Some wisdom:

Look, there are many good knife steels out there. When sites and discussions go on and on about steel types and properties, ad nauseam, they are often ignoring balance, fit, finish, geometry, accessories, service, and design. Don't get distracted by steel property details! The steel is just the start of the knife, not the whole. If it were, every knife maker in the world would be out of business, not buried in back orders and very expensive projects. When you see this type of site, ask to see their knives. That will tell you a lot!

Where did the knife blade come from?

    Homo sapiens has been around for about 100,000 years. Surprisingly, he was not the first knife maker. Evidence shows that the recently identified hominid species, A. garhi, was a tool and knife maker, deliberately selecting and modifying specific raw materials in a sophisticated and consistent way, and with careful intent. He was making double-edged knives about 2.5 million years ago. This technology gave its inventors an astonishing advantage - the ability to shift to an energy-rich, high-fat diet which led to all kinds of evolutionary consequences.

Millions of years have passed since man first noticed that a sharp flake of obsidian, flint, or agate could cut. No one knows when the birth of the cutting edge took place; it is enough to understand that the knife was man’s first tool. No image, figure or shape would carve his destiny so profoundly, and even today every item and component of everything we touch, eat, wear, or drive has at one time been touched by a cutting edge. We humans, without fang or claw, will always require our essential edge, and are simply naked without it. We are a creature that cuts and shapes things: our food, our clothing, our shelters, our very environment and attitudes are based on our ability to create, and that ability's first and foremost tool is the cutting edge.

The origins of the word knife are from the Middle English (450-1150 A.D.) word knif and knyf,  from the Anglo Saxon word cnif.  Who knows what a knife was called before that! The origin of the word blade is similar, in Middle English it was blad and blade, from the Anglo Saxon word blæd, which means a leaf.

What Constitutes a knife blade?

In our modern definition, to cut means to penetrate with an edged instrument, divide or separate with an edged tool, shear, incise, or sever.  So what is the common factor here? It's the cutting edge. A knife is used to cut, rather than abrade. Sandpaper and grinding wheels abrade, though in a way, they cut; they use tiny cutting edges (when new and sharp) to rip away small particles of surface material. An axe blade uses a bit of cutting force and a lot of wedging to split away the grain of wood. A lathe tool or drill bit uses a heavy, thick cutting edge to displace and separate metal from metal (at high speed) as a cold chisel would. Probably the largest difference between the knife and all other cutting edges is the ability of a knife to have a very thin cutting edge, with the potential to apply a tremendous amount of force behind the edge with only the power of the human hand. Though many modern tools used in industry are called knives, this text only refers to those held in the human hand.

How important is the handle?

Very. Learn more about the handle on the Custom Knife Handles page here.

How important is the shape of a knife blade?

The shape of a knife blade, to a large extent determines the absolute use of the knife. Humans have made knives for millions of years. These are our most evolved and revered of tools. We've had millennia to define, refine, and perfect the knife blade, and yet there are thousands of designs. Why? (See my own 340+ designs here) Because, as simple as it would seem, a tiny variation in length, curvature, profile, thickness, and grind changes the knife completely. It's funny how just .03" of difference will make the knife blade look entirely distinctive.  People notice this. I believe that man has made the knife for so long that it's possible that the pattern is something recognized on a genetic level. People relate to knives that way. Handles notwithstanding, I've seen clients stare and compare and tune and modify the pattern in the slightest way to reach that perfect shape that they think is just right. Where does that come from? Have they really used knives that much to be able to distinguish miniscule differences in what is right for them? There is something deeper here, something at the very core of  the human psyche. That's another discussion for my book.

In a basic way, knife and blade use can be classified by shape. A long sweeping, curving blade is usually called skinning, or fleshing, A heavy, large aggressive-looking straight blade is usually called combat or tactical. I try to stay away from the term "fighting knife," as this is a negative and unrealistic designation for a modern knives.

Many knives are classified depending on the physical attributes of their profile, such as drop point, clip point, trailing  point, and swage. Here are some classifications of knives based on description of both use and blade shape.

Knife Blade Shape Classification

Knife Use Classification

What's wrong with factory knives?

I'm in this business to make the best knife I can for your money.

Factories are in it to make the most money they can for the cheapest product.

I've read here on the internet that I'm hard on factory knives. Is it being too harsh to reveal the truth? Perhaps people who defend factory knives have spent their own hard-earned money on them and feel the need to defend their purchases. Maybe they hope that the value of their dollars are well-applied, and they won't be seen as mere consumers of a mass-marketed manufactured product. But when you openly compare factory knives to knives made by well known established knife makers, you open the conversation to reveal the differences in glaring reality. The most important thing to realize is that:

I read in an Internet post once that factories excel  over custom makers because they have "quality control inspectors" and "trained metallurgists." Evidently, the guy who wrote this has never had any contact with a real production factory. Quality control in factories is a woman sitting at the end of a line, looking for a bent or discolored blade coming out of the end of an automatic tumbling machine, which is used to put the finish on two hundred blades at once. Quality control inspectors look for workers who slow up the production line, cost the company money, and are safety hazards that bump up their insurance rates. And they look for ways to make more profit while spending less on the product. No one is sitting at the end of the line with a ten-power magnifier scanning the grinds, looking for hairline cracks and uneven grind lines or a flaw in the finish.

A good custom maker should constantly examine all the facets of the individual knife, comparing how these operations and results interact with each other, improving his skill and execution on every single knife. Though he should be concerned with safety and loss control, he does not pay for or pass on these expenses to his clients. 

And trained metallurgists? Please. Knife factories do not smelt their own ore, forge their own blades, and some do not even do their own heat treating. No knife factory is going to be bothered with someone analyzing tool steels when the exact methods of steel alloy composition, heat treatment, and usage are carefully and clearly prescribed by the steel manufacturer.  These hyped-up concepts of high quality factory work are pervasive in every industry, and they're promoted by industries that want you to think that they are more than they really are. I spent 15 years in industry; you can read about my background here. I know how factories, plants, and production facilities are run. Low budget, low quality, lots of hype and advertising. Get as many units as possible of the product out the door as fast as possible with as little investment as possible. Cut corners on safety, health insurance, retirement, and quality left and right to save a buck. If you think you know how bad industry is, talk to someone who's spend 15 years there, and they'll probably tell you it's a lot worse than you imagined. They even give bonuses for workers who figure out how to cut corners! If the unions let them, that is...

You often get just what you pay for, and sometimes a great deal less. A good custom knifemaker will understand and be able to illuminate the difference and advantages of his knives and knife making skill compared to both other makers and factories. The points listed below and on other areas of this site will help you get the facts from my perspective. Some readers may disagree with my concepts and opinions, but after nearly thirty years of making fine custom and handmade knives, this is what I have learned.

Look, there are many decent factory knives, suitable for many uses. Factories have had many years to determine what makes a knife attractive and saleable, and what makes the knife buyer have loyalty to the factory. Not all factory knives are junk, just most of them. And none of them are better than custom knives by well known makers. Why do you think that individual knife makers get paid so much for their knives? If you need a cheap, junky knife to use and abuse, without concern for quality or value, you'll buy the latest popular factory knife and that will work okay for you. But if you buy knives like that, you're probably not even reading this...

Please remember this simple, clear fact: knives by custom makers appreciate after they're purchased, and factory knives immediately depreciate.

• Here's some dirty little knife factory secrets:
• They often use the cheapest steel possible to make their knives, so that their profit margin is high. The only way a company can make money is to buy their materials as cheap as possible, sell the finished product for as much as the market will bear, and pay their workers as little as they can get away with. This way they pocket all the rest, and that's called profit. Any narrowing of the margins, i.e., more expensive materials, a lower sale price, or higher wages cuts into their profit. Remember that they're in this business for one thing: profit. It's not art to them; it's not a lifelong endeavor to create superior knives and lead the field in innovation and creative application; it's about the dollar. Most of them don't really care if your knife isn't up to snuff, or fails when you need it most, or causes accidents if you slip because it won't hold an edge. All they care about is profit. Know this.
• Factories often have blades and knife components farmed out (made by outside contractors and companies) overseas, sometimes by child labor, with workers earning literally pennies a week. Pakistan, China, and Taiwan are notorious for this. This leads to unregulated materials and metallurgical alloys, ill-fitting parts, bad finishes, and questionable moral issues. It also destroys their guarantee, because foreign factories cannot be held responsible for failures. But factory knives are usually so cheap, they'll just replace a bad knife with another bad knife. That doesn't help you in the field when you really need a good knife... Well, you get what you pay for.
• There is no law that prevents factories from stamping or marking anything on a knife blade, misleading the customer to think that the steel blade is something it's not. I've had blades analyzed that are marked ATS-34 and they are not. There is no standard or law in this industry to prevent this type of misrepresentation. A factory can simply claim ignorance (since many of their blades are farmed out), or they can say that ATS-34 is their model number. But they would have to be sued into disclosure to reveal even this, an event not likely to happen. If you have a valid complaint, they'll just give you another bad knife or maybe your money back.
• Factories purposefully list stainless knife steel as Surgical or Solingen (there is no such thing), or other descriptive text that has no reference or meaning in steel technology or industry. Often, factories will create their own designation of letters and numbers that are not listed in the Machinists Guide©, AISI, or SAE designation, or any steel engineering references. Then, they'll claim it's a special steel unique to their product. This is just a ploy to sell knives; any manufacturer should be up front about disclosing the exact material and alloy components unless he has something to hide. He ought to be able to elucidate why he's chosen that particular material, what it is made out of, and why he claims it is superior. There are no secret steels in this industry. Claiming some superior steel properties is often an attempt to draw attention away from poor design, bad fit and assembly, and low quality finish.
• Factories will misleadingly list stainless knife blades as 440 Stainless, when what is important is the letter designation after the numbers. 440a is much different than 440c; 440a has significantly less carbon than 440c, barely classifying it as a martensitic tool steel. To the uninitiated, an incomplete 440 designation is a blanket that less suitable steels hide under.
• Factories mislead by using  steel designations from other countries, because a new letter and number set is intriguing, mysterious, and beguiling to the knife customer, who may want to try that new stuff he's been seeing so much in advertising. After having an inferior factory knife, who wouldn't want to use a new type of super steel? Again, focusing only on steel alloy and designation ignores fit, finish, balance, design, accessories, and service.
• Another ploy in steel designation is that of improving an existing number. ATS-34, which is a high molybdenum stainless tool steel, is rather pricey so a new alloy was created called ATS-55. One would think the 55 would be better, because of the higher number designation. But ATS-55 has less molybdenum, because perhaps the factories don't want to pay for the more expensive and better performing ATS-34. Read more about super steels here.
• Most of all factory stainless kitchen knives are made of 420 series stainless steels, which don't even classify as tool steels. They are nothing but thin, sharpened springs. They are only suitable for light duty food service. These are the steels that have given stainless tool steels a bad name, originating on cheap kitchen and service knives in the 1960s and 1970s. The origin of these cheap kitchen knives? Japan.
• Some knives are absolutely rust free, and the factories will tout this as a great feature. Usually this means that the knife is made of stainless like 316 stainless steel, which is used in industry for pipes and mechanisms that work in acids or caustics. 316 is NOT a tool steel, and cannot be hardened. It has horrible wear characteristics, and is not a suitable knife blade. It is usually used on dive and scuba knives, and left very thick. It's fine for scraping around in coral beds and sand and mud, and once in a great while cutting a line, but very little else. It does polish nicely, though.
• Titanium blades? NO. Titanium's main advantage is its light weight, corrosion resistance, and toughness. Toughness is not hardness. Titanium cannot be hardened anywhere near knife hardness, only to about 35 on the Rockwell C scale. It is not durable enough to hold an edge. It has its uses, in handles, fittings, and springs, but it is NOT a knife blade.
• Ceramics? Where did they go? There was a great push in the late 1980s and early 1990s toward ceramic blades, but they are not tough enough to resist breakage and chipping, and couldn't be sharpened, so they are all but gone. Fine ceramic-metals, cermets (used on metal cutting machine tools like lathes and mills), are too expensive and brittle for knife use.
• Factory blades are ground often by automated machinery (CNC machines), so there is no specific and accurate control of blade grind geometry following the edge profile. Sure, there is repetitive machining, but no fine finishing, and no custom or variation of styles. We'll go into blade geometry below, for this is extremely important and deserves its own section.
• Factories purposefully leave blade grinds thick in hunting, utility, and defense knives, so that the knife appears heavy and strong, and after three sharpenings and a season of use, the knife is not capable of being sharpened without blade regrinding and relieving of thickness behind the cutting edge. More on that in blade geometry below. After three sharpenings, they'll hope you just buy another knife. They know that  brand loyalty is a powerful thing. Guys will say, "I've always bought (Brand) knives, and they've seemed to work well and last a few years, so I'll always buy (Brand) knives. After all, my (Dad, Cousin, Grandpa, Buddy, etc.) said they were good enough for him."
• Factories don't really know what you need to maintain a sharp cutting edge, and they don't even send the knife from the factory with a sharp edge! In fact, most people have never even seen a knife with a truly sharp cutting edge, and are astonished and frightened when they drag their finger over one. I've seen this again and again, and it's really sad. Mostly, factories use a fine, hard buffer and light abrasive to quickly rough in an edge, then out the door it goes. But a dull knife is a dangerous knife, because you will apply more pressure to achieve a cut, and then you will slip. And a slip is a knife out of control, headed at high speed towards a soft body part. Most cuts are from slips!
• Factories are always on the lookout to capitalize off someone else's work, and attempt to copy custom knife makers, as it is custom knife makers that are at the forefront of blade design and thus the real innovators. They will often contract to use a custom knife maker's name to promote their product. 
• They use words in their name like bench or tech to gather their product under the umbrella of fine craftsmen and handmade custom work. This is because it is understood that a huge difference exists between a handmade, finely tuned, unique custom knife made by an experienced craftsman, and a piece of steel, stamped out of a sheet or cut out by an automated plasma cutter, ground on an automated computer numerically controlled system, and assembled in America (thus deserving the Made in America stamp) from parts made by little kids in Pakistan.
• Factories are limited by bean counters, safety loss control, and materials cost and availability. This effects the geometry of your knife, the shape, the finish, the fit, the feel, the balance, the materials, the performance, the cost, the reliability, and your own safety and trust of their product. All these factors are marginalized by bean counters and accountants. Remember, with factories you WILL get less than you pay for, and the guarantee is backed by a replacement of another inferior knife, and your purchase is not an investment.
• Factory knives are not investment knives. When you purchase them, they are like a car, they devalue right off the lot. They will not increase in value, not one cent. Just take a look around at a garage sale or auction; there are boxes of knives for pennies. No matter how much B.S. the factories pile on (and there is a lot of it), your factory knife will not be worth anything close to what you paid for it the second after you've handed over the money. In ten years it won't be worth a lick, in twenty a person receiving it as a gift will be insulted. Factories try all kinds of marketing campaigns to hype the value, often associating other market brands, commonly recognized causes, organizations, or styles based on popular entertainment. This is all hyperbole spewed so that the money will leave your hands and enter theirs.
• Here is the truth: sometimes you want a cheap, throwaway knife. Factories can supply these for you. Buy them at a garage sale, you'll get a lot better deal, and you'll keep more of your own money. But when you want something more, when you want a good knife, a custom knife, a fine knife, or an investment knife, there is only one group of people that can supply your needs: custom knife makers.

What about those legendary Japanese chef and kitchen knives?

This is important: I'm in this business to make the best knife I can for your money. Factories are in it to make the most money they can for the cheapest product.

We've all heard about those legendary blades. Born of the Samurai, forged from the mud of mount Fuji, quenched in the torsos of their enemy slaves. It's time some things were set straight. I don’t know of anything that has been more hyped than Japanese steel. The reason steels were folded hundreds of times was to define and clarify the grain, because they were so bad to begin with. The reasons blades were made by laminating hard steel over soft steel was because the steels used could not be both hard and tough. Read more details about that at this bookmark. Differential tempering creating the beautiful hamon lines was needed because the steel could not be both hard and tough at the same time, so the cutting edge was left hard while the spine was tempered back.

Modern tool and die steels are hard and tough, made with the best metallurgy and chemical design we know. That is why industry relies on fine modern tool steels. Ask the company that’s making a die to stamp out medical parts for a dialysis machine, machine tools to make the helicopter gears of an HH 60G Pavehawk, or shears to fabricate the sheet metal of a car. They're using high tech, high quality tool steels that have been highly refined, and double poured in a vacuum and high purity environment. Want water-resistant ball bearings? They're the best we've ever made them, and they're made out of 440C. What are the steels used to make the tough, hard, and wear-resistant dies that stamp out factory knife blades? Why, D2, 440C, ATS-34. They're used to make the dies that stamp out other blades.

I’ve got to say this, though, the steel foundries that pour these machine grade tool steels are mostly in Japan. Good old American technology, used by a foreign country, often with raw materials that we send them...and when I was a kid, "Made In Japan" meant the worst sort of cheap junk you could find.

Look, there are some decent chef's knives originating from many other countries. Please don't buy the typical hype of historic association of ancient Japanese sword smiths with modern mass production industries. There is not a descendant of a Samurai sword maker hammering out that kitchen blade in a clay-lined forge with helpers tending the bellows, quench-water blessed by priests, and weeks of meticulous hand-sharpening with rottenstone. These knives are mass produced in a factory by automated machinery.

Read more about my fine kitchen and chef's knives here.

What are tool steels and why are they used?

Yes, Virginia, there are specifically classified tool steels, and they are specifically used to make tools for the working and forming of woods, plastics, and other metals. This is the definition of tool steel (from the Machinist's Guide). They have to withstand high loads, abrasive contact, elevated temperatures, shock, stress, and adverse conditions without suffering major damage, edge dulling, or metallurgical changes.

Not all tools are made of tool steels! Tools used to cut wood, make hand saws for woods, ordinary hand tools,  hammers, chisels, and files are often made from standard steels in the AISI/SAE categories. The tool steel category is a separate group, and must absolutely be heat treated, hardened, and tempered. There are a large number of tool steels, with specific and controlled alloy compositions. Industry has created a specific classification systems for these tool steels in seven categories. They are:

• Water Hardening Tool Steels

• Mold Steels

• Shock Resisting Tool Steels

• Cold Work Tool Steels

• Hot Work Tool Steels

• High Speed Tool Steels

• Special Purpose Tool Steels

These categories are only the beginning of specific identification of tool steels and uses. Each category has sub-categories, and many steels cross over to a variety of uses. For instance, O-1 and D2, two of my favorite tool steels, are in the category of Cold Work Tool Steels. They are hardened by quenching in either oil or air, so the hardening method is not always the designator of the tool steel category. You might hear someone group metals as "oil-hardening" or "air hardening." These are NOT individual recognized categories, the specific seven categories are listed above. Hey, I didn't make this system up, it's the industry standard!

Stainless steels have a different classification system. It's unusual, because in AISI/SAE, in order to classify as a stainless steel, they must contain at least 10% chromium. But the practice in the steel industry has been to classify steels with as little as 4% chromium as stainless steels! Some steels, like D2, for instance, contain 12% chromium, but are actually in the category of Cold Work Tool Steels, not specifically limited to the stainless steel catagory. Stainless steels are one of three types:

• Austenitic grades

• Ferritic grades

• Martensitic grades

You'll see me referring to these grades in my description of knife steels and fittings I use in my own work. Generally, austenitic grade stainless steels (like 304)are non-magnetic and can not be hardened except by cold working (hammering and forging). They have outstanding corrosion resistance, and that's why I use them. Martensitic grades are magnetic, can be hardened and tempered to the highest levels of all stainless steels, and some have greatly increased carbon content in the tool steel range (like 440C).

Now if this is not confusing enough, here is the specific Designation of steels (which is separate from the classification or the category). This is the standard, held by AISI (the American Iron and Steel Institute) and SAE (the Society of Automotive Engineers), and is the coordinated industry standard of steel designation:

• Carbon Steels

• Manganese Steels

• Nickel Steels

• Nickel-Chromium Steels

• Molybdenum Steels

• Chromium-Molybdenum Steels

• Nickel-Chromium-Molybdenum Steels

• Nickel-Molybdenum Steels

• Chromium Steels

• Chromium-Vanadium Steels

• Tungsten-Chromium Steels

• Silicon-Manganese Steels

• High Strength-Low Alloy Steels

• Chromium-Manganese-Nickel Steels

• Chromium-Nickel Steels

Okay, I hope that clears it up for you! Want to know more? Pick up a copy of the hundred dollar book, the Machinery's Handbook© and the Study Guide at a bookstore or on line. There's more info in there on steel and other materials than you'll probably ever need!

Back to Topics

What about the latest new miracle steel I've heard so much about?

Whether is S30V, 440CPV, BG42, CPM(T)440V, or AUS10: you're convinced. One of these "new" steels is the answer to your knife dreams. The steel will hold a razor's edge forever, can be hammered through a steel anvil, bend 45° without breaking, never rust, weigh only a feather, pry diamonds out of raw stone, then shave your facial hair, cut the umbilical cord on your new baby, send waves of terror through aggressors at the mere sight of it, send waves of awe through fellow collectors at the mere sight of it, and preserve freedom for all mankind. Really?

I get these questions all the time. Is this latest "craze" a gimmick, or is there a real new "miracle" tool steel? If there were a miracle steel, don't you think that it would sweep the country, be used on the latest high quality military grade and medical machines? Wouldn't it be used to cut other metals on machine tools like lathes, mills, boring machines, planers, drills and other machines? Why, of course it would. So what is all the hoopla about? Pop steels, that's what. In the 1980s it was 154CM, in the early 1990s it was ceramics, in the late 1990s it was BG42, and now it's S30V. Look, they are all good steels (except ceramics, of course) and they all can make and still do make a fine knife. So why are these pop steel trends so prevalent?

Factories, knife makers, and salesmen always need something new. That is because they must continually sell the hyperbole, to generate interest in their product. Usually, this is because of poor overall product design. In knives, the fit and finish and balance and accessories are all labor-intensive high skill areas of production, and the fine "hands-on" workmanship required to make a fine finish, fit, balance, and accessories often does not happen. Factories and low quality makers then rely upon gimmicks, tricks, hype, and envy to sell their product. So, every couple years, a "new" steel hits the market and all the guys are talking about it. It's on the forums, in the magazines, and in discussions at shows. It's the future of knife making, lots of sales are made based on it, and then it just fades away as another gimmick steel name starts dripping off the drooling tongues of dealers, suppliers, factories, collectors, and makers. Read more about this and other knife truths at the heading: "What's wrong with factory knives?" above.

Though there are very good tool steels, there is no super steel. You can read more details about this on my "FAQ" page at the question: "Is there an ultimate blade?" here. My military, police, professional collectors know that with most production knives, the hype is thicker than fertilizer at a feed lot. Yes, there are some very good knives out there, made of fine steels. But more attention must be paid to design, fit, finish, balance, accessories, and service. These are what is woefully lacking in most knife purchases. This point is so important, I've decided to give it it's own page here.

Do I use these many kinds of steel? Sure, I do, but the reasonability and economy is sometimes prohibitive. Steels may prohibitively expensive to purchase, tool, grind, and make a knife with. And do you benefit from their attributes? Usually, you'll never realize that benefit, because these specialty steels were not developed for hand knives. They were developed to machine, cut, die press, and form other metals and materials for industry, usually at high feed rates, high speeds, with extreme pressures and heat, sometimes under corrosive chemical exposures. Knifemakers just pick up on them because makers like to experiment. So they find that they all perform pretty well. I even tried some M2 once to make a knife, the performance was outstanding, but the steel had ugly waves and texture in the surface. I don't know if the user ever sharpened it, because he couldn't. Only a diamond grinder would sharpen it. So there's the limitation of usability and service too. The truth is, if more factories and knifemakers improved those six points: design, fit, finish, balance, accessories, and service, they wouldn't need to hype some "specialty" steel as a gimmick. Read more about that here.

 Back to Topics

Here's an email asking for clarifications about my steel discussion on my site:

Jay,

       I have really been thinking hard about the knife I would like you to make me. I think I am almost done with the design of it. I have a few question about steels and their finishes. I read what you said about S30V steel and I think it is weird that the steel does have "even distribution of alloy elements" but yet it still chips at the edge. I went to the website of the people that make the S30V and S60V steels and of course they did make it sound like the "best knife steel ever" but I think I trust your opinion more. Why do you think the steel would still chip even though it has better distribution of the alloy elements? I have read a lot about the S30V steel on the internet and some people say that all steel chips at the edge, is this true?

Also, I really want my knife to have the best finish possible. Your chart on your website says that 440C has a "excellent" finish and ATS-34 has a "very good" finish. But, then in the section above the chart were you talk more about each steel it says that ATS-34 has a bit smoother finish than 440C. Does this mean that ATS-34 would have the best finish or 440C? Well, sorry for the long e-mail. I just really need to know so that I can pick the best steel for me. I'll be e-mailing you my design for my knife soon to see what you think, then we can go from there. Just let me know that you think. Thanks!!!

--B.

My answer:

How do I pick a steel type?

Okay, you want details. Metallurgical specifics, because you have a keen need to know just what it is that you're using, paying for, or requesting in the blade steel. Please be sure and read about the "Pop" steels above, and all of the pertinent information on the FAQ page. Then be sure and read the several topics just below this one, for some more information.

There are a great number of tool steels, and like most custom knife makers, I have my favorites. The reason a knife maker chooses a knife steel depends on a list of requirements. Often, a client hasn't even considered some of them when he starts the conversation. The word "best" comes up frequently. He wants the best performance, the best durability, the best looking. "Just give me the best steel, Jay," he'll say, and then he'll have the best knife. It's just not that simple. The knife maker must balance many things in his choices, some factors not even considered by the client. Here they are in detail:

Hardness: Any good custom maker who heat treats his own blades can produce a very hard blade out of any of the most commonly used blade steels. Hardness is penetration resistance, explained below. It is not the complete standard that a blade is defined by! It is merely the resistance to penetration, which contributes to wear resistance. A maker can make a blade very hard, but if he does, he'd also better make the blade very thick, because it will be brittle, and possibly break if stressed. But who wants a knife blade thick? Only a cold chisel is left thick, not a knife blade, because a thick blade cannot be made sharp. So the hardness has to be balanced with the other factors.

Toughness: A tough knife means that the steel is resistant to fracture. The toughness-hardness relationship is explained below, in the section "What About Hardness?" and "Just What is the Rockwell Hardness Scale?" below. Literally, it is the resistance of the crystalline structure to be ripped apart from itself, and that is how a break occurs. Of course you want a blade tough, because a break could be devastating anywhere along the knife blade. The hardness-toughness relationship is under the complete control of the knife maker, within the constraints of the steel alloy used. It is critical to make a thin blade with a tough temper, because a thin cross section must support the mechanical stresses imposed on it. It seems that toughness is completely overlooked in discussions by knife "experts."

Wear Resistance: This is the ability of the steel at the cutting edge to resist abrasive wear. What this means to the knife maker and client is that the blade can perform a great deal of abrasive cutting without needing to be re-sharpened. Contrary to popular thought, this is not solely the result of the hardness that a blade is tempered at. Wear resistance is largely due to the alloy components in the steel's crystalline lattice. Large amounts of specific alloying elements like tungsten, vanadium, and chromium all add to the wear resistant capabilities of the blade's cutting edge. When properly heat treated and tempered, the steel contains amounts of very hard particles, chromium carbides, tungsten carbides, and vanadium carbides that all resist wear. But sooner or later, even the hardest, most wear resistant knife blade WILL require sharpening, so wear resistance must be balanced with serviceability.

Serviceability is my own term, and it refers to the maintenance requirements  of all knife blades. Blades have active areas, mainly the cutting edge, the point, and the finish. All of these areas must be serviced and maintained. There are also serviceability requirements of the handle and sheath, but those are discussed on other appropriate web pages.

Sharpening: Even the hardest of knives must be sharpened, but what if the steel is so hard that it cannot be honed or sharpened by hand? The knife must be sharpened in a shop, often with a powered edge grinder and sharpener. One would think that this would make a great tool, because of long cutting edge wear resistance, but what if you're in the middle of dressing out an elk, and the knife edge has reached a point of dullness? What if you're in combat? Many times, it is more important to have the ability to bring a cutting edge to a fine sharpness whenever it's needed than to have a knife that has greater longevity in the edge sharpness, but will take powered equipment to sharpen. I've got some guys that claim no steel is too wear resistant to field sharpen, but those guys think nothing of dragging their blades literally HOURS against the stone.

Point service: The point is the most important part of the knife blade, and to be truly effective it must be thin. Therefore, the maker must balance the usability of a thin point with the intended use of the knife. The point must be cared for, and the rest of the blade will follow. If the maker has done his work right, the knife user has a long-lived blade point, one that isn't sharpened away to bluntness by a bad or thick grind. If the point is maintained in use, the rest of the blade will follow. You might wonder why I focus on the point in particular. It is because if any part of your knife will fail, it will probably be the point. Steel choices must reflect the geometry, hardness, and toughness relationship of the blade.

Finish: A lot of knife users initially want to forego a good finish to save a buck. This is possible, but once they realize that it might affect knife blade performance, value, and longevity, they usually rethink that casual attitude. A finely finished knife will simply last longer than one that is rough. A finely finished knife is more valuable in the long term than a rough or poor finish. I talk about the finish in detail on my book excerpt on this very page. The finish desired rests initially in the steel choice, and ultimately in the maker's skill. 

Cost: All fine steels are expensive, some are very expensive. Some are much more difficult for the maker to use to construct a knife, so their use in a knife blade adds to the overall cost. Certain steels may cut the life of band saw blades, milling cutters, drills, grinding belts, and finishing supplies by three to four times, and the working, grinding, and finishing may take five times as long, so the knife maker must add the cost of all these expendables and time to the knife cost. Some steels may push the knife out of the price range of the client.

Value: The value of a knife blade exists in its geometry, construction, design, and finish, and less so in the materials (I'll bet all you guys wanting the latest pop steels are surprised by that!).  Mass-producers of knives, or makers who wish to somehow try to set themselves apart and above others will often focus on the steel type, and less so on their ability to design, construct, harden and temper, and properly finish a knife blade, or make a knife that has real long-term investment and working value. The real value rests in those makers' skills, not just a steel type. A similar comparison would be one of jewelry. A five gram nugget of gold costs the same as a five gram amount of gold used in a fine ring. Which is more valuable? The value is not just the material. It is in the maker's skill, his reputation, his longevity, and his popularity. The long-term value of a knife is also based on the material's ability to retain its appearance and shape, which is related to the finish and geometry. Additionally, the value will be placed upon the knife owner's level of care for the knife. Even the most expensive knives can be neglected, rendering them of little value to collect or use.

So, to select a steel type for a blade: here are the considerations: hardness, toughness, wear resistance, serviceability (sharpening, point service, and finish), cost, and value. Seems so simple...

Hey, where is the "Strength" requirement? Read the next topic.

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What is a strong blade?

Every now and then, I read a post or article that talks about strength as a factor in knife blades. The strength of materials deals with the external forces applied to elastic bodies. When these forces are applied, deformations and stresses occur, and in extreme cases, failure in the form of bending or fracture. There are a large number of factors to consider in applied forces and metal choices, geometry, time elements, temperature, corrosive exposures, and others, which all have an effect on failure rates. You'll see the word "strong" thrown out there as if it is the all-encompassing final descriptive word to describe metals and performance.

If resistance to failure was the sole measure of a knife blade, why not just leave the blade unhardened, untempered, because that makes it the most resistant to breakage? If you have an unhardened, untempered piece of steel, you can bend it this way and that way, and stretch it, and twist it, and deform it, and guess what? It won't break. It will just deform. Eventually, it will work-harden in the area that it is most deformed, then it will become hard, and more brittle, and then it will fracture. Bend a piece of thin metal back and forth until it breaks. We've all done this; so it's easy to understand.

These same sites will claim that steels with what I consider to have a lower overall performance value as a knife blade are superior to the steels I use. You could claim that 440A is superior to 440C because it is tougher, that is: more resistant to breakage. Guess what? You would be correct! But 440A has less carbon (approx. .060%) than 440C (approx 1.2%). That carbon (twice as much in the 440C) is essential for assuring the hardenability of steels to the levels needed for tools (from the Machinist's Handbook). Raising the content of carbon increases the hardenability slightly, but increases the wear resistance considerably! Increasing the carbon content will have the effect of decreasing the toughness. So if your entire standard for knife performance and strength is unbreakability and toughness, go with the lower carbon blade steel that is not as wear resistant. But who wants a knife that you have to sharpen frequently, a knife that easily dulls? It's all about balance.

What about ultimate corrosion resistance?

Another balance question. There are materials that absolutely will not corrode. Ceramic comes to mind. Titanium is nice. 304 austenitic stainless steel is extremely corrosion resistant. So why would old Jay have stated that 440C is one of the best you can get for corrosion resistance? Because those other materials do not make good knife blades! In my opinion neither do 440A, and 440B stainless steels. These steels do have at least .060% carbon and are capable of being hardened and tempered, but are not nearly as wear resistant. One may claim that S30V, S60V, and S90V are slightly more corrosion resistant than 440C, but since they can not be mirror finished, their rough surface may actually accelerate corrosion (see my book clip on finishes below). There are a host of other metals used in knife blades and a large variety of performance options, so nothing is set in stone here. That is why any maker worth his salt will use a variety of steels, and yet still have his favorites.

What kind of steel are you "pushing," Jay?

I had a good laugh when I saw on another site that I've been accused of pushing a particular type of tool steel by self-proclaimed experts on knife blade steel. I don't. If you have a special steel you prefer, please, by all means, let me know why, and I'll make a knife out of it for you! I don't have an agenda about the steels I use, I just have my favorites. There are new ones all the time, and you might be surprised to find out that I've tried quite a few. I don't get kickbacks, or promotional payment, or some kind of benefit from suggesting a particular type of steel. I also am very clear about the steels I do use, and if you have a particular and specific question about the type of steel used in a knife I make for you, by all means, ask! Please don't ask about steels other makers use, feel free to ask them. Want to know what is being overlooked by experts arguing about steel types? Fit, finish, balance, design, accessories, and service: right here.

Some wisdom:

Look, there are many good knife steels out there. When sites and discussions go on and on about steel types and properties, ad nauseam, they are often ignoring balance, fit, finish, geometry, accessories, service, and design. Don't get distracted by steel property details! The steel is just the start of the knife, not the whole. If it were, every knife maker in the world would be out of business, not buried in back orders and very expensive projects. When you see this type of site, ask to see their knives. That will tell you a lot!

What are the steels you use, Jay, and why?

440C High Chromium Martensitic Stainless Tool Steel is chosen for it's machinability, ease of care, and long lasting value. 440C is one of the most often used knife steels in the handmade industry because flat out, it's a great steel. It is my most often used steels, and it has a fantastic reputation of reliability and value. It's one of the most stain resistant of the stainless tool steels, with up to 18% chromium and up to 1.5% carbon. Not much will corrode this blade steel, and it's tough and hard and wear resistant. No tool steel is rust proof, but 440C is about the best you can get for fine custom knives (details above). For long lasting beauty, it's the choice for most of my knives, and for nearly all my high end and sculptural pieces. 440C has and retains high investment value because of its capability to be highly finished and polished. It is a beautiful high chromium steel. 440C is used in more of my combat knives than any other of the steels I use because it is proven to work well, limit corrosion, and be strong and tough enough for combat tactical and rescue operations, yet it can be sharpened with only moderate effort. There is a reason that one knife blade analysis and testing site claims: Grade 440C is capable of attaining, after heat treatment, the highest strength, hardness and wear resistance of all the stainless alloys. They may be overstating things a bit, but nonetheless, 440C is a great steel. Just look at some of the finest knives made by some of the best makers in the world. Many are using or have used 440C. It is a gorgeous steel, with a bright bluish chrome color when polished. When you want an investment piece to have a high finish, hold it well, and hold it for decades and decades, 440C is the way to go.

ATS-34 is essentially the same as 440C, but 3% of the chromium has been replaced by molybdenum. So it's a little less stain resistant, but it's tougher. That means it's more resistant to breakage. This is one of the high "chrome-moly" steels everyone's heard of. The finish can be a bit smoother than 440C, but I've also had some that is grainy. Because of the additional toughness, a thinner cross section can be ground for blades like double-edged tactical knives, without sacrificing strength. For the knifemaker, it's also harder to work with: harder on tools, abrasive belts, and is more expensive. Being not as corrosion resistant as 440C, it may not hold its investment value for as long, but we're splitting hairs here. It should retain its beauty long after you and I are dust, with minimal care.

154CM is essentially the same as ATS-34, but is a domestic version. I don't use it because it sometimes has pockets and voids in the steel, making it unusable in the custom knife field. I've never discovered any pockets or holes in ATS-34. Other makers may argue, but I won't take a chance in working up a blade, and finding a hole in it!

CPM154CM is similar in composition to 154CM above (similar in composition to ATS34), but is crucible particle metallurgy tool steel, made of sintered alloys pressed together. It is a fine steel. 

O-1 is a highly underrated yet superb oil-hardening cold work tool and die steel and is a high alloy tungsten-vanadium tool steel that can be made tough, hard, and extremely sharp. O-1 blues well, so tactical models and art pieces that require a dark blade look fantastic. It's fairly easy to work in the annealed state, so prices can be kept reasonable. Polishing it is difficult, and different than the stainless tool steels. O-1 will flat out rust if not cared for, but it's a great steel, maintains an incredibly sharp, fine edge and is relatively easy to sharpen in the field.

D-2 is the highest carbon alloy tool and die steel (thus the "D" designation) used in knife making. It has 12% chromium so it doesn't resist corrosion as well as high chromium tool steels and will rust if continually exposed to corrosive moisture, acidic fluids (like orange juice or blood), so requires more attention. But at 1.65% carbon, it can be made very hard, and very wear resistant. The polished finish on D2 is somewhat "mottled" with an "orange peel" appearance. This is due to chromium carbides forming in the steel during heat treat, the very thing that makes this steel so wonderful (most steels form iron carbides). D-2 is very hard to work with, expensive, downright mean to abrasives, resistant to cutting and milling and fabrication. So it's usually used for extreme use knives. It has a reputation of "holding an edge forever, and being impossible to sharpen." The reputation is well deserved. Most people cannot sharpen D2 in the field, or without motorized equipment.

CPMS30V, CPMS60V, CPMS90V (sometimes called S30V, S60V, S90V, 440V): It's important to see the "CPM" designation in front of these steels when their use is claimed by makers and manufacturers. It stands for Crucible Particle Metallurgy and means that the steel components and alloys are mixed and inserted in powdered form into a die, and the steel billet is formed under tremendous heat and pressure, similar to sintering of metallic components. This allows an even distribution of alloy elements that might not be possible by traditional methods. The 30, 60, and 90 designations refer to approximately 3% and 6% and 9% of vanadium in the alloy. Vanadium is used to contribute to the refinement of the carbide structure, and thus improves the forgeability of these steels. It has a very strong tendency to form a hard carbide, which improves both the hardness and the wear properties of these steels. However, a large amount of vanadium makes the grinding of the tool steel very difficult. These steels will eat up grinding and finishing belts at three times the rate of 440c, and are much more expensive. The downside is that the price of machining is high, the price of the material is high, and the availability of sizes are limited. These steels, when properly hardened and tempered do create a very tough, very hard blade, slightly tougher and harder than 440C. So hard and wear resistant are they that sharpening is extremely difficult without motorized equipment. Sharpening may also take many steps to achieve a very fine edge, so they're not practical for knife users who might need to sharpen these steels in the field.  One of the main and seldom talked about (elephant in the living room) issues is the inability to be properly finished. Since most makers just rough grind and hand-sand along the blade length, it doesn't matter, but that is not how a fine investment grade knife is made. None of these steels can be mirror finished to any reasonable degree. When they are brought up to fine finish and polishing, the finish smears, fogs, and skids (polishing terms), and brings out waves of uneven texture. Frankly, these are ugly steels best left sanded or bead blasted. The craze over these steels is highly hyped, until a client asks for one to be mirror finished for investment value and high corrosion resistance.  I do use these steels, but they are not my most popular because of these issues.

These are the main steels, and I also use other specialty steels. I might add to this detailed description as time goes on.

Choosing

A choice of blade steel does not need to be daunting task. Since all of the blade steels I use are fine tool and die steels, all high alloy well designed engineered steels, every component, every arrangement has been detailed. You know just what you're getting, without a lot of hype and bull. So many confusing recommendations, suggestions, and so much hype is on the internet and in magazines about special steels that this has become a sore point with most knife buyers. Everybody hypes their steel, and nobody looks at workmanship, design, fit, finish, service, and accessories. Look at my "Knife Points" page here and you'll understand exactly what I mean. Most knife users will never use a knife brutally enough to actually notice the difference in performance, but of course, every knife client wants the best steel for his purpose and his money.

This chart is a general guide only, and the properties of these tool steels can be adjusted in the grind geometry, and the hardening and tempering. All these steels outperform plain carbon steels, non-tool steels, or damascus steels. As you can see, everything is a trade-off. If you want to go with D2, for instance, you will have a hard time field sharpening it, and it is very expensive, and does not have a good finish. For high art pieces and investment pieces, 440C is usually used, because of  great corrosion resistance and finished beauty. Only O-1 in this list can be hot blued, and is easily field sharpened, but it rusts at the first opportunity of neglect. You might want the tough, hard, supreme wear resistance of S30V and S90V, only to find out they can not be mirror polished, so are not suitable for long term investment knives. Corrosion resistance can be very important if the knife is used in the field of combat or tactical operations around corrosive fluids or water. Remember, the edge itself can corrode, and become dull from corrosion. This is probably another reason why my most popular knife steel is 440C.

An interesting thing to consider is that manufacturers claim that CPMS30V is more corrosion resistant than 440C. But this claim assumes that both steels have the same finish. Since S30V, S60V, and S90V can not be mirror finished, there is no way that in a bead blasted or rough satin finish they are more corrosion resistant than a fine mirror finish on 440C. Read why below. 

The chart demonstrates why  there are choices, to allow the knife client and knife maker to reach an agreement on the steel's properties suited to the application. These are only my main steel types. There are other steels, of course, and I'll add their properties as I get requests.

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Are all custom knife makers alike?

Of course not. They run the full range of quality from low to high. Some flat grind, some hollow grind, some stock remove, some forge, some assemble kits. You'd better be educated about the difference if you don't want to get ripped off. Here are some points to look for:

Is your knife maker well known and established? Unlike factories who use a name from another time when they actually made a superb product, the knife maker must establish his name over decades of production. I'm not saying that a new maker does not make a fine knife; sometimes he does, it's just that longevity in this business is created one knife at a time, over decades. A beginning knife maker or craftsperson can work for a month and produce a pretty fine knife right out of the blue (or from a kit), but that is altogether different that a full-time custom knife maker who produces hundreds of knives, every one of them superior to most other handmade knives, year after year, for decades and has the testimonials from professional knife users like the active duty military, police, professional chefs, professional hunting guides, and collectors to back it up. This is generally someone who knows knives, or he wouldn't be in business. His name is etched, stamped, or carved permanently into the steel, and every knife with his name on it carries his reputation.

Does the maker serve professionals who use fine knives daily? Does he make for professionals who trust their lives to his workmanship and product (like military in combat, police and SWAT teams, or CSAR rescue teams)? Has he done that for years? Decades? Can he prove that to you, show you his work, illustrate by commentary and testimonials? Are his knives sought out by collectors for their own originality? Do his knives increase in value over the years? Is he charging more every year for his work? If he does, and he has no inventory, it's a good bet that his knives appreciate dramatically.

Look at the individual knife closely. Is it properly finished? Does the blade have grind marks, sanding marks or waves? (More about blade finish here) Are there any visible gaps, scratches, bumps, waves, or rough spots in the handle? (More about handles here) What does the overall appearance of the knife suggest? Is the blade size in balance with the handle? Are there thin areas where the whole knife might be weak? Did the maker fully taper the tang? Is the filework or edgework accurate, balanced, and square? Does the sheath match, and is it well made? (More about sheaths and stands here) Pick up the knife. Does it feel good in the hand? Is it full, smooth, and solid? Is it balanced, easy to manipulate, and comfortable? Does it fit well and snug in the sheath? A maker should have no problem with you handling his knives, in fact, he should encourage it! I've conveniently put handles on each and every one just for that purpose...

Here's an important one: Hold the knife with the edge up, the point aimed right at the space between your eyes. Now cast one eye down one side of the blade, and the other eye down the other side of the blade. This may take some practice, but it's worth it. You'll get a clear picture of the grind lines, where the hollow grind (or flat) grinds meet the blade flats. These lines should match as closely as possible. By the way, looking at knife this way scares a lot of knifemakers, because they know you'll be able to see any irregularity, and it also shows that you know custom knives!

Is it sharp? Most people can lightly touch the thumb or finger to the cutting edge and tell. There should always be a wide-eyed amazement when this happens!

How does the buyer know the reputation of the maker?

There are several ways to verify the knifemaker's reputation. Who does he make for? He should have that right out front, for all to see. He should have no problem telling you who he makes for, what they use the knives for, what the knives are valued at. Does he have a past history of shows, membership in professional knife organizations, or publications of his work? Does he have a professional website, brochure, or catalog? Where are his knives now? Are any in museums, collections, or displays? Can he give you any names of people who have used his knives and like them? Can you see pictures of his knives?

These sound like simple, obvious questions, but you would be surprised at how many clients are distracted, played, and conned by knifemakers. Here's an example: I recently attended a show and my table was next to a female knifemaker, who immediately claimed to a prospective client that her family had thirty years of knife making experience. She was in her early twenties and laid claim to her family's experience as her own! Those years of experience were not apparent on the knives laying on her table, as they were big and blocky and badly finished and out of balance and ugly. Then, she gave the prospect some b.s. about the mystery of heat treating, how it was a special family secret handed down through generations. I bit my lip, knowing that heat treating is specifically described and prescribed by the manufacturer of the steel, that it is right up front in all engineering specifications for all knife steels, that it should be clear and simple to the client that the maker is treating the steel just as specifically as the manufacturer requests for the intended use. But the worst part is that she giggled and feigned interest in the client, smiling and flirting like a prostitute, which kept him looking at her more than the knife. The truth here is that some men are easily swayed by the attention of a young lady. He'll walk away with an overpriced hunk of junk, and the memory of a brief encounter with a con. Is it worth it? I wonder how the line of b.s. would have gone down if his wife was standing beside him-

The moral here is look, look, look.... at the knife. The knife itself should be your focus of attention. Yes, you want to know the reputation of the maker, you want to know he's had years of experience and trustworthy clients. Still, take some time and examine the knives or the photographs very closely in front of you, they should speak for themselves. Listen to what the knifemaker says; does it make sense? Can the knifemaker answer your questions with intelligence and dignity?

That brings me to another professional aspect of the knifemaker: his appearance and attitude. Do you like buying from a loud-mouthed polyester prince used car salesman? Are you comfortable with a cowboy all duded up with his  best brushed felt range hat and high boots more suited to stomping through cow dung than presenting fine work? How about that guy wearing a tee-shirt with rude graphics and holes in it and a goofy, grimy baseball cap? Are these professionals that you would hand your hard earned trust over to? The reason I include this topic is because every knife or craft show has this type of knife maker. So, does the knifemaker look, act, and present himself as a professional? Now, don't get me wrong, if someone comes to my studio and shop, and they catch me with my full-face respirator and metal swarf-covered coveralls and work boots covered in wood and rock dust, I'm still a professional. But I wouldn't be caught dead at a knife show in that get-up. It's just not professional.

Look, there is no miracle about making knives. Making knives is perhaps the oldest profession around. Yes, before even THAT one. Men have made knives for literally millions of years, for without a blade, early man would have starved. It is an honorable profession, if presented honorably. There is no great mystery, just great skill. There are no mystical secrets to steel ingredients, to heat treating, to shape, geometry, or materials. There is no enigma in the blade, we don't quench in the blood of our enemies, there is no romance to the cutting edge, only artistic interpretation. No sword or crystal has magical powers, steel can't cleave stone, and a suitable dagger will not allow you to fly. Fine knives come from trained and practiced hands, not from a hidden tomb in a mountain. They are tools and sometimes works of art made by people like me who probably love to make them. I take this business seriously; it is my full time professional job. 

What is blade geometry, and why is it important?

Blade geometry is most easily interpreted as the three dimensional view of the knife blade. Most often, the flat perspective is used in examining a fine knife blade, the same view presented in a photograph of the knife. You can see the grind profile, the general shape, the contour, and any additional agents such as serrations, clips, false edges, choils, and filework. This view, however, lacks the third dimension which is cross-sectional geometry. How thick is the knife? How thin is the cutting edge? Is the grind matched and balanced on both sides? Let's examine some of these points:

The thickness of the knife at the spine (which should be the thickest, strongest part of the knife, not the handle!) must be strong enough to support the leverage applied at any point along the knife blade within reason. I accent reason because a balance should be met between thinness of the cutting edge and the weight and thickness of the spine. For example, you probably couldn't break a blade that had a spine of 5/16" (.3125" or .8 cm) thick. But this would be an extremely heavy knife (more like an axe, actually). Now, to put a fine, thin cutting edge on such a beast would require a deep hollow grind, or a long flat grind, and for proper geometry that would necessitate a very wide blade. Some makers actually make this kind of knife, so there evidently is an interest in them, but you won't find them on my site. Mountain man knives seem to lean toward this geometry. I've never met a man that used an axe to skin a deer, but I haven't met everyone...

The most important part of the knife's geometry is the cutting edge. It must be thin on most knives: thick enough to support the intended use, but thin enough to allow a low sharpening angle for aggressive cut. So the custom knifemaker walks a balance between strength and thickness, and sharpness and thinness. Learn more about thinness and sharpness and the cutting edge by linking to "Razor Edge Sharpening" on my links page here.

For comparison, let's first examine the flat, taper, hollow, and convex grind.   Here is a view of the cross-sectional area of the ground portion of a blade.