouth, is not touching. The point is that the notch makes it possible to check the sole with the blade projecting the intended distance, a job simply not possible with an ordinary straightedge.

In the case of the tool we are introducing here, Matsui cuts a small semi-circular notch in the beveled edge of the blade to provide clearance for irregularities in the surface being checked, such as welds, or in the case of woodworking tools the cutting edges of the blades of handplanes, electrical planers and electrical jointers. This is an important and unique feature.

Why is this notch so useful? The problem with using a metal straightedge to check/true the sole of a handplane has always been that, in order to correctly check for flatness/wind, the blade must be set to project from the plane’s mouth the same amount it should be when the plane is being used, because in the case of Japanese planes the wedge-shaped blade applies slightly different pressures on the wooden block at different depths in the block, producing variable degrees of deflection.

But if the blade is projecting from the mouth from the same amount as it will be in use, then the straightedge will ride on top of the blade preventing a proper examination, and at the same time, possibly dulling the blade and gouging the straightedge. The solution has always been to adjust the blade to not actually project, but to be just in-line with the sole, a fiddly process that has resulted in many dulled blades, scratched straightedges, and inaccurate examinations.

With the elegant Matsui Precision straightedge, however, the notch fits directly over the projecting blade avoiding the irritating and time-wasting fiddling normally required to get the blade in the exact position, one that ultimately yields an imperfect reading.

If you need to maintain handplanes, electrical woodworking tools, or do precision woodworking and need an accurate, reliable, lightweight, durable, reasonably-priced straightedge to help take the guesswork out of these jobs, this product is just what you need. I have been using one for years and couldn’t get by without it.

If you are interested, send us a message using the form below.

YMHOS

Kireaji 切れ味

‘Be careful you don’t cut yourself. The edges are sharp enough to shave with.’
‘Girls don’t shave’, Arya said.
‘Maybe they should. Have you ever seen the septa’s legs?”

George R.R. Martin, A Game of Thrones

I mentioned in a previous article my belief that a love of sharp tools is embedded in the Japanese people’s DNA. I am convinced this is by no means limited to the people of these mountainous green islands. I know it is deep in mine too, and it may be in yours.

Whether they were made of bone, flint, copper, bronze or iron, humans of all races and all locations worked with axe and adze, chisel and scythe, sword and dagger to keep body and soul in close proximity for many thousands of years before written language was invented or Microsoft products crashed. Our reliance on and love of sharp tools is still part of our DNA, to one degree or another, and for good reasons.

The words we humans make and use give insight into our deeper natures, so a very brief lesson regarding a single word in the Japanese language, one that is an intentional, defining characteristic of our tools, and one you will not find in any textbooks, may be illustrative of this point.

Cutting Flavor

The word your most humble and obedient servant has in mind is “kireaji” 切れ味 pronounced “ki/reh/ah/jee. This word is comprised of two Chinese characters. The first of the two ideograms being 切 , which is pronounced in its un-conjugated form as “setsu” or “kiru,” meaning “cut.” This is an interesting character. People who study these things say it is an ancient combination of two characters. The small one on the left looks like the character for the number seven 七, but actually it represents a vertical and crosswise cut in the shape of a plus sign 十. The character to the right, 刀 , is pronounced “to” or “katana” and means “sword.” So “kiru” means to cut with a sword or blade.

The second character in the word is “Aji,” 味 meaning “flavor.” Combined, these two characters mean “cutting flavor,” but the resulting word has nothing to do with the human sense of taste and everything to do with the feeling transmitted to the user when a blade is cutting. This word is used in reference to all cutting tools from axes to swords to razors, and certainly for knives, chisels, and planes.

In the English language, the closest word we have is “feeling of sharpness,” I suppose, but it isn’t the same. The act of cutting, in the Japanese tradition, is a sensory experience, one that can be pleasant, in the case of a well-designed sharp blade, or unpleasant in the case of a clumsy dull blade. I think you now have a sense of what the word kireaji means, and how how it feels. Do you understand why it is an important word when talking about tools?

When we speak with our blacksmiths and sharpeners about the tools they produce, the kireaji we expect of their products is always part of the discussion. A blade can have a good kireaji (良い切れ味, an indifferent kireaji (どうでもいい切れ味)or a “distasteful” kireaji (不味い切れ味). It can be “brittle” (切れ味が脆い)or it can even be “sweet” (切れ味が甘い)meaning soft as a spoiled child. We always insist the first meaning be applicable because anything less is failure. Even if some of our customer’s tastes may not be refined enough to discern the difference, ours are.

We work closely with our blacksmiths and sharpeners to make sure they understand our requirements for sharpness. And just to be sure, we constantly test their blades to ensure compliance. If you buy a tool from us that has an especially sharp edge and looks like it may have been used lightly, please understand this is part of our QC efforts and not a return or a reworked reject.

If you know of other languages that have a similar idiom, please let us know in the comments section below.

Like the flavor of fine wine, rich chocolate or gourmet donuts (mmm donuts), the kireaji of cutting tools varies with materials, blacksmiths, and specifications. At C&S Tools we are not satisfied with outward appearance only, but take our products to a different level by making kireaji the very highest priority. This makes C&S Tools almost unique among retailers of edged tools.

Does kireaji matter to you?

Bon appetite!

YMHOS

If you have questions or would like to learn more about our tools, please use the questions form located immediately below. Please share your insights and comments with all our readers in the form located further below labeled “Leave a Reply.” We aren’t evil Google or incompetent facebook and so won’t sell, share, or profitably “misplace” your information.

Safety Rules & Habits for Edged Handtools

The chisels, knives, and planes we sell are all hand-forged by ancient smiths. There may or may not be dwarvish ancestry in one or two cases, but without exception our blacksmiths make blades with unsurpassed crystalline structure that cut like Satan’s scalping knife.

The Psychology of Steel

It’s important for those of use who use such sharp handtools to understand how they think. Allow me to put on my metallurgical psychologist’s hat for just a moment to expound. FYI this hat is a highly-polished brass skullcap engraved with runes of power and decorated with multiple rings of tiny silver bells suspended from stubby brass rods attached to the cap that tinkle prettily when I walk. Much glitzier but more dignified than the aluminum foil cap with projecting curly copper wires I use to protect my mind from the brain-rays of alien used-car salesmen. But I digress.

High-quality blades are especially single-minded and simply live to cut wood. If you don’t believe me, just ask them. You will hear the chirping and tapping sounds they make when they are happy, if you listen carefully. And the shavings and chips that fly from their milky silver edges will attest to the fun they are having. They love cutting wood best of all, but the problem is they will try their darndest to cut anything they can latch onto. It’s just their nature; something we must understand if we are to prevent the servant from becoming the bloody master in the blink of the eye.

First Real Injury © 2007 Sauer & Steiner

Safety Rules vs. Safely Habits

Everywhere we look nowadays there are rules and busybodies busily enforcing them. They don’t call it the “nanny state” for nuttin. Safety rules can be helpful but don’t do us any real good unless we we eventually turn them into those unconscious actions commonly called habits. Like never pointing the barrel of a rifle at anyone anytime even by accident, or putting on the car’s brakes before the vehicle crashes through the storefront, the potential consequences are just too severe to leave them as empty rules.

I don’t want to sound like a nanny, but as someone who has made one, perhaps even two stupid mistakes in his lifetime (difficult to believe, I know), I would be derelict in my duty if I did not point out one rule and a few wise safety habits worth developing especially to those of our Beloved Customers that purchase our chisels and knives and want to continue to have more than just an emotional attachment to their fingers, hands, toes and feet.

The Big Safety Rule: Don’t Let Them Bite You

The most important cutting-tool safety rule you need to follow is: Don’t let them bite you!

Sharp wide blades can sever a lot of nerves and tendons in the blink of an eye. A deep injury won’t even be painful if your blades are sharp, at least at first, but the damage may be impossible to repair fully and too often is life-changing, and never in a good way. So the application of this rule is simply don’t give cutting tools an opportunity to do mischief.

Safety Habit Number One: Never Cut Towards Yourself or Anyone Else.

OK, now that the big safety rule is on the table, let’s break it down into three basic safety habits. First, never ever ever never cut towards yourself or anyone else.

An example. A universal mistake everyone, without exception, makes at least once is to hold down a piece of wood with the left hand while cutting it with a chisel or knife motivated by the right hand towards the hand holding down the wood (in the case of right-handed people). They slip, or the chisel or knife jumps out of the cut, or the chisel or knife is dull and they lose control, or they apply too much force, or don’t allow enough distance to slow the tool down after the cut should end. Whatever the cause, in the next instant the wood quickly changes a pretty crimson color, and the left hand feels strange. So please, never ever ever never allow your hands to get in this situation. Assume I’ve now yelled this warning into your ears 50 times and hit you with a wooden mallet with each cockroach-killing screech to make the lesson sink in. It’s that important.

Safety Habit Number Two: Reject All Distractions While You Have a Cutting Tool in Your Hand


Another common mistake everyone makes from time to time is to allow a distraction to control us while holding a chisel or knife. For instance, trying to juggle a can of beer and a chisel at the same time may place your nose or eyeball at risk (alcohol is such an uplifting beverage); Or scrambling to answer a cell phone call without setting the chisel down first may result in the sudden appearance of an inconveniently leaking red nick in your neck that doesn’t quite compliment the fashion statement being made by your hand-embroidered woodworking robes.

Case in point: Many moons ago before my beard turned white I was cutting mortises with a sharp chisel at my workbench, using the time-honored butt clamp, of course, when a yellow-jacket wasp (of which I have an uncontrollable phobia ever since a frantic encounter as a small child with a hornet’s nest in Grandma’s attic), landed on my leg. In a blind panic I swiped the wasp off my left thigh with my left hand, which by total coincidence was also holding the chisel. 40 years later I still have that big unsightly scar that ended my promising career as a bikini model before it really got started, robbing the world of great beauty (ツ)。


Professional woodcarvers all know somebody with deep, crippling injuries to nerves and tendons in hands or legs from using carving tools improperly or while distracted. Not a few have lost whole hands. The wise ones wear kevlar or steel mesh gloves when they must secure work by hand while using chisels or knives. While I don’t condone it, professional woodcarvers must sometimes violate the rules just to get the job done. These safety gloves are good for preventing slicing cuts, and help to reduce the severity of injuries in all cases, but may not stop a knife or chisel from stabbing you if it is motivated, so please don’t violate the first rule just because you’re wearing fancy gloves.

The solution? Set your knives and chisels aside in a safe manner and location before you do anything other than cutting wood. In other words, have the self control and situational awareness to reject all distractions.

Oh yea, and please don’t drink and drive chisels.

Safety Habit Number Three: Always Set Your Tools Aside in a Safe Place and So They Can’t Move

This final safety habit is related to number two above in that distractions often cause us to violate it. In this case the hazard is a chisel or knife falling from a work surface, at which point Murphy rolls up his sleeves, licks his eyeball with his long purple tongue, and painstakingly guides the tool cutting-edge first towards ankles, feet and toes. In Japan were work has traditionally been performed while sitting on the floor, a common problem is accidentally kicking a chisel. Of course, the chisel doesn’t appreciate such boorish behavior and will bite back.

I don’t know about you, but I don’t wear thick leather steel-toed work boots in my workshop. I prefer flip-flops or crocs without the heavy and dreadfully unfashionable steel accessories. The problem is that flip-flops are not tough enough to prevent a 200gram atsunomi falling cutting-edge-first from a height of 70cm from severing a toe, so I am careful to not give Murphy the opportunity to place his bomb sight on my “little piggies.” I encourage you to always be aware of both Murphy and pernicious pixies and never put yourself at their mercy.

The solution? Be careful of where and how you set your tools down and make good practices a cast-iron habit. Don’t leave them hanging over the edge of your workbench, or balanced on top of other tools where a bump from a strolling bench kitty or vibration from a hammer impact might knock them off. If you have several chisels or knives on your workbench at the same time, use a chisel box. Another effective solution is to make a tool rest by cutting some notches in a stick of wood, place it in a safe location on your work surface and rest the tool’s blades in those notches to keep them organized, to protect their cutting edges from dings, and most importantly, to prevent perfidious pixies from pushing or rolling tools off your workbench and Murphy from dive-bombing your wiggly pigglies. This is especially important if children have access to your workplace or you have curious kitties swanning around demanding snacks and ear-rubs.

How to Develop Good Safety Habits

Everything we have discussed so far is only hot air and electrons unless you manage to actually ingrain wise safety habits into your soul. I don’t know how it works for you, but the steps below work for me. Whatever it takes please develop good, engrained safety habits.

Step 1: When you have an accident (and you will), stop working and figure out how it happened, and what you could have done to avoid it. Hopefully it won’t be while waiting for X-ray results after an iron worker drops a bunch of steel decking cutoffs on you from 14 stories above (that really hurt and destroyed a perfectly good hardhat).

Step 2: Every time you find yourself in a similar situation, stop and consider if the same bloody thing could happen again, and what you need to do differently. For instance, figuring out a clamping arrangement that keeps your left hand out of the path of travel of a bloodthirsty paring chisel is something worth taking a few seconds to do.

Step 3: Remember the pain and embarrassment of the original accident to help you make the process of thinking through potential ouchy incidents, and then using the solutions you developed automatic. In this way a good habit is born.

I can also share a personal superstition with you. Everyone nicks themselves occasionally when using sharp tools. I know I do. When this happens, I place a tiny smudge of the red stuff on the tool that bit me, and on any other cutting tools that have yet to nick me, and let it dry. I’m pretty sure this quashes their curiosity about how I taste in advance. At least I think that’s what they tell me when I am wearing my brightly tinkling metallurgical psychologist’s hat (ツ)。

There is one thing I can promise: you will find a severed tendon or damaged nerves in a hand or foot to be more than just inconvenient. And if, like me, fashion is your life, scars may tragically preclude your picture from ever appearing in the Swimsuit Issue of Sports Illustrated. Such a loss!

Be careful. Develop good habits and make them automatic. Don’t let your tools bite you or anyone else, even if they beg with those big puppy-dog eyes.


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. May all my chisels seek my blood if I lie.

Sharpening Part 29 – An Example

The expectations of life depend upon diligence; the mechanic that would perfect his work must first sharpen his tools.

Confucius

This is the final post in our series about Sharpening Japanese Woodworking Blades, in which I will try to bring all the information provided in the previous posts together into a single practical example. That does not mean the entire contents of those posts is repeated here, however, so please refer to the previous articles if things become confusing. I have provided some links in the text, and provided links to all the articles at the end.

But before we dive into our practical example, I would like to create some context.

Paying Debts

The purpose of this blog, as I have mentioned before, is not to sell stuff or attract clicks but to help our Beloved Customers increase their knowledge and improve their skills in maintaining and using the high-quality hand-forged professional-grade woodworking tools we purvey.

Another purpose is to pay a debt of the kind that can’t be recorded on paper, only in the heart.

In this series of posts I have carefully NOT promised quick and easy results, nor have I given abbreviated explanations or promoted dumbed-down techniques tailored to fit neatly within the publishing parameters of a book, magazine article, or a pretty little video. This is because the series is not about me, or my skills, or what I think is best, or selling stuff but rather helping our Beloved Customers obtain real long-term results and life-long skills of the sort expected of professional Japanese woodworkers. And since I can’t instruct them directly, our Beloved Customers must truly understand the principles and techniques so they can train themselves. Fragmentary instructions and short-cuts would be far easier to write about, but wouldn’t help with that training.

I share many experiences in common with most of our Beloved Customers, but I’ve also had some unusual experiences working with and being mentored by extremely accomplished Japanese professional craftsmen including sword sharpeners, tool sharpeners, carpenters and joiners. None of those gentlemen charged me a notched nickle for the things they taught. Likewise, I have never sought compensation for teaching others those same techniques. And so we come to the other reason for this series, namely to pay those gentlemen back for the time they spent and the kindness they showed me.

So gird up your loins, recall the information and techniques presented in the previous 28 posts in this series, and let’s sharpen a blade.

Removing Damage and Correcting the Bevel

We will not even try to deal with all the possible starting points for sharpening a woodworking blade, but in this example we shall assume the lands surrounding the hollow-ground area at the blade’s ura are already flat, planar, and polished. If your blade is not in this condition, follow the instructions at the end of this section. We shall also assume the edge has a small chip that must be removed first. These conditions will cover 80% of sharpening jobs.

Richard Kell 625-3000 Brass Bevel Gauge
Richard Kell 625-3000 Brass Bevel Gauge

If the blade’s cutting edge bevel angle is where you want it to be, the bevel is already flat, and the blade isn’t damaged, please skip to Step 11 below.

1. Examine the Bevel Angle: Check the bevel angle with your bevel angle gauge. 27.5° ~ 30° for plane blades, 27.5° ~ 35° for oirenomi and atsunomi. No less than 24° for paring chisels.

2. Correct the Bevel Angle: If, based on the check in the previous step and the blade’s actual performance, you determine the bevel angle needs to be adjusted, correct the bevel angle using your 400~800 grit diamond plate or FLAT carborundum stone either free-hand or using a honing jig like the Lie-Nielson product, the Eclipse jig, or whatever catches your fancy. If you use a honing jig, you may want to add a drop of oil to the moving parts before they get wet. Be careful to avoid making a skewed or curved (cambered) cutting edge unless that is specifically what you need.

3. Examine the Edge: Examine the blade by eye and touch. Stroke the cutting edge with your thumb (over and away from the edge not towards the cutting edge!) to confirm its condition, and run a fingernail along its length to check for defects as described in the previous post in this series. Your fingerprints will snag on any rolls or burrs, and your fingernail will detect irregularities invisible to the eye. Assuming there is some minor damage, go the next step. If there is no damage, the bevel is in good shape, and the blade is just dull, skip to step 11 below.

4. Remove Damage: Remove chips and dings from the cutting edge by standing the blade, cutting edge down, on a flat 1000 grit stone, with ura facing away from you, tilted a few degrees from vertical towards you, and pull the blade towards you without applying downward pressure. Usually one or two strokes will suffice. The goal is to remove damage by creating a flat at the cutting edge. Examine the flattened edge with eye, fingertip, and fingernail to see if the chip or defect has been removed. Repeat until it’s gone. Don’t overdo it. Whatever you do, don’t allow the blade to become skewed! This method takes a bit of courage the first time, but it is the quickest, surest, and most economical way to get the job done.

5. Clean the Blade: Carefully clean grit and mud from the blade and the honing jig’s wheel (if you use one) to prevent contaminating the next stone. This is important.

6. Check and Color the Bevel: Check the bevel frequently to confirm full contact. You might blacken the bevel with a marking pen or Dykem to make it easier to monitor progress. This step is worth repeating between stones because it is helpful in monitoring what you cannot see otherwise.

7. Sharpen on the Rough Stone: This is the most important stone in the process. Now that all the damage has been removed and the bevel is in good shape, we need to abrade the bevel until the flat we made in step 4 is gone and we have created a minuscule, tiny, clean burr. Sharpen the blade’s bevel on your roughest diamond plate or FLAT carborundum stone. If sharpening freehand, take short strokes. Always use the entire face of the stone, including corners, edges and ends as described in the previous post in this series. Turn the stone end-for-end frequently to compensate for your natural tendency to work some areas of the stone harder than others. Watch the edge carefully to make sure the width of the flat made at the cutting edge in Step 4 above gradually decreases in width evenly along the cutting edge’s length. If the flat becomes narrower at one corner than the other, apply extra pressure at the wider side, or hang the corner of the blade’s narrower side off the stone for a few strokes to correct. Stop when the flat is gone, and a clean, uninterrupted, but barely detectable burr is created. With practice, you should be able to do this without a honing jig. When using all the stones and plates in this process, keep them wet at all times, and add water as necessary. If the stone becomes dry, not only will it clog and stop cutting efficiently, but friction may cause localized heating of the thin metal at the cutting edge softening it. Remember, you’re tearing metal from an extremely thin cutting edge. You cannot see it and your fingers cannot feel it but this destruction heats up metal at that thin edge.

8. Check the Burr: Your fingertip will feel the burr long before your eye can see it. Stop when you have a small, uniform burr without interruptions the full width of the blade. Confirm this with your fingernail. Anything beyond this is just wasting metal and stones. With practice, this process will go very quickly, and you can move onto the next stone while the burr is barely detectable.

9. Create Skewed Scratches: When you have a uniform burr, work the blade sideways, or at an angle, on the stone to create diagonal scratches on the bevel removing the straight-on scratches the stone produced.

10. Clean the Blade: Wipe and wash the blade (and the honing jig’s wheel, if you are using one) to remove grit and mud. This is very important to prevent contamination of finer-grit stones. 

At the conclusion of step 10, the bevel will be flat, uniform, and at the correct angle. The flat created during step 4 above will be gone, and you will be able to just detect a full-width tiny burr using your fingers. 

For the next steps, keep the blade attached to the honing jig if you used one in the previous steps. Otherwise, sharpen freehand if you can. Don’t let the honing jig become a crutch that slows you down and prevents you from developing control.

Normal Sharpening Procedures

This is where the sharpening process normally starts when the blade is not damaged and the bevel is in good shape but only needs to be sharpened. It usually does not include a honing jig which can only slow things down.

11. Check and True the Medium-Grit Stone: You may decide to use more than one medium grit stone. I always use a 1000 grit, and often use a 2,000 grit stone as well. Whatever you use, it must be clean and flat. As described in previous posts, you need to check your stones flatness frequently with a stainless steel straightedge. To do this, wash any mud off the stone and pad (don’t rub) the stone’s face dry with a lint-free clean cloth or paper towel. Hold the stone up to a light source, place the straightedge along the stone’s length, across its width, and across diagonals to check for light leaking between stone and straightedge. Make a pencil mark, such as a line or circle, on high spots using a wide carpenter’s pencil. Once you understand if and how the stone is distorted, flatten it using whatever method you prefer, a diamond plate, a specialized truing block, or my preferred method, another stone of the same grit. If you use my way you won’t need to worry about grit contamination and can save time and money by truing two stones at the same time. Six of one, half-dozen of the other.

12. Sharpen on the Medium-Grit Stone(s): Work the bevel on your medium-grit stone in short strokes using the stone’s entire face from side to side, end to end, and corner to corner, turning the stone end-for-end frequently and being careful to avoid rocking the blade. A bulging bevel is bad news, Bubba. You will know you are done with this stone when all the diagonal scratches from the previous stone, especially at the extreme edge, have been removed. The burr may or may not have disappeared by now. Check with your fingerprints and fingernail. If it still remains, it should be just barely detectable. If it is still big, you need a few more strokes on this stone to shrink it. Using a loupe at this point will be informative. End your work on this stone by creating some new diagonal scratches on the bevel erasing all the previous straight scratches.

You may want to repeat this step using another medium-grit stone, such as 2,000 grit, to save wear on your finishing stones. Either way is fine.

13. Clean the Blade: Wipe and wash the blade (and the honing jig’s wheel, if you are using one) to remove grit and mud. This is especially important at this stage in the sharpening process. Remove the honing jig at this point if you have been using one.

14. Polish on the Finishing Stone: Move onto your finishing stone, usually a 6,000~10,000 grit synthetic stone. This may not be the final finishing stone you use. Be sure it is flat, uncontaminated with grit from rougher stones, and wet. You may want to use your nagura stone to create a slurry from the stone’s corners and edges that will accelerate the polishing process. The finishing stone serves a polishing function, and because it’s grit is so fine, it lacks the ability to distort the bevel badly, so you can take longer strokes and polish the blade on both the forward and return strokes. When all the diagonal scratches from the previous stones are gone, you are done with this stone. If there is still a burr left after the medium-grit stone, it should have evaporated by now. If not, the burr was probably too big to begin with and your technique needs refinement.

15. Examine the Bevel: Take a good look at the polished bevel. Are there still scratches left from the previous stone? This may be because you did not remove all the scratches from previous stones. Or it could be because this stone or previous stones in the series were contaminated with dust or rougher grit. If so, you should figure out why and correct that problem before the next sharpening session.

16. Polish the Bevel Using the Final Finishing Stone: This step may not be necessary, depending on the time available, the degree of sharpness required, and your inclinations. This extra polish probably won’t make a significant difference in the cutting tool’s cutting performance so is often abbreviated during a busy work day. If you use a natural finishing stone or a 10,000+ grit finishing stone, this is the time to use it. Simply repeat the process in step 14 above, but be sure to apply light pressure, keep the stone at least a little wet, and sharpen on both the push and pull strokes.

17. Polish the Ura: With the bevel polished as finely as you intend it to become, polish the ura on the final finishing stone only. Place the last 1/2” of blade’s length on the stone’s edge (the stone MUST be flat) with the cutting edge parallel with the stone’s length, and the rest of the blade hanging off the stone but supported by your right hand. Press down on the bevel with two or three fingers of your left hand. Be sure to apply even pressure with these fingers. These fingers press down only and do not push the blade. The right hand pushes the blade back and forth and onto and off-of the stone. Take light strokes focusing pressure on the extreme cutting edge, but without lifting the blade’s head.

18. Polish the Bevel (Again): After several strokes on the ura, polish the bevel.

19. Alternate Between Ura and Bevel: Go back and forth polishing the ura and bevel, but keep in kind that you want to limit the number of strokes on the ura side (assuming it’s already highly polished as discussed above).

20. Examine the Edge: Check the full length of the cutting edge frequently with your eyes, fingertips and fingernail. The burr should be gone entirely. The edge should be sharp, and absolutely smooth. All the rougher scratches from previous stones should have disappeared. I make a final sharpness test by shaving an ultra-thin slice of skin from a callous on a finger allowing my bones to sense the degree of sharpness. This method is much more accurate than shaving hair off the arm. If you try it please don’t draw blood.

21. Clean, Dry and Oil: After you are done sharpening the blade, rinse it with clean water or sharpening solution (Item 5 in Post 17) and wipe it dry on a clean cloth or paper towel. You may want to strop it lightly on a soft clean cloth (or the palm of your hand, if you are confident in your abilities) to remove hidden water. I recommend applying a spray liquid rust preventative to the blade that displaces moisture, such as CRC Industries’s 3-36 or WD-40. CRC3-36 is paraffin based, floats water out of the blade’s nooks and crannies, and leaves a film that will prevent corrosion long term. However, please note that, while WD-40 is very convenient and displaces moisture, it evaporates entirely and is therefore not adequate for long-term corrosion protection. If you are going to use the blade right away, a little oil from your oilpot is cheaper, more convenient, and will do the job just fine.

With practice, and assuming you have not let your stones become too distorted, this entire process from Step 1 should take no more than 10~15 minutes. This assumes the blade is chipped or damaged and you need to correct the bevel or use a honing jig. Honing jigs slow the process down but are convenient when using rough stones and coarse diamond plates.

If the blade is in good shape and just needs normal sharpening, the goal should be 5 minutes from the medium grit stone in step 11. If you can’t do that quickly right away, don’t rush, just practice and get a little quicker each time: Slow is smooth; Smooth is fast.

Note: If you are sharpening a new blade, or the ura needs to be trued and/or repaired, work the ura on all the stones used in the steps above, but be careful to limit the number of strokes on the rougher stones to the absolute minimum. Also, instead of keeping just 1/2” of the blade’s length on the stones, move it diagonally in and out towards the blade’s center to prevent the stones from digging trenches in the ura. Use special care during this process.

I recommend covering at least your finishing stone with something when you are not using it to protect it from contaminating dust. I simply wrap mine in a sheet of newspaper. It doesn’t take any time or money. Some stones prefer to read the sports pages, others prefer current affairs. Just ask them.

Conclusion

I am confident the techniques described in this series of posts will prove useful if sharp tools matter to you. Your tools may not talk much, but if you train yourself in these techniques I promise they will sing their appreciation.

I trust the gentlemen that taught and mentored me would be pleased with the content in this series of articles, although I doubt they have time for reading nowadays. I will ask them when I see them again in the big woodpile in the sky.

YMHOS

Links to Other Posts in the “Sharpening” Series

Sharpening Japanese Woodworking Tools Part 1

Sharpening Part 2 – The Journey

Sharpening Part 3 – Philosophy

Sharpening Part 4 – ‘Nando and the Sword Sharpener

Sharpening Part 5 – The Sharp Edge

Sharpening Part 6 – The Mystery of Steel

Sharpening Part 7 – The Alchemy of Hard Steel 鋼

Sharpening Part 8 – Soft Iron 地金

Sharpening Part 9 – Hard Steel & Soft Iron 鍛接

Sharpening Part 10 – The Ura 浦

Sharpening Part 11 – Supernatural Bevel Angles

Sharpening Part 12 – Skewampus Blades, Curved Cutting Edges, and Monkeyshines

Sharpening Part 13 – Nitty Gritty

Sharpening Part 14 – Natural Sharpening Stones

Sharpening Part 15 – The Most Important Stone

Sharpening Part 16 – Pixie Dust

Sharpening Part 17 – Gear

Sharpening Part 18 – The Nagura Stone

Sharpening Part 19 – Maintaining Sharpening Stones

Sharpening Part 20 – Flattening and Polishing the Ura

Sharpening Part 21 – The Bulging Bevel

Sharpening Part 22 – The Double-bevel Blues

Sharpening Part 23 – Stance & Grip

Sharpening Part 24 – Sharpening Direction

Sharpening Part 25 – Short Strokes

Sharpening Part 26 – The Taming of the Skew

Sharpening Part 27 – The Entire Face

Sharpening Part 28 – The Minuscule Burr

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.