Here I will try to answer some basic questions about knifes and knifemaking.
Balance - Refers to how the weight of the knife is distributed along it's length. Generally a knife will balance at the guard or at the forward edge of the handle. A chopping knife may intentionally be made with the balance point farther back in order to distribute more of the weight in the blade. Distributing more weight in the handle make for a "quick" and more maneuverable blade.
Blade - Everything in front of the handle or guard. Blade length is measured from the tip to the guard halfway up the blade.
Blood Groove - A groove or recess cut into the sides of the blade. A common misconception is that the purpose is allow blood to drain down the blade or to prevent suction when withdrawing the knife from an animal or enemy. See "Fuller" for the actual function.
Bolster - A piece between the blade and the handle. Primarily a decorative piece, it also serves to help balance the knife. In some cases the bolster may be shaped in such a way as to also serve as a guard.
Butt Cap - A piece attached to the end of the handle. Usually made of steel or brass, it's primary purpose is to help balance the knife although it can sometimes also be used as a striking surface.
Choil - A recessed portion of the blade just in front of the guard or handle. This allows sharpening the entire length of the cutting edge. The choil can sometimes also be used to "choke up" on the knife by placing your forefinger in the choice for more control of the knife.
Clip - The downswept portion on the leading top edge of some blades. Sometimes called a false edge, it may, or may not be sharped. Typically found on Bowie style knifes, the main purpose it so bring the blade to more of a point of penetration.
Edge - The cutting edge of the blade.
Fuller - Sometimes mistaken called a "Blood Groove", a fuller is a groove or recessed area on the sides of the blade. The purpose is to stiffen and lighten the blade.
Grind - The part of the blade that has been ground to a cutting edge.
Guard - Separates the blade from the handle. The purpose is to keep your fingers from sliding onto the blade. In the case of a fighting knife, it may also serve to prevent your opponent's blade from striking your hand.
Handle - The grip portion of the knife. Handles are typically 3 1/2 - 5 inches long on a fixed blade knife to allow a full grip. Handles can be made from a wide variety of materials and attached in a variety of ways.
Hilt - Everything behind the blade.
Pins - Used to attach or secure the handle to the knife.
Primary Bevel - This is the angle ground from the spine or flat portion of the blade down toward the cutting edge. There may, or may not, be a secondary bevel right at the cutting edge.
Ricasso - The unground portion of the blade between the cutting edge and the guard. This maintains this portion at maximum thickness for strength. This is also where the makers mark is usually found.
Secondary Bevel - The angled grind that leads directly to the actual cutting edge. The reason for grinding a secondary bevel is to thin the steel at the cutting edge for a finer, sharper edge without weakening the blade by thinning a larger portion of the blade.
Spine - the unsharpened top edge of the blade.
Swedge - Similar to a clip or false edge, it is a ground portion on the top edge of the blade.
There are several basic types of grinds use on knife blades. Some styles are better suited for specific purposes than others and people will argue all day about why their preference is the best. The truth is that if one style was the best for everything there wouldn't be any other styles.
Knives are used for a variety of jobs and most types of grinds will perform suitably for most tasks. Some may perform a specific task a little better than another but basically they will all cut provided they are kept sharp.
There are many ways that a knife blade can be ground but most knifemakers today use belt grinders for speed, consistency and efficiency.
Here are some common types of grinds. Bear mind that this illustrates the primary bevel, or shape, of the knife and the illustrations are exaggerated. In most cases there will be a small secondary bevel right at the cutting edge (not show in this illustration) which will be a more acute angle.
I will go into a little detail about each style:
A flat grind is accomplished by grinding the blade flat against a platen or disc. This creates a constant taper from the blade edge to the blade spine.
In some cases there will be a secondary bevel at the cutting edge and sometimes not. If there is not a secondary bevel, the blade is sharpened by simply laying the blade flat against a honing stone and honing the entire surface from the edge to the spine.
Pros: Relatively easy to sharpen since you don't have to worry about the correct angle. Sturdy blade but it can be thin toward the edge.
Cons: The wedge shape can create a lot of cutting resistance as the blade must displace and push aside a lot of material as it cuts. As material is removed from the edge with use and repeated sharpening you keep moving into thicker and thicker steel as you move up the blade which changes the geometry of the cutting edge.
A convex grind gradually tapers to the edge in a gentle arc. Although there are several ways to create a convex grind, a common method is to grind on the unsupported "slack" part of the grinding belt. The belt will give a little and conform to the convex shape.
A convex grind usually will not have a secondary bevel as the primary bevel simply carries all the way to the edge.
Pros: Sometimes referred to as an axe grind, it is well suited to heavy chopping. Relatively easy to sharpen depending on the type of steel.
Cons: Not a good slicing blade. More cutting resistance.
My preferred grind for most blades as I feel it offers many advantages over other types of grinds.
A hollow grind is created by grinding against a wheel. The blade grind takes on the curvature of the wheel.
Pros: The primary advantage of hollow grinds is that the blade's cutting area is thinner. This creates less resistance as the blade has to move less material during the cut. Being thinner also makes it easier to sharpen and it provides more consistent blade thickness as you move up the blade from wear and repeated sharpenings.
Cons: Being thinner takes away some overall strength making hollow grinds not the best choice for heavy chopping.
A saber grind, sometimes called a "scandi" grind, is very similar to a flat grind but it does not go all the way to the spine.
Pros and Cons are pretty much the same as a flat grind.
In my opinion, this grind is almost useless as a knife blade and I honestly don't know why people choose to grind a knife this way. But, they are certainly out there for whatever reason.
Pros: Can't really think of any. Might be good for splitting wood.
Cons: Makes a lousy knife edge in my opinion.
It should be noted that in many cases, a blade has both a primary and secondary bevel in the grind.
The secondary bevel is the actual cutting edge and it will usually be at a more acute angle than the primary bevel.
So which grind is the best? You could ask a dozen experts and get a dozen different answers. Some grinds are better for specific purposes. Bushcrafters who do a lot splitting and shaving wood wood for fires seem to prefer scandi, convex or flat grinds. Hollow grinds are superior for slicing as the higher wedge tends to separate the material you are cutting and expose the cutting edge to fresh material.
In the real world, a knife is often called upon to do whatever task is at hand rather than carrying a specific knife for every application. Most any sharp grind will perform most tasks. Some may perform in a specific task a little better or more efficiently than others.
Some grinds are a bit stronger and a bit more resistant to chipping or breaking due to having more "meat" near the edge. But like everything in knifemaking, there is always a trade off. One consideration is over long periods of use and repeated sharpenings, the edge geometry will change. Every time you sharpen your knife you remove a little metal and you start moving up the blade. With most grinds, you immediately start getting into thicker and thicker steel as you go up the blade and thus dramatically change the angle of the edge bevel. This would be more noticeable with a convex grind and less of an issue with a hollow grind.
My personal preference is the hollow grind. I simply feel it cuts more efficiently and maintains it's geometry better over the long haul. But then I do not generally chop wood with my knife, that's what axes and hatchets are for. I will occasionally split wood for a fire (cutting with the grain of the wood rather than against it) and a hollow grind works fine for that.
There are basically 4 types of knife handles and they refer to how the handle is attached to the knife "tang".
A full tang handle is where the knife steel runs the entire length and width of the handle. This is by far the strongest type of knife as it has more steel the length of the knife. It is also the heaviest style of knife for the same reason. Is that much strength needed in a knife? Not really. A well constructed hidden tang or push tang knife is plenty strong enough for almost anything you would do with a knife. It's really more a matter of esthetics and personal preference.
The handles are slabs of material attached the side of the tang but not completely encasing the tang. The handle slabs are usually attached with pins or screws that run into, or all the way through, the tang. Epoxy cement is often used along with the pins to attach the handle slabs, or "scales" as they are sometime called. This not only provides added strength but is assures a water tight seal between the tang and the handle material.
Sometimes liners of brass, nickel silver or colored vulcanized fiber material are placed between the handle slab and the tang. This is done for decorative purposes and really has no functional purpose.
Some people use only epoxy cement to attach the handle slabs. Personally, I don't think epoxy alone is adequate and I would not be confident that the handles wouldn't pop off. However, you should be aware that there are methods of installing slabs with hidden pins that extend into the handle slab and the tang but do not go all the way through the handle slab. Just because you don't see pins doesn't necessarily mean they are not there. Be sure to ask how the handles are attached if it isn't obvious.
In a hidden tang knife, a narrow tang goes all the way through the handle lengthwise but is entirely encased within the handle. The handle is usually secured by threading the end of the tang and screwing on a butt cap or a nut. This is a very strong and secure type of handle in a well constructed knife.
A push tang is similar to a hidden tang except that it does not run the length of the handle. Sometimes the handle is simply glued onto the tang. A more secure method of attaching the handle is to glue it AND insert a pin through the handle and the tang which will prevent the handle from coming off if the glue should fail.
Slab handles, or "scales", are basically the same type of handles as used on a full tang knife. The difference is how they are attached to different types of knives. On a full tang fixed blade knife, the handle slabs, or "scales", are generally attached with pins that go all the way through both handle slabs and the tang. On a folding knife, the pins would go through one handle slab and one side of the knife frame or liner.
I know, I said there were 4 basic types of knife handles but then I list 5. Well, a sub-hilt is a unique style of handle although it can also be a full tang, hidden tang or even a push tang handle. A sub-hilt is simply a secondary "guard" that would typically be between your first two fingers when gripping the knife.
Aside from offering a more positive grip, the added "guard" provides some leverage when pulling the knife back toward you.
I won't go into a lot of technical discussion about steel here. If you really want to get into the technical details of blade steel there is tons of information available on the Internet and knife forums so I won't spend the time copying it here. You can also find some more in-depth information about steel on my website here: More Steel Information
There is also a tremendous amount of discussion and debate over which steel is the "best". Every year or two someone comes out with what is touted to be the latest greatest super steel that will take a razor sharp edge and hold it forever, won't break or chip, last for eternity, and maybe even walk your dog if you ask it nicely. Just as I am not convinced that chamois obtained super powers when they named it "Sham-Wow", I don't buy into all of the hype about super knife steels.
There are a lot of very good, even great, knife steels available. There have been advancements in steel technology that lends itself very well to cutlery. Does that mean that the old 1095 or 01 carbon steels used decades ago by knifemakers like Bill Moran, Bo Randall or Bill Scagel are suddenly inferior and useless? Of course not. Thousands of hunters and soldiers who have used those knives for a lifetime can attest to that.
In the simplest terms, steel is simply iron with carbon added. Modern steels are usually an alloy made up several elements such as chromium, manganese, molybdenum, nickel, phosphorus, silicon, sulfur, tungsten, and vanadium. Each of these elements in specific amounts provides certain characteristics and makes for a specific type of steel.
You should be aware that there is carbon steel and stainless steel. Stainless steel also contains varying amounts carbon (which what makes the steel hard) and is sometimes referred to as high carbon steel. What makes it "stainless" is that it contains at least 10% chromium. Some stainless steels, such as 440C stainless, contain as much as 17% chromium along with 1% carbon. You should also be aware that ALL steel WILL RUST if not kept clean and dry. Yes, even "stainless" will stain and rust. Stainless is stain and rust resistant but not rustproof.
I happen to think that 440C stainless steel has been proven to be one of the best all around cutlery steels available. 440C will take a very good edge and hold it well yet is not difficult to sharpen when needed. It is very resistant to corrosion and is one of the toughest steels available in terms of resisting breakage. It also takes a great polish and looks great.
Be aware that there are different grades of 440 stainless steel and they are very different steels. 440A and 440B are considerably "softer" and less durable steels than 440C. If a knife is simply marked "440 Stainless" or "Surgical Steel" it is most likely 440A or 440B. The more expensive and higher quality 440C will almost always be marked or advertised as 440C.
That is not to say that 440A or 440B are bad steels. 440a is the most corrosion resistant of the 440 series steels and is a good choice for a diving knife or one that will be exposed to a lot of salt water. 440B has been used by Randall knives for years and they have certainly earned a reputation of great knives. Many factory knives are made from 440B stainless steel.
Any of many good cutlery and tool steels will make a great knife and perform very well provided that the knife has been constructed well and the blade has been properly heat treated (hardened) and tempered. Proper heat treatment is absolutely critical in a knife and each type of steel has a very specific procedure for hardening and tempering. It can literally make or break the knife
Another note about hardening steel; there is a misconception among many that the harder the steel, the better. I have read many postings where someone was touting how great a particular steel was because they could get it extremely hard, sometimes up to Rockwell 62 or higher. As steel becomes harder, it also become brittle and very hard to sharpen. I believe that the optimum hardness for a knife is around 57 Rockwell. A good steel at this hardness will take and hold a good edge, be flexible enough to resist breaking or chipping, and be relatively easy to sharpen when needed.
I also want to talk a minute about sharpness. Many people want their knives "razor sharp". Do you plan to shave with your Bowie knife? Think about a razor blade. Yes, it is very, very sharp. It is also very, very thin, will break easily and dulls after cutting whiskers a few times. Is that really what you want in your knife? I grind my knives to a "working edge". It will be very sharp, but at angle that also provides strength and durability. A large knife generally with be made from thicker steel. You simply cannot grind as fine an edge on 1/4 inch thick steel as you can on a blade 1/16 inch thick. Bigger, heavier knives are usually called upon to do heavier work and therefore need a stronger, more durable edge.
A good knife is always a balance between hardness, toughness, durability and sharpness.
I will make a knife from whatever steel a customer wants and is willing to pay for. Some of the "super steels" can be very expensive. A bar of CPM S90V steel costs me 4 times as much as an equal size bar of 440C stainless steel. 440C is well proven to be an excellent knife steel over many years of field use. So, is CPM S90V so much better that it is worth paying 4 times the price? To some, yes, and to others, no.
My personal preference and recommendations are:
440C stainless steel - In my opinion, the best all-purpose, low maintenance, reasonably priced knife steel available.
D2 tool steel (very hard, almost stainless)
1095 high carbon steel (if you are willing to keep it clean and oiled to prevent rust)
Brad Vice's Alabama Damascus steel (416 layers of 4 types of steel)
I have also used some Sandvik Swedish steel with very good results.
I feel the need to spend a minute on Damascus steel. "Damascus" has in modern times become a very general term applied to any layered steel. The name Damascus originally comes from cutlery steel made in the vicinity of Damascus, Syria as early as 900 AD by master cutlers using unknown materials and methods. What we generally call Damascus today is layers of different types of steel forge welded together and usually folded several times to achieve many layers. This may be many layers of high quality steel masterfully forged by an expert or it may be layers of whatever somebody had handy and decided to try forge welding. The point is that "Damascus" has become a general term and not all Damascus is the same just as "steel" refers to many different types and quality steels.
One last note about steel. I often hear stories about some knifemaker who makes "great" knives from old truck springs, saw blades, files, or even, as one person told me, engine blocks (which happen to be cast iron, not steel). There is a nostalgic and romantic attraction for many who picture the smithy hammering a masterpiece from an old leaf spring. In fact, many such materials were good steel and many good knives have been forged from springs and files. BUT, in many cases you are dealing with unknown steels. If you are not certain what the components of the steel are, there is no way you are going to be able to optimally heat treat it. Also unknown is the purity of the material and the stresses it has already endured since it was manufactured. In my opinion, it is better to use a known steel, of known composition and properties, and manufactured for a specific use in a controlled environment.
Mirror polished means that the blade has been sanded and buffed to a high shine, removing all scratches and sanding marks. Some steels takes a better mirror finish than others. 440C stainless steel takes a great shine while D2 tool steel remains a little cloudy even when mirror polished.
Mirror polishing seems to be another one of those love it or hate it things. Not many knifemakers do it as it is a very labor intensive and dangerous process. The buffing wheel is actually the most dangerous piece of equipment in a knife shop. A buffing wheel can snatch a knife blade out of your hand and throw it back at you very quickly with deadly force.
Mirror polishing does provide several advantages. The super smooth surface greatly reduces cutting resistance. It also much easier to keep clean as it tends to shed dirt, water and corrosives. Collectors will generally argue that it increases the value of a knife.
The finish is sanded smooth with finer and finer grits of sandpaper. How smooth depends on how fine one goes with the sandpaper. Sanding to 2000 grit provides an almost mirror finish while 120 to 600 grit makes more of a sating finish. Another popular method today is the use of "Scotch Brite" belts and wheels. This is the same fibrous material as used in pot scrubbers and it makes a nice satin finish.
Bead blasted blades are actually blasted with abrasive material under high pressure in a special blasting cabinet. There are many types of abrasives ranging from sand to ground up walnut shells. A bead blasted finish is a bit rougher than a hand sanded or satin finish and is typically a non-glare surface. Some prefer it because it helps hide scratches and surface imperfections. However, the tiny pits created by the bead blasting can trap corrosive dirt particles.
There are numerous types of coatings that can be applied to blades and varying opinions about how well they stay applied. I do not coat blades.
Knife blades are typically ground from steel anywhere from 1/16 inch thick for a small pocket knife up to 3/8 inch for a large fixed blade knife. Blade thickness is another trade-off. Thin cuts better, thick is stronger (and heavier). Again, it's a matter of striking a balance and personal preference.
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