Grinding of knife blades

Blade Grinding and Blade Geometry

By applying different ways of grinding, various blade geometries can be produced:

Hollow grind

The cheapest way of grinding a blade. The blanked steel is just ground in the lower area. Typical way of grinding for very low end knives, but also for serrated edges.

PROS

Inexpensive

CONS

Thick blade above grinding area = high cutting resistance

A lot of cutting drag in area of concave edge

Thin and fragile blade on cutting edge

Graphic drawing showing geometry of a hollow grind knife blade in a cross section

Flat grind

The blade is ground flat on both sides to a thin edge.

PROS

Thin blade and potentially good sharpness

CONS

Thin and fragile edge

Contact of food along the entire blade = sticking and drag; more power needed for cutting

Graphic drawing showing geometry of a flat grind knife blade in a cross section

Convex grind

The blade is ground on both sides with a convex geometry. Common way of grinding German style knives.

PROS

Food contact only on small area of blade = less sticking and drag

CONS

Thicker blade in area close to edge = less sharpness

Graphic drawing showing geometry of a convex grind knife blade in a cross section

Graphic drawing showing geometry of a single bevel hollow grind knife blade in a cross section

Graphic drawing showing geometry of a Japanese grind flat convex combination thin grind knife blade in a cross section

Single bevel flat grind

Adding a flat bevel on one side of the blade. Common way of grinding for scissors, but not knives. Also found in cheaper look-alikes of traditional Japanese knives.

PROS

Very inexpensive way of blade grinding

CONS

Blade only works for either left- or right-handed people, not for both

Straight cuts are difficult

Single bevel hollow grind

Hollow-grinding of blade on one side, and adding a bevel from the other side. Way of grinding of traditional Japanese single bevel edge knives.

PROS

Very thin edge and hence very high sharpness

Generally good stability of blade

CONS

Blade only works for either left- or right-handed people, not for both

Straight cuts are difficult (which is intended for a very specific use)

Thin and hence fragile and sensitive edge

Combination grind

Almost flat grind on the upper part of the blade and convexing only in the lower 1/3 of the blade. Way of grinding of Japanese double bevel edge knives.

PROS

Generally thin blade, with added stability in edge area

Best compromise between sharpness and blade/edge stability

Less sticking/drag

CONS

More expensive, since more grinding steps