UNDERSTANDING GRINDS AND THEIR BENEFITS
Discover different blade grinds and the advantages of each. By Jerrie Barber
It started at the beginning of time. Since a caveman cut himself on a piece of obsidian, man has been constantly refining the way he cuts things. From single-edge and double-edge arrowheads made of stone, to limber steel, to refined steels. From a ground edge to a mirror-polished razor’s edge. Blades for prying, for abuse and for elegance. Blades to baton through limbs and blades to clean your fingernails and open envelopes with. Sure, when talking about the anatomy of a knife, we could have talked about blade metals or shapes, etc.
The story could have gone on for days. In the following story, we’re going to focus on a few grinds (the shape of the cross-section of the blade) and discuss the advantages of each. We will discuss why some knives may be easy to sharpen or easy to dull and how the geometry of the blade plays a role in both. I will also briefly discuss makers because they are the epitome of that specific grind. Let's get started.
The flat grind is the most popular. This grind is most commonly achieved by going from the back, or the spine of the blade and symmetrically removing metal in a straight line toward the back of the primary bevel, just before the sharpened edge on either side of the spine. In the end, the effect is an isosceles triangle ground down to the cutting edge. (Scandinavian grinds and saber grinds also use flat grinds in that at some point, that isosceles triangle comes into play in the symmetry of the blade.) Commonly you would think of a chef’s knife or a butcher’s knife. In our world, the knife that comes to mind is nearly any knife made by Spyderco that incorporates the full flat grind into a myriad of products in their catalog.
The Saber grind most commonly will keep the width of the spine of the blade to about halfway down the distance of the blade toward the cutting edge. This is to give strength to the blade for tasks such as slashing and chopping. When thinking of the most classic saber grind knife, I often consider the KA-BAR Marine knife, though many makers incorporate a saber grind in their blade design.
The Scandinavian grind (Scandi grind) is similar in geometry to the saber grind, except that the width of the spine is carried out for almost three-fourths of the of the blade, until a flat grind is incorporated to the primary bevel. This grind makes an excellent field craft knife. Because the width of the spine continues for so much of the blade, when splitting wood or cutting hard material, it acts more like a splitting maul, keeping the material from the sharpened cutting edge, helping the blade stay sharp. A true Scandi-ground knife has no secondary bevel, which makes it different than the saber grind, and makes sharpening somewhat challenging.
Knives with flat grinds are relatively easy to maintain, even as they wear and age. Who hasn't seen that ancient pocketknife with the one blade almost sharpened to the spine? With that said, in the knife world, if it is easy to sharpen then it is easy to dull as well, so there is some consideration when choosing a flat-ground blade.
“CONVEX BLADES ARE EXTREMELY STRONG, ESPECIALLY BEHIND THE CUTTING EDGE, AND MAKE EXCELLENT HARD USE KNIFES, USEFUL FOR PRYING AND FOR FIELD CRAFT.”
One grind that continues to spark debate is the hollow grind. A hollow ground blade starting from the spine of the blade, starts to narrow and continues the removing of metal in a convex or inward grind to the cutting edge. Picture a straight razor and apply that to a knife blade. While there are several who use this grind, I most commonly think right away of Chris Reeve knives, who have mastered the hollow grind and continue to make improvements on this cutting technology.
While you may believe this is the most useless of the four grinds I will discuss, it is probably the most useful for everyday carry. While it is true that a hollow grind will chip easier during hard use, there are two things to consider. One, because of the narrowness of the blade at the cutting edge, you can sharpen a hollow ground knife on almost anything, such as the bottom of a ceramic coffee cup or the top edge of your car window, to bring that edge back to life. While I prefer a good sharpening system, the above-mentioned avenues for touch up are available.
Two, improvements in metallurgy, in my opinion, gives us better metal to work with and lessens the little dings we used to get from lesser quality metals.
A direct opposite of the hollow grind is the convex grind.
A convex grind comes from the spine and continues for a span as flat stock then slowly curves in a bow inward, toward the cutting edge. Other blade shapes come to mind, specifically the Scandi grind, however the Scandi grind comes to a point then makes a flat descent to the cutting edge. When I think of the convex grind, no folding knife comes to mind; however, what does come to mind is several of the blade designs that Bark River has in their EDC line. I own and often carry a Bark River Little Creek, which is an outstanding example of a convex grind. While it is harder to capture in photography than the other grinds, you can feel the outward roll in the contour of this grind in this specific blade shape.
Knives with a convex grind are not necessarily hard to sharpen but are harder to sharpen without a good sharpening system. Convex ground knives over time become more difficult to sharpen in the long term without having some professional touch ups made to the blade. Convex blades are extremely strong, especially behind the cutting edge, and make excellent hard use knifes, useful for prying and for field craft.
Lastly, and probably the most obscure and least understood, is the chisel grind. A chisel grind is a complete flat back side of the blade, in the front is a complete flat for about half the distance of the blade, then a drastic flat grind to the cutting edge. This is an obscure blade shape but is commonly being used by new makers, now more than ever. While it is obvious to me and many others, when thinking of this particular grind Emerson is the company that rises to the top of the list when utilizing this grind for a folding knife.
In considering the chisel grind, there are two major advantages that come to mind.
One, when sharpened correctly, a chisel ground knife possesses a devastating edge with the ability to do unspeakable damage to the target it is being used against.
Two, there is only one edge to be sharpened, and it is nearly impossible to make a mistake. Simply use your abrasive on the ground side. When you have reached your desired level of sharpness, remove the burr from the back side and the sharpening is complete. In the chisel grind, you also have a double use in one blade. Much like a wood worker chisels with the flat side up, you can curl wood or other material with ease, or turn the blade ground side up and remove a large amount material with equal effectiveness.
AT A GLANCE
While this is in no way a comprehensive look at all the grinds available in the knife world, they are the most common grinds you’ll come across, without getting into custom knives. There are plenty more grinds to learn about, and each has its own particular use.
“IN THE KNIFE WORLD IF IT IS EASY TO SHARPEN THEN IT IS EASY TO DULL AS WELL, SO THERE IS SOME CONSIDERATION WHEN CHOOSING A FLAT GROUND BLADE.”
No matter how ornate the grinds on a blade, if the grind begins at point A and ends in a straight line at point B, it is a flat grind.
Chris Reeve has made an excellent product with his line of folding knives. These are the best example of a hollow grind. Notice how there is almost a sweeping effect getting deeper and deeper all the way to the cutting edge.
Full flat back, with a flat grind starting at the midway point of the face of the knife with a steeper bevel at the cutting edge. Emerson knives are the epitome of the chisel grind knife blade. This knife is an excellent user as well as a devastating tactical defense blade. While this is a little tricky to see in a photograph, notice how the cutting edge of the knife blade moves away from the straight edge, rounding to the cutting edge. This Bark River Little Creek is an example of a convex grind.