The Importance Of Understanding The Properties of Knife Steel
For a novice sharpener, a person considering purchasing a Japanese Water Stone or two with the intent of sharpening his or her own knives, where to start can be daunting. Our technologically advanced world easily allows us to access the abundance of products available and our interest and curiosity forces us to leave no stone unturned. We also have access to Forums where anyone can discuss whatever they please about sharpening. Novices may view the members of these forums as experts and take every word passed along as the right path to choose.
I was one of those people once and the paths that I chose were not always the right ones. The purpose of this article is guide the good folks who are contemplating purchases and like everyone else, have a strong desire to get started off on the right path.
When I got truly obsessed with knife sharpening, I jumped onboard the forums and Youtube and “met’ hundreds of experts with volumes of advice and I pretty much absorbed all of it, I was thirsty for knowledge and driven to being the best knife sharpener I could possibly be. All I had to do was watch a hundred videos and purchase all the water stones, especially the high grit stones, 8,000 grit and above, if I did this, I was destined to be unstoppable. A decade later I realize that that philosophy was flawed and while it had no permanent impact on my sharpening ability, perhaps, If I was smarter about it, I would have become a better, smarter sharpener, sooner.
Funny enough, the solution is quite simple, we don’t need to be hampered by the choices available to us, we shouldn’t be, we should keep it simple. Think of our elders, whom many of us learned to sharpen from. They didn’t have too many choices to make, they just did what was necessary using one or two whetstones at most and there is no doubt they made their knives and tools sharp, very sharp with the products they owned, the ones they didn’t fuss about. It was more about technique and knowledge than brand names and magical sprays for strops for example and other often unnecessary items.
I realize of course that most folks who are kind enough to be reading this have already started off on their journey but it’s not too late to listen to a man share what he learned over a couple of decades and one can learn from mistakes, one must learn from mistakes, I have learned much.
#1 Mistake: Not Understanding The Properties of Steel
The number one thing I wish I did differently was to learn about the properties of steel sooner than I did. Now when I started, there were no computers and at that time I didn’t think too much about anything other than just getting a knife sharp, not the science behind it or why it was getting sharp or dull. Later on in my sharpening life as I discovered sharpening forums, I was lured into purchasing every possible water stone in every grit that I could imagine. At that time, I incorrectly assumed that unless I had it all, I couldn’t get my knives sharp enough.
What I should have done was study steel and read as much as possible about how knives are made and what they are made of because ultimately, the properties of steel can play a major role in your sharpening results and you should know something about how different steels react to different water stones, in particular the grits, the particle sizes, if I knew then what I know now, I would definitely have become a smarter knife sharpener much sooner.
I know that checking out steel on the internet or in a book is not as exciting as picking up a knife and 8,000 Japanese Water Stone and trying to sharpen it, but remember, this article is about attempting to pass along some things that will make one a better sharpener, or at least, a more confident sharpener and confidence is a crucial element to have when learning something new. The book in the picture here called “Japanese Kitchen Knives Essential Techniques and Recipes” has a wealth of very cool information that is very easy to understand and is enjoyable to read. Think of it as your sharpening homework, it will motivate you and give you the basic understanding of certain steels and knives and that is all you need, learn this and all else will fall into place in an order that will enhance what you are striving to achieve. You can learn everything you need about steel very easy on the internet.
What is important about steel you could ask and how does that effect the way I sharpen?
First of all, your technique, whichever one you choose to follow is not greatly impacted by the varieties of steel and in many cases, you won’t be faced with many varieties, you’ll be sharpening your own knives only and the steel isn’t changing. However, it is still important to understand some basic fundamentals, how different knives (steel) are impacted by how you sharpen.
This basic knowledge of steel could guide you in your choices of Japanese Water Stones, what if you don’t have any and you want to get started, how do you choose?
As far as brands go, your interest in the subject is going to drive you to the internet and you’ll find, very easily, the common brands of Japanese Water Stones, the synthetic stones that are excellent. Yes I do realize that you could choose oilstones, that is fine, I just don’t have a lot of knowledge or desire to use them, I am stuck on water stone, absolutely stuck. Brands like Shapton, Naniwa, King, Suehiro will all be there and I don’t think you can go wrong with any of them. There are many many more, don’t get hung up on a brand, choose one and then decide what grits you want and need. Do you need a 10,000 grit Naniwa Professional water stone? Probably not but lets talk about it. Eventually, as your skill improves you will feel compelled to purchase more stones, that is fine, it’s natural, enjoy it.
I will assume you have some basic understanding of how to sharpen a knife and maybe you have even read the article I wrote on how to sharpen using Japanese Water Stones. What does the steel have to do with grit choices?
This is just basic and good to know information, it may help you choose what is the best start in grits. So lets say you want to sharpen using Shapton Glass water stones, you made a choice on the brand and now you need to decide what grits to choose from, there are many choices. from 120 to 30,000 in that brand alone, but you don’t need them all of course.
If your knife is an average Henckels or other German knife, or just the average kitchen knife that is made of stainless steel and one that cost anywhere from $30.00 -$150.00. Your knife is like most other peoples knives, nothing wrong with it, you just want to sharpen it.
Why not just break the knives and the steels used to make them into two categories, soft steel and hard steel with your average knife being soft. Steel hardness as you know can be measured very accurately using the Rockwell Hardness Scale and the quality of knives is often based on the steel used to make them. Of course other things can come into play like who made them, the handles on them, custom handles will add to the price but the steel itself is the important part. Softer steel can go from 52-56 on the Rockwell scale and you should know that every increase in numbers on this scale represents a very significant increase in hardness. Hard knives are beyond the 58 range and go up to 66-67 and again, the steel in this range is extremely hard and of course, more expensive. Knife makers cannot simply turn up a dial to increase steel hardness, there is a limited number of Blade Smiths who have the ability to work with steel at the level of hardness and perhaps have no desire or need to make their knives that hard. There is a balance between hardness and brittleness that has to be weighed, a very hard knife can be harder to sharpen, it can be prone to chipping and is more expensive and difficult to make. (Note that there are many different scales that have been created to test the hardness of steel, not just the Rockwell scale but it is the most common one mentioned).
The different types of steel, knowing them can be staggering, but again, we can keep it simple. Steels in knives are created by adding an assortment of elements to the iron such as chromium and vanadium, all of which impact corrosion resistance, hardness, toughness, edge retention, wear resistance. The makers of knives add these elements to basically make knives viable in today’s world, without Chromium they would rust for example. There is a trade off however, an extremely hard knife will hold it’s edge longer but could be prone to chipping and difficult to sharpen.
This may not mean a lot when you open your kitchen drawer and pull out your Henckels chef knife that has been there for five years. You’re not going to be able to change the properties of that knife steel but you should know at least that is considered a softer steel (It doesn’t mean a bad steel, just softer for example than the Henckels Twin Cermax with it’s incredibly hard 66 steel.)
What does this all mean to a sharpener who basically has to deal with soft or hard steel, or maybe just one of those?
Educate yourself on the steels, it is pretty interesting and easy to find volumes of information. This will allow you to choose a better knife for example, let’s say you go into a store and see a Henckels set of knives, an entire set with a wooden block for $75.00. Your basic knowledge of steel will immediately allow you to know that these are not great knives, edge retention will be poor, the steel will be soft but they will be easy to sharpen and with the right skill, your skill, they can get sharp. You just now know that not all knives are equal, not all Henckels for example are equal. Not everyone has the same budget so this is fine, but now you know.
Of course your desire to learn about steel will uncover terms like Blue Steel (Aogami) and White Steel ( Shirogami) the steels associated with handmade Japanese knives and yes, these are among the premium steels, often quite hard, 62-65 and they make wonderful knives, dream knives. ( The colours come from the labels used to label the different steels, i.e. blue paper for aogami steel 🙂 )
Again, what does all this have to do with how you sharpen?
I think it is sufficient to understand that softer steels, our average knives do not have to be sharpened at grit levels beyond 1,000 or perhaps 2,000 grit. It took me a lot of discovering to understand this but I will do my best to explain: The sharpening that you apply to the primary edge of a knife will and should have an effect on the secondary bevel, the area directly behind the primary edge, the sharp part of the knife. This area supports the primary edge which occupies an extremely thin, microscopically thin area of blade real estate. Basically, if you grind away more metal then necessary in that knifes support area, you will negatively impact edge retention.
Knife edge sharpness can and should be achieved at the coarse stone level, from 320 to 1,000 grit, this is where your going to get your knife sharp. Don’t think you won’t be able to get your knife sharp if you don’t have an 8.000 grit stone. If all you have is a 1, 000 grit water stone and all you are sharpening is an “average” stainless steel knife then with practice, that knife will get sharper than you can possibly hope for. You can still refine the edge with the 1,000 grit stone by varying your pressure, using ever decreasing amounts of pressure to refine your original burr forming strokes. You used maximum pressure to achieve a burr on both sides and then you used decreasing pressure to remove the burr and clean the edge, until your final edge strokes are exceptionally light. (You can get great knives sharp with a 1,000 grit stone as well of course)
What if you went and got a set of coarse, medium and fine stones and want to use them all? Go for it, but now you know that everything you do to the primary edge impacts the secondary bevel but you can still use your 5,000 grit stone. Just use extremely light pressure, you don’t want to use burr forming pressure, you want to use refining pressure which is extremely light and is simply used to “clean the edge”. Knowing this know though could help you if you are just starting out. Don’t feel pressured to go out and get that 6,000 or 16,000 grit stone.
For me, the most important stone is my coarse stone, this is where I make the knife sharp and as I discussed in my article about using pressure, you can still refine the edge with a coarse stone a little, you can manipulate pressure and make it work for you.
As far as steel goes, if you have a harder knife, 60 and up you can finish it at a higher grit level, the steel is hard enough to take a higher level of refinement, up to 8,000 grit or even higher if desired.
To summarize, I would recommend having a basic or intermediate understanding of steel and how it impacts edge retention and how it effects sharpening. Naturally your budget is going to also restrict what you can purchase. As you read the forums and watch videos on YouTube that may make you feel like you need MORE, remember that you actually only need one water stone at 1,000 grit to make your knives sharp. Your knowledge of steel and your knowledge of sharpening and what you are actually doing far surpasses your need to have an abundance of sharpening accessories. As you sharpen, picture bringing Side A and Side B together at the Apex of the knife as precisely as humanly possible and your level of precision will increase with practice and your passion and persistence. Don’t fret about slicing the top off a tomato or making impossibly thin slices on a grape, fret about technique and achieving a better edge today than you did a week ago.
In time, if your knife collection grows from everyday knives to dream knives, then you can dream about that 8K water stone and understand that because my Fujiwara is created from harder and better steel than my $50.00 knife, I can use a higher level of refinement and still enjoy good edge retention.
It’s a lot of fun purchasing water stones and using different grits and learning about the different feedback that a 320 grit stone delivers than a 5,000 grit stone delivers. You will enjoy this more if you have a good foundation of sharpening knowledge which starts with Steel and that is an easy lesson to learn. There is so much great information out there and you don’t need to understand it all, just knowing what steel hardness is and how it varies is a great start. I have no intention of advising you to put all your higher grit stones away because you are making your knives dull faster. All I would like is that you understand the importance of the knowledge of steel and how it is effected by different levels of grit. Once you understand it, do what you like, you can hone you knives as you see fit, but now you are powered with the knowledge that you $120.00 knife with the 8,000 grit finish got full faster than the same knife with the 1,000 grit finish. Of course this is all relative anyway, edge retention is effected by so many things that I cannot tell you that the 1k edge is going to improve edge retention. It all goes out the window if a glass cutting board is used for example or the edge is slammed with steel hone every two hours. This is about gathering knowledge and then using it as necessary. Another important and pretty obvious lesson to learn is that angles should be adjusted for certain steels and again, you can keep this pretty simple. You can have your everyday angle for everyday knives, the ones you sharpen at 20 degrees per side for example or as close to that as your ability allows you to achieve. (Strive to gain the ability to sharpen the entire blade on both sides at the same angle, whether it is at 17 or 20 degrees per side, build your muscle memory at that angle for that everyday knife). If you throw a Masakage or Fujiwara into the mix you should learn to sharpen at a different angle, your dream knife angle of 12 deg per side. These knives will come to you like this, if you sharpen it at 20 deg per side, you are robbing your knife of much of it’s cutting performance. Unleash the slicing beauty of these knives by sharpening them at a more acute angle. Therefore, you build muscle memory for two angles, the average knife angle and the dream knife angle. Don’t let a fear of angles hamper your desire to sharpen a knife, if it is 15, 17 or 19 degrees, as long as it is one of those numbers for the entire blade you’re going to be happy.
Thank you for reading this, I enjoy sharing what I can, there are folks out there with a much better understand of steel, and it’s impact on edge retention. I think of Mr. Murray Carter for example, a three dimensional sharpener, he can make the knife (dream knife), he can sharpen that knife (extremely well) and he can use it properly, he’s a genius in the knife world, I recommend learning from him, you’ll enjoy it.