Half way through another week. Lord time seems to fly, but that makes it Wednesday and timer another ramble about knives. So far we've looked at the steel they're made of and the style of blades you might find, so today I thought I might take a look at the grinds used in blades and how the grind effects a knife's cutting ability.
Now if you're fairly new to knives, or even if you're not but always used to assume a knife is a knife is knife; you may not know just what a blade smith means when he talks about the grind. Well no matter how a knife gets it's form, be it forging or removing excess metal until the blade takes shape, sooner or later you have to take it to a grinder of some sort to put the final edge on. That grinder may take the form of an old fashioned bench grinder, a belt grinder, or even an even older fashioned whet stone and a set of sandpaper sheets, but you simply cannot put an edge that will really and truly cut without it; and the type of grind you use can have a huge impact on the finished knife.
Probably the oldest, and still most common type of grind is the V-grind, sometimes called a Scandi grind or Scandinavian grind. With this grind, the blade is left the same thickness as the spine until you get close to the cutting edge and then it's ground to the appropriate angle to form the edge; often about 25 degrees. This makes for a great field knife since the bevel is rather obvious, making field sharpening fairly easy. However this also makes for an edge that dulls more easily and can require more work to keep sharp. It's also a great shape for whittling since again the cutting edge is fairly obvious and easy to see. The other drawback is that if your spine is fairly heavy, it can be difficult to cut through some items as the back tends to get hung up once you get too deep.
Similar to the V-grind is the Flat Grind. With this one, the grind starts right at the spine and goes straight down to the cutting edge. This produces a knife with the potential for a much sharper edge than commonly found on a V-grind, but at the cost of removing a fair amount of metal from the blade resulting in a weaker, more delicate blade. It's biggest strength is that the single flat grind makes it another easily field sharpened knife. Just lay the side of the blade flat on your stone and you're good to go. This type of grind is most commonly seen on various chef's knives and other professional kitchen knives, though Spyderco and a few others do use a flat grind on several of their pocket knives.
The next grind is a Saber grind, also called a High Flat Grind. Somewhere between a V-grind and a Flat grind, a Saber grind starts it's angle closer to the spine but still leaves a fair amount of metal coming down flush from the spine resulting in a edge that's almost as sharp as a true flat grind but still retains the additional strength of the spine similar to that enjoyed by a V-grind. This tends to result in an excellent compromise between strength and sharpness and can be found in many survival knives and hunting knives.
One grind that is increasingly popular today is the Hollow grind or Razor grind as it's sometimes known. With this one a concave curve is ground into the blade from near the spine to the edge giving you a edge second to none for sharpness. It is this reason why this ground was used for straight razors back in the day, and it's still popular for hunting and skinning knives. The drawback here is that the sharper you make the edge, the less metal you have supporting it resulting in an edge that needs constant attention in the form of honing and sharpening.
Another one that is gaining in popularity among some in the business is the Convex grind. On this one the grind is also curved, but in the opposite direction from the hollow grind. This results in an cutting edge that is extremely durable and holds an edge quite well. The biggest drawback is that it requires speciality equipment to sharpen. Still, if you're willing to pay to have your knife professionally sharpened or to spend the money on the right sharpening equipment, this grind produces a survival knife that can cut and chop almost anything you throw at it.
Then there's the Chisel grind. Like it's namesake, a chisel grind only grinds away one side of the blade, leaving the opposing side straight and flush from spine to cutting edge. Although this grind also requires a lot of maintenance, making it something of a specialty blade; it's is fantastic at what it does both for the woodworker and the chef who is most likely to find this edge on his or her cleaver.
Finally there's the Complex, or Double grind. As it's name implies, this grind actually uses two grinds or bevels to produce the cutting edge. This is extremely popular with manufacturers since it allows them to use one grind in the initial forming of the blade and a second grind, which may or may not be a different type, to form the actually cutting edge. An excellent example can be seen in this picture of the main blade of a Christmas themed knife I sold this past winter. The main grind or bevel is stone washed as well as engraved and runs from just in front of the spine to the second grind, which is mirror polished making it much easier to see. By producing the edge this way, the manufacturer does not run as much risk of damaging the engraver or the employee running the engraver.
And that's it in a nut shell my friend. Well, actually there is one more grind, called the asymmetrical grind; but that's basically using one grind (say a flat grind) on one side of the blade and a different grind (say maybe a convex grind) on the other. Knives and cutting instruments with this style of grind are all specialty units of one type or another and unlikely to be found at your average knife shop. Still I should mention them just for completeness sake if for no other reason.
So there you have it. Every type of grind I know about distilled down to their basics for you. If we keep this up, you'll be a knife expert before school starts back up, and be able to amaze your family with the knives you buy them for Christmas. But in the mean time, this should have been published last night and I'm going to be late for work if I ramble on too much longer. So I'll just wish you all the best my friend, May the sky's always be sunny for you and the breeze ever cool. And until we meet again in this little corner of cyberspace I call mine, and remember; if it's worth doing, it's worth doing with attitude!