Sharp vs shiny
A question that has come up amongst serious users of traditional style Japanese laminated blades is the sharp versus shiny topic. When you look at a traditional laminated Japanese blade you may notice that the different materials, the soft iron of the jigane or body material, and the hard carbon steel of the hagane or cutting edge steel each have a distinctive metallic sheen to them. Many times the soft iron backing metal looks dull and irregular in its granular composition when viewed next to the bright polished refined cutting steel portion of the blade. This contrast is found to be enhanced or even exaggerated if the blade is honed on a traditional Japanese water stone known as tennen toishi, awase toishi or awasedo.
Conversely when the same blade is honed on a synthetic manmade water stone the contrast between the hagane and the jigane will be noticeably lacking and the sheen can look uniform and shiny thus giving the bevel of the blade the look like it is all made out of one type of steel. With finer grits of synthetic abrasives the blades bevel can even look like a mirror.
Viewing the blade is simply a matter of taste or aesthetics and some tool users really like the new shiny look, like having a new car. If the truth be known, I would guess that most people do like the shiny look. But in the realm of cutting edge tools, does Shiny really mean Sharp? I would suggest that shiny can be sharp if the grit of the stone was effective in its purpose of sharpening the blade, but if the grit was not effectively cutting the steel and was instead simply burnishing the steel, then no. A burnished blade is not necessarily sharp.
This sounds like an quick answer to the sharp vs. shiny topic. But is this the end of it? Is it all just a matter of aesthetics? It has been suggested that there is another dimension which may be more pertinent and ultimately more important to the craftsperson: How long will your sharp stay sharp? And there may be a direct relationship to how sharp and how long and how shiny.
What is sharp?
To delve into this subject of the durability of sharpness let us fist define sharp.
In a rudimentary sense, the idea sharp or sharpness is when a tool; is cutting in a satisfactory manner, or as you perceive it should do, or expect it to be cutting. Simplified, a kitchen knife may be sharp enough to cut an apple but not sharp enough to cut a ripe tomato.
In theory the sharpness of a tool is realized at the convergence of two distinct planes at the cutting edge thus creating a bevel angle measured in degrees. From here on out I will be referring to this convergence of the two planes which create a single cutting edge, and not to three or more planes converging which would create a point as in the tip of a sword. In the molecular realm this convergence of two planes is measured in terms of atoms stacked into units measured as microns of width or thickness. The narrower the width with fewer atoms, the sharper the edge. For a woodcutter in a dusty shop without a microscope a satisfactory cutting edge can be measured empirically by using a certain known grit abrasive to hone an edge on his/her tool and with this tool be able to cut with limited effort a certain known material, say for instance white oak.
This known grit abrasive should have the ability to cleave off from the body of steel a particular quantity of material during the sharpening process and in doing so the grit will leave a scratch behind where the steel was removed. This scratch should represent the grit size of the abrasive while taking into account the form that the abrasive is packaged, as in: free roaming powders or slurries, or like those bound up in a solid mass like the body of the stone., In leaving a scratch "fingerprint" the full diameter of the grit particle is usually not in play in either of the above forms but instead
the scratch represents the type and size of the grit particles coupled with their abilities and effects on the blade. For instance, bound up grit in a stone may leave long continuous scratches equaling in width and depth 1/4 to 1/2 of the diameter of the actual particle as its head sits above the binder while the majority of the grit is trapped down in the stones binder. Or as if free roaming grit the scratches can look shorter with distinct entry and exit shapes where the grit gets rolled around in contact and out of contact with the steel.
Also the particular shape of the walls and bottom of the scratch can vary due to the grit particles molecular structure and its ability to, or not, retain its shape under the stress of a work load. The two most common shapes of scratches could be called the "U" shape or the "V" shape. There will of course be other variations in the scratch pattern that I will discuss later.
The question of how long will a blade stay sharp is and may be a far more practical and immediate question to a crafts person. If it can be agreed by all that; time spent at the sharpening stone is considered re-tooling or down time than the "how long" question is important. A quality cutting edge should maintain an acceptably decreasing degree of sharpness during use if the material making up the blade is sufficiently harder than the object that is being cut. In a wood shop environment it is difficult to dispute that if you are not actually in the active process of sharpening your tools, then they themselves are in the process of being dulled, and to some degree even whether you are working with them or not because simple oxidation at the cutting edge is a type of dulling action. In cutting wood for instance, a hard dull edge will stay dull a very, very, very long time. It is hard to measure dullness but we can all recognize it. But if that same blade is sharpened to a keen edge, the edge must in theory begin to dull and deteriorate immediately upon usage, even with the first stroke of the blade the leading edge nicks and folds and this is a fact that can be proven with a microscope. Although this deterioration must occur, the blade may maintain an acceptable degree of sharpness even as the integrity of the cutting edge deteriorates.
So the next question is how can we keep our edges sharp longer on the tools that we own and use. Other then changing the tool steel itself some obvious answers might be: keeping the edge protected, using the edge only on softer materials, avoiding corrosion on the edge, avoid distempering the edge, sharpening the blade on an abrasive that is appropriate for the steels composition, using a sharpening medium that will by its very nature create a longer lasting edge.
What is a Longer Lasting Edge, And How Might That be Achieved?
What is a Longer Lasting Edge? It could be in part defined as a working edge that has been boosted or improved somehow that allows it keep a working edge longer than that same particular tool had previously been known to have achieved. All tools have inherent limitations but if there is a way to enhance those limits and to create a satisfactory situation where an edge lasts longer, would this not be desirable?
And how might a longer lasting edge be achieved; Cryogenics? Micro Bevels? Altered Primary Bevel Angles? Sharpening Technique? Yes, yes and more yeses. How about our sharpening mediums and how might they affect the length an edge maintains its integrity. If one medium over another for instance, of the same grit, provided a longer lasting edge than another, might that be a simple step to take in a typical shop environment?
What Can We Buy?
When you buy a synthetic stone advertised as 1,000 grit do you assume (assume because the facts are guarded proprietary secrets) that: 100% of the cutting particles of this stone are actually graded as 1,000 grit in diameter; or could it be that only an acceptable portion of the grit particles are 1K because the manufacturer is marketing the product based on a percentage or portion (the finest grit dimension) of the mix. What percentage of the grit needs to be 1K in order for the representation to be truthful? How about the stones binder of the grit; does it release the grit particles into individual 1,000 grit abrasive particles, or do some particles remain bonded and remain together and actively cutting while floating in the abrasive slurry as mega-sized particles in the 500 grit or 200 grit dimension or larger? For a 1,000 grit stone this is not a big deal because faster cutting is usually desired, but in the 15,000 to 50,000 grit grade stones aren't we really expecting the cutting action to be in those numbers. The finer the better.
Now lets take a different approach and assume that an expensive synthetic stone of 10,000 grit is composed of one hundred percent 10K particles, this is what we were buying and this is what we got and we are happy. When using this stone the bevel of our tool is polished to precisely 10,000 grit specifications with a scratch pattern displaying 10,000 grit scratches all lined up evenly in a row. Fantastic if this is what you want. The blade will look shiny and like a 10K mirror and it will shave like ten thousand grit wonder, on the first few passes anyhow. But for how long?
Now most importantly, and this is really important, and I deferred this from above to this paragraph. Between each pair of scratches in the scratch pattern is a peak, and the peak's profile is defined by the scratch to either side of it. In using the above mentioned pure grit 10K stone as the example, the peaks will be 10K peaks because the valleys/scratches on ether side were created with 10K grit material. . Sharpening is a process of removal, reduction. In the removal process of sharpening the scratch becomes a negative space and by default the positive space left behind by this reduction is the peak. It is not the scratch that becomes the cutting edge, but the peak between the scratches is the cutting edge. Keep in mind that at the microscopic level these peaks and valleys are three dimensional. The peak is predominate and projects forward from the edge of the blade and is the first element of the blade to come in contact with the (in our case wood) material being cut *. These peaks are therefore by definition the cutting edge. As mentioned before, our cutting edge is vulnerable to becoming dull and the relationship between the hardness of the steel and the hardness of the wood is a battle of survival. Fortunately this is not a battle to the death, but just to the next sharpening, and forsaking a nail or some other hard foreign object, the dulling and breaking off of these projecting peaks is just routine and expected in the course of using the tool.
*This should be considered theory because in a practical sense a sharpened tool will possess a burr, or a folded deformed metal lip at the very edge of the blade.
In the battle to cut the wood the peak in question is being challenged to perform their duty to cut over and over again and always newer wood fibers are in play and resisting the steel. The peaks of steel by their nature of being harder than the wood, are able to hold their ground for a longer or lesser time frame that is directly dependent upon factors like the inherent steel quality, the tempering of the steel and the hardness and composition of the wood. But this is a battle and the peaks are stressed to bend down into the wood and then bent up and away, sideways and all ways. They are bent because they are irregularly angled, beveled by their very nature of being multi faceted projections. A kinetic force directed against an angle always creates resistance that is directed away from the base of the angle, an angle redirects the force away from the angle bevel. This bending creates internal stresses in the metallurgy and metal fatigue undoubtedly will be a factor in the weakening of the peaks, ultimately resulting in the breaking off of the peak's pointed end. With each successive engagement as the front running soldier peaks go down in defeat the blade is duller and requires more effort on the part of the user to engage the blade to continue cutting the wood.
Because these mini battles of engagement occur thousands or tens of thousands of times with each planing stroke, such factors out of our reach like the inherent quality of the steel of the blade and the metallurgical skill of the blacksmith are called into question.
Finally with the front line of projecting 10,000 grit peaks broken off or bent from their heroic action, charging like soldiers with sabers drawn, but ultimately yielding and failing through fatigue. The battle is soon over because behind the initial 10k peaks are not more peaks but just valleys. The stumps of broken peaks with valleys behind will not cut the wood as expected and the owner of the blade, the General, has no other option but to withdraw and go and train and re-sharpen his front line. At this stage the definition of "how long" has been established.
A Different Strategy
The battle above was quick and the woodworker/General did gain some ground, but he lost all of his troops and their effective cutting abilities more quickly then he had hoped. It wasn't until later that he realized that the battle timed out so quickly because his troops were made up of only one shallow line of attack, just one point/10k/peak deep. And that once the front/10k line was gone there was not a second wave of attack sabers moving into position to cut and gain more ground over a longer period of time. The job of attacking created fatigue and fatigue created loss and the
losses mounted up to an overwhelming advantage to the opposite side.
The General came up with a new and improved plan, his goal was to fight a longer battle and to gain more ground. And to fulfill his promise to the troops to get the job done at all costs he decided that in the next battle he would have his first wave of soldiers/10K/peaks in the front line spread out a bit more from each other and thus creating a wider and irregular profile to confuse the enemy, and nestled in between these sabers, but pulled back just a bit would be some smaller sharper "snipers/15K/peaks" ready to attack as the front points fall when the fighting gets close and personal. He knew from experience that this first line of 10K/peaks would fail and reasoned that as they did he would back them up with the small points to keep the battle engaged. The General even decided that for the heck of it he'd throw in a few larger maybe duller 5K artillery points to do some heavy lifting in the thick of it all. He figured that these larger units being not as sharp and well trained could step in and maybe plough some head way on the initial charge. His whole idea was to create a multifaceted line of attack that might confuse the enemy and therefore help to lengthen the engagement. Remember, this was his goal, to fight longer.
And the next battle did last longer, the major and minor peaks worked side by side and backed each other up and the troops only had to pull back to re-tool after gaining much ground. The General was now inspired to develop and refine his team even further. His plan was to mix in with his known size and quantity soldier/peaks a different type of peak that was created at random
This secret weapon was to be inserted into and among his troops not during the battle but instead back at base camp, when the troops were re-tooling and rallying. During the re-tooling rally the troops peaks are refined and honed in readiness, it was then that the General mixed in his morphing mixture. Remember that the peak/points are created by an outside agency, the grit, and the grit determines through reduction what size the peaks will be. The General imported (it as cheaper to import that to manufacture from scratch domestically) a type of grit that during the honing process of the soldier's peaks this secret morphing grit changes size and breaks down into smaller units through friction, some of them become very, very small. The General's hypothesis was that these smaller morphed unit grits would not only help to create little dagger like miniature 20k-30k/peaks in random formation and size to cut the enemy, but they would also help to create behind and next to and in between the major and minor peaks mini valleys with mini peaks that would help to support, through a complex geometric matrix, the actual mass of the base of the larger peaks. This matrix could in theory through triangulation support the bases of the larger peaks during stressful situations during battle engagements. Some of these mini peaks by virtue of being set back and away from the leading edge larger solder/peaks, would also be available for service to engage in cutting as the major peaks in front became dull and discarded. It was like a second wave of attack..
In battle, it is the burden of the General to accept and manage the collateral loss through engagement of his troops, but this General figured that if his troops could endure a longer battle before having to retreat and re-tool at base camp, it would prove two things for future engagements: 1) his troops were able to serve a longer stretch in the field because of the support matrix network of bigger and smaller and random peaks joining forces helping to create less down-time; 2) that because of the longer time in the field, less demand was placed on the logistics team back at base camp resulting in less frequent retreats of shorter duration for the purpose honing peak/soldiers/points and thus fewer supplies used up with less burden on the grit/room/(sharpening stone grit) support team.
A battle to remember resulted, units and battalions responded when called upon, waged over what seamed like eons but effortless, the glory and the guts pealed away like ribbons of gossamer floating upon the waifs of aromatic joys, duty served, shoulders squared in pride, the General engaged in the type of contemplation that is only bestowed upon those devoted to others but at the same time cursed with new dreams and ideas,
Soldiers/peaks are parts of a bright steel line that when primped are sharpened to cut. The General's hand helped to bring to light the random cutting strategy action needed to maintain a longer lasting attack sequence. But seeing his troops stand erect in pride filled him with a bright light of inspiration that made is heart skip a beat for he knew now what was missing from the mix. Until this moment generals were expected to order the training of the troops under his command to strengthen their strengths and join in the way as it had always been done. Seeing troops advance into battle from the right, from the left, in a V formation or as a line head were known strategies tried and true but the General saw in his mind that the random peak/soldier could hold his own and stand taller longer if they were asked to do only one job at a time, the job that needed to be done at all cost, to cut.
The General saw his troops become tired and suffered fatigue in battle partly because they were moving into battle more often then not in an angled formation, either a right handed or left handed angle, therefore coming into contact with the enemy from one side or favoring one side or the other. This works to a degree but always puts enormous stresses on the peak/soldiers more on one side then the other. This favoring of one side creates stress-fractures in the peaks inner structure, maybe too small to be seen, they did however result in the premature breaking down of the points quicker. The General could see that his next big step in the war, was to train his troops to be ambidextrous. To train them to face the challenge head on with no favoritism for the right or the left. The peaks will stress anyhow because they are angled points, but this head on approach would relieve some of the side to side bending that the peaks were suffering from in the past. From that day forward the General pledged to shape all of his peak/soldiers training techniques around the random and straight on approach. Oh how men love the dirt, as boys and as grown men, they all love to get down and dirty and with the inspiration of their general and the fresh training approach of straight on fighting, shoulder side by side, a new strength was built into the troops, and they were very difficult to put down, the General was hailed by other Generals and copied near and far in his honing techniques as a master at shaping and of sharpening.
The General, needless to say, thought he had discovered something new in the world. So after that war and the many other wars that followed were finally over, he went into business for himself. He always loved tools and he felt that he could theoretically design a synthetic sharpening stone that would mimic some of the properties that he tested out in the ways of war. There was a lot of interest in the products that were being developed by other companies in the same field, but the General took all the time he needed to produce and finalize his sharpening stone. He did make a stone that had all of the attributes of his Big/Little/Random theory, and it was a very good stone indeed. He became an industry leader, had beautiful laboratories and a sales force beyond compare and in the end decided to retire.
The General, being a contemplative man, bought an island as a retreat. He built a home but found himself more and more drawn to a cave, a natural simple cave of stone he discovered in the mountain. He was at peace with himself, he knew that he had created the finest sharpening stone that man can make, and this was a gift of creation to many. Now craftspeople across the globe, because of his efforts, could enjoy the one thing that he had always strove for his entire life, a really good sharp pocket knife. As a kid his dad had instilled in him the reasoning and pleasure
of a good sharp blade, and the General had achieved his goal as a gift to all.
Of course it was not long in that cave before the General was humbled before the rock god. Sure enough and by luck or design he happened upon a stone within his own cave that displayed unequaled sharpening powers, the kind that is of myth and legend. He found that within that simple stone were the capabilities to sharpen the living daylights out of that little pocket knife of his. Now being a humble hermit at this stage of his life, his joy was small but deep and he was still curious as to how in the world could the rock gods provide such a stone that could sharpen better than his high-tech robotic made zippidee do dad deal he got goin back home.
To make a potentially longer story a bit shorter, the General found out through deep meditation and careful observation that the secret to the natural stones abilities were not only in the Big/Little/RandomGrit part of the stone. That, it turns out, was mere child's play. The real deal was in the binder that held the stone together. The mud or clay of the stone, the binder was the real deal. The beauty of the binder was in its special ability to release the grit particles when called upon so that they could roll around and do their thing, to pick up the grit and knock it around and break down into smaller particles that might awaken other grit still bound in the rock to engage in their duties. The real magic of the stone was its simplicity. Maybe even it's irregularity.
Day after Night
I agree with The General, he did a splendid job with his developments of the past, and an admirable display of compassion to escape his ego in order to look further inside the stone that was before him. And I agree with his understanding of the magic of the stone. I have myself have felt that the element that is so perfect in the Japanese water stones are the imperfection of the binder. So imperfect are the binders, that they are elegantly perfect. Most grit will break down when forced upon itself, diamonds will break diamonds, concrete does to itself, sand crushes to sand. Why shouldn't the grit particles of a sharpening stone, either man made or natural crush into smaller random particles during the sharpening process and thereby avail themselves to create the army the general strove for, Big/Little/Random/Free. The particles rolling around crushing against themselves, the steel will aid in the crush, but it must be grit against grit and they can only do that if they are free to slosh around in the slurry and knock against each other. If they are still bound up in the binder, no go, there is no chance of engagement.
The flat shiny mirror finish we see on a chisel or plane bevel after being sharpening with a man made synthetic stone is partly an illusion. When our eye is actively scanning for the symbol of sharp on our blade to tell us it is truly sharp, the image of sharp can be overridden by a powerful mnemonic memory image that shiny represents sharp. This "flat or shiny image as sharp" begins at an early age in children, a broken mirror is sharp, a shiny knife is sharp, a shiny car is dangerous. And to a children this information burns into us the easily recognizable symbols equating flat and shiny as sharp and dangerous. As we grow older, on a casual level if our eye tells our brain that something is flat and our brain tell us that flat item can be sharp. In this way and in everyday life our eye/brain does not need to look any further, we have our answer.
In the craft world because the type of sharpness like the ultimate edge cannot be easily seen with the naked eye, these degrees or types of sharpness are at first abstract to our brain. But because through our craft we are able to recognize empirically the limits of a dull blade and or a sharp blade our brains demand that we look closer with aids like with a microscope to see the flatness of something or the actual sharpness of something and from that time forward the flash of flat before our eyes looses its symbol for sharpness as we consciously retrain our craft oriented
brains to think differently.
Is flat also a component of sharp? The answer is yes, and it is a very important but it is only one component and it only matters as far as cutting goes if the blade is flat at the very edge where the front and the back of the blade meets. And is shiny an indication that something is sharp? Yes, but only to the degree relevant to the tool an its uses. Many wood workers and tool owners are accepting these same mirrored shiny looks as a substitute or as a definition for sharp. You really need to look more closely. If a blade is shiny you need to ask if it is shiny because it has been sharpened or because it has been burnished. The business end of a cutting tool is the forward edge, the edge that first engages the object to be cut. Behind that very extreme forward edge the usefulness of the tool becomes decreasingly less important, only a holder of the edge, a handle for the edge. A mirror finish on the general bevel is insignificant. This is the night, a mirror in the dark of night is an unknown and mysterious. Catching a glimpse of yourself or someone else? A mirror surface is not sharp, it is only shiny.
Traditional Japanese laminated tool blades were designed with the expectation that they would be sharpened using natural Japanese sharpening stones. This was pronounced during the Edo period when Japan was essentially closed to foreign trade, no sharpening stones were imported from Europe or the U.S. so by default all sharpening stones were domestic. Currently in Japan you will find that active and recently retired blacksmiths are and have been following an unbroken line of traditional forging techniques that are similar if not exactly like the Edo period blacksmiths, and that many strive to achieve the same results of their ancestors. These current blacksmiths are still forging blades with the expectation that they will have a final polish derived by using natural Japanese Tennen Natural sharpening stones, the type found near Kyoto but also in other parts of Japan, are complex in their material make up and contain tens if not hundreds of different elements and compounds. Some of the minerals and fossilized organic material act as cutting and polishing agents while some make up the binder portion of the stone that holds everything together. The harder minerals like chert, a form of flint, do most of the cutting while clays mostly make up the binder. Users of Japanese stones notice the contrast between the hard steel and the soft iron after sharpening, in Japan this is called Kasumi. Kasumi is a word that describes the fuzzy or hazy look objects take on when viewed over hot summer ground. The kasumi look is desirable to most Japanese tool users but few understand how this effect is achieved.
Taking into account the hardness of these blades, in the Rockwell 60-65 range, only a fraction of the available abrasive grit mix in these stones will actually polish the hard steel cutting edge, the clay certainly will not. But conversely because the iron backing on laminated blades is so soft almost every thing in the grit mixture will affect the polish of this softer iron material, even the softer flakier grit particles.
During the sharpening process the soft iron has been honed and reduced in mass by the effects of all of the grinding compounds working in unison. The chert which cuts the soft iron like butter and the clays, salts, radiolarians and even some silica that is a know element of some of the older wrought irons will help to sharpen or reduce the jigane soft iron as it is coaxed out of the iron base. The kasumi effect is basically the result of all of these lesser abrasives working together to sort of massage the surface of the iron, none of the abrasives acting on their own to over power the other, a little bit like Judo, which translates as "the soft way". The iron is changed and reduced and sharpened, but in a soft way.
The hard tool steel takes on a polished mirror look, some suggest it has the look of chrome. This microscopic scratch pattern in the hard steel that makes it look polished has been cut by only the hardest of the hard abrasive particles and it looks regular and finished. The soft iron on the other hand looks dull and complicated. This is the contrast in the polish that is achieved with the natural stones. Synthetic stones give an over all highly polished bevel while the natural stones allow the soft iron to look soft.
At this time I can only speculate as to what materials the major brands of synthetic stones are composed of. The formulas are proprietary knowledge. I would venture to guess however that a stone advertised as a ceramic stone is basically composed of just that, ceramic material & some fancy glue or a fused binder. No one is bragging about Rare Earth Elements or titanium or some other exotic formulas. I would think that the cost factor goes way up with a more complex addition of materials, and the way the synthetic stones work now suits most users up to a point. So
no need to change. Right.
In closing, I want to go back to the mystery of it all. Mystery to me does not mean secrets or devious plans or something that cannot ever be understood. To me mystery is a grey theme, some of this and some of that. Maybe something that is better left unknown, it is more fun that way and gives us all something to look forward to. Speaking of atoms and chemical makeup and the ultimate edge is just part of communication. But our tank of talk fills up pretty quickly. I want to tell you one last story.
Outside of Kyoto is a small town that you can easily get to by a local train, and within a stones throw of the station is the workshop of Hitomi Hideo.
A soft spoken man of forty five or so who has just within the last half of his life taken up the trade of his father and grandfather. Hideo-san did go to college, and used his degree successfully, but it was not until he returned home to work again with his father that he saw the grey light.
As a teenager Hideo-san worked with his father at the mine when he could, but never really liked it or thought much of it, hard dirty work it was and of course he had other things on his mind. But as a thirty something adult he came back and worked again with his ever aging father in the mine and workshop. Still the work was dirty, that had not changed, no it was Hitomi-san who had changed. He found himself one day performing the same work his grandfather as did his father who was now showing him how to do it. Hitomi-san told me that sometimes now he goes quietly into
the stone room at night, a massive dark ever cool room that holds raw stone that was hand stacked by his father and grandfather. He will pick up a slab and realizes at that moment that he holding something so unique in all the world that he actually shakes with excitement. Fifteen years ago if anyone had told him that they would have or have had this kind of empathy about a piece of stone, he would not believe them. But now he knows what his father and grandfather saw in the grey light of the mine.