A Guide to Knife Grinds

Different brands of knives use different kinds of grind.

Flat or V Grinds

Very common on Japanese knives, simply both sides of the knife extend down towards the edge of the blade at a common angle. Flat grinds can produce very sharp edges, and are wonderful at making very thin slices. More common than true flat grinds are double bevel grinds, which have an initial shallower grind before being finished with a secondary bevel.

As the edge finishes at a microscopic point, flat edges will dull more quickly than other edges.

Flat edges are produce by sharpening against a flat surface such as a whetstone or horizontally spinning stone.

Convex Grinds

Convex grinds are the most difficult to produce owing to the outward bowing of these edges, it is not produced by traditional grindstones or whetstones. They are not commonly seen in knives.

Convex grinds are considered to be the best edges to put on knives, as when you cut pressure is pushed away from the angle edge. You feel this in the cut which always feels smooth as there are no kinks or edges that you feel when cutting through food. Secondly as pressure is reduced on the cutting edge, convex grinds can stay sharp and feel as though they stay sharp for longer. Global are the most famous brand of knives make use of convex grinds.

The downside to a convex grind is that they are very hard to reproduce on a blade than anyone other than a very experience sharpener. Convex grinds can be reproduced on a slack belt sharpener, but these machines are quite difficult to use, noisy and messy and not so suitable for home or kitchen use. However if you have access to a specialist knife belt sharpener, convex grinds produce wonderfully satisfying edges on knives.

Hollow Grind

Hollow grinds feature concave surfaces which finish in a very thin extremely sharp point. Concave grinds are produced by the profile of the sharpening system, usually some sort of wheel. As the grinds finishes in a very sharp point, concave grinds can be the sharpest but least durable edges. Useful for blades that need a very high initial sharpness but don’t need to hold an edge for so long, such as razors.

Which grind is best?

This is a big debate, but usually comes down to the blade geometry and what the knife is being used for. Most high end Japanese knives we see come with a double bevel and certainly this is simpler to produce and easier by the user to maintain.