Knife Blade Grinds: Flat, Hollow, Convex, & Chisel

A blade's grind determines how it cuts. Two knives made from the same steel, with the same hardness and the same blade length, will perform differently if their grinds are different. One slices through cardboard with no resistance. The other binds halfway through. The steel is identical. The geometry is not.

Grind refers to the cross-sectional shape of the blade from spine to edge. It controls how much metal sits behind the cutting edge, how the blade moves through material, and how the edge behaves under stress. Every grind is a tradeoff between cutting efficiency, edge durability, and maintenance difficulty. None is universally best. Each fits a specific set of tasks.

What a Blade Grind Actually Is

When a knifemaker shapes a blade, they remove metal from the blank to create the cutting edge. The pattern of that removal defines the grind. A blade that tapers in a straight line from spine to edge has a flat grind. A blade with concave surfaces curving inward has a hollow grind. A blade with a convex outward curve has a convex grind. A blade ground on only one side has a chisel grind.

The grind starts at a specific point on the blade. If the taper begins at the spine and runs the full width of the blade, it is a full grind. If the taper begins partway down the blade, leaving a flat section near the spine, it is a partial or saber grind. Where the grind begins affects blade thickness, rigidity, and cutting behavior.

This is not a cosmetic detail. It is the single most consequential design decision in a blade. Research on edge geometry has shown that grind profile affects cutting performance more than steel type or hardness rating. A mediocre steel with excellent geometry will outcut a premium steel with poor geometry in most practical tasks.

Flat Grind

A flat grind tapers the blade in a straight line from some point on the blade down to the cutting edge. The cross-section forms a V shape, or a truncated V if the grind starts below the spine.

A full flat grind begins the taper at the spine and runs it all the way to the edge. This produces the thinnest possible blade geometry for a given stock thickness. The blade moves through material with minimal drag because there is less metal behind the edge to create friction. Full flat grinds excel at slicing tasks. Cardboard, rope, food, packaging, and thin materials part easily.

A saber grind, sometimes called a partial flat grind, begins the taper lower on the blade. The upper portion remains at full stock thickness. This adds rigidity. The blade is stiffer and resists lateral flex better than a full flat grind. The tradeoff is more metal behind the edge, which increases drag during cutting.

Flat grinds are the most common grind on modern EDC knives. They balance cutting ability, durability, and ease of maintenance. Sharpening a flat grind is straightforward because the bevel surface is, as the name states, flat. It sits evenly against a sharpening stone. URBAN EDC carries a wide selection of flat-ground folders because this grind suits daily carry tasks better than any other single option for most people.

Hollow Grind

A hollow grind removes metal in a concave arc from both sides of the blade. The resulting cross-section curves inward, creating a very thin edge with minimal material behind it.

This geometry produces the sharpest possible edge at a given angle. The concave walls reduce contact area between the blade and the material being cut. Food releases from the blade surface because the hollow section pulls away from the cut material. Slicing is effortless. Hollow grinds dominate hunting knives, skinning knives, and straight razors for this reason.

The thinness that makes hollow grinds exceptional slicers also makes them fragile. There is very little steel supporting the edge. Lateral stress, hard impacts, and prying motions can chip or roll the edge. Cutting through dense material like thick rope or hardwood puts stress on the thin section and can damage the geometry.

Sharpening a hollow grind requires attention to the concave profile. A flat stone works on the edge bevel itself, but reprofiling the hollow section requires curved or slack-belt systems. For routine touch-ups, a flat stone or strop is sufficient. For full reprofiling, the process is more involved than a flat grind.

Hollow grinds appear less frequently on EDC knives because daily carry tasks often include hard materials like cardboard, plastic, and zip ties that stress thin edges. For users whose primary tasks are light slicing, a hollow grind performs exceptionally well.

Convex Grind

A convex grind curves the blade surface outward in a rounded arc from spine to edge. The cross-section is the inverse of a hollow grind. Where hollow curves in, convex curves out.

This geometry puts the maximum amount of steel behind the cutting edge. The curved surface distributes force across a larger area during cuts. The edge is stronger and more resistant to chipping, rolling, and deformation than any other grind type. Convex grinds tolerate hard use, including chopping, batoning, and cutting into dense or abrasive materials.

The tradeoff is cutting efficiency. A convex grind does not slice as cleanly as a flat or hollow grind because the outward curve creates more contact area between the blade and the material. The blade pushes material apart rather than parting it. For thin materials like paper or food, a convex grind feels noticeably less refined than a flat or hollow ground blade.

Sharpening a convex grind is the most difficult of the 4 primary grind types. A flat stone does not match the curved profile. The standard method uses a belt sander with a flexible backing, or a leather strop loaded with abrasive compound. Freehand sharpening on a stone is possible with practice but requires a specific rocking motion that takes time to learn.

Convex grinds are most common on fixed-blade outdoor knives, axes, and heavy-use tools. They appear on some EDC folders, particularly models designed for hard-use environments. For users who need edge strength above all else, the convex grind is the correct choice.

Chisel Grind

A chisel grind removes metal from only one side of the blade. The opposite side remains flat at full stock thickness. The cross-section looks like a right triangle rather than a V.

This asymmetric design produces an extremely thin edge on the ground side. At a given included angle, a chisel grind is thinner than a symmetrical grind because all the material removal happens on one face. The result is a very sharp edge that cuts aggressively on the ground side.

The asymmetry introduces a steering effect. When cutting, the blade tends to curve toward the flat side because the ground side offers less resistance. Straight cuts require compensation. This makes chisel grinds less suited to tasks requiring precision on a flat surface. Japanese kitchen knives use single-bevel grinds (a refined version of the chisel concept) and address the steering through specific cutting techniques.

Sharpening a chisel grind is simple in principle. Only one face requires work. Lay the flat side against a stone to remove the burr, and sharpen the beveled side normally. The process is faster than maintaining a symmetrical grind because half the blade requires no attention.

Chisel grinds appear on some tactical and utility knives. They are less common on general-purpose EDC knives because the steering behavior complicates everyday cutting tasks. For specialized applications, particularly in scenarios where aggressive cutting ability matters more than cut accuracy, chisel grinds perform well.

Compound and Scandi Grinds

Two additional grinds deserve mention because they appear on knives that EDC carriers encounter.

A compound grind, also called a double bevel, adds a secondary bevel at the edge of a primary grind. A flat-ground blade with a small secondary V bevel at the cutting edge is a compound grind. The primary grind provides the overall blade shape and rigidity. The secondary bevel creates the actual cutting edge. This allows makers to optimize the blade body for one property (strength, thinness) and the edge for another (sharpness, durability). Most production knives use a compound grind of some type.

A Scandi grind is a single flat bevel that extends from the edge upward without a secondary bevel. The entire bevel surface contacts the sharpening stone, making it one of the easiest grinds to maintain in the field. Scandi grinds are standard on Scandinavian outdoor knives and bushcraft tools. They excel at wood carving and controlled cutting tasks. They are uncommon on folding knives because the bevel geometry requires a specific blade stock thickness to work properly.

Grind Comparison for EDC Tasks

The table below compares the 4 primary grinds across the factors that matter most for daily carry.

For most EDC users cutting packages, cordage, tape, and food, a flat grind covers the widest range of tasks with the fewest compromises. URBAN EDC's catalog leans toward flat-ground folders for this reason. The grind serves the broadest number of daily carry situations without penalizing the user in any single category.

How Grind Interacts with Steel and Thickness

Grind does not operate in isolation. It interacts with blade steel and stock thickness to determine final performance.

• A thin blade with a flat grind and a soft steel (56 HRC) produces a knife that slices well but dulls quickly and flexes under pressure. The same thin blade with a flat grind and a hard steel (61 HRC) slices well and holds its edge longer, but may chip if twisted in a hard material.

• A thick blade with a hollow grind creates a contradiction. The hollow removes material from the lower portion, but the thick spine means there is still substantial steel above the hollow section. The blade may slice well near the edge but bind in deeper cuts because the upper body is too thick to part the material. Hollow grinds work best on thinner stock.

• Convex grinds pair naturally with thicker stock because the geometry already assumes substantial material behind the edge. A thick-stock convex blade is a tool built for power. A thin-stock convex blade loses most of the convex advantage because there is not enough material to create the characteristic outward curve.

Steel hardness interacts with grind angle. Hard steels (61+ HRC) paired with thin grind angles (below 15 degrees per side) risk chipping because the hard, thin edge cannot absorb impact. The same hard steel paired with a thicker grind angle (20+ degrees per side) holds up better because there is more material supporting the edge.

Knowing these interactions prevents mismatched expectations. A knife with the wrong grind for its steel and thickness will underperform regardless of brand, price, or reputation.

Choosing the Right Grind for Your Carry

Selection starts with your primary cutting tasks. If you cut soft to medium materials daily, flat grind handles everything. If you need maximum sharpness for light tasks and rarely encounter hard materials, hollow grind delivers. If you abuse your knife on hard materials or work in rough environments, convex grind absorbs the punishment. If you prefer aggressive cutting ability and can compensate for steering, chisel grind works.

Most people do not know their primary tasks when they buy their first EDC knife. The safe starting point is a flat grind in S35VN or 14C28N steel at 2.8 to 3.5mm stock thickness. This combination performs well across the widest range of tasks and forgives mistakes in both use and maintenance. URBAN EDC recommends this profile as a starting point for new carriers, and their staff can help match grind type to specific use patterns.

After carrying a flat-ground knife for a few months, you will have data. You will know what you cut, how often, and where the blade's geometry helped or limited you. That information drives the next purchase with precision that no guide can replace.