The hollow grind is a very common grind for knife blades. Hollow-ground blades offer excellent cutting properties and are more flexible than blades with a different type of grind. They are mainly used to for hunting and outdoor knives as well as kitchen knives. We also hollow-grind our straight razors.
Hollow-ground blades are ground on both sides. This blade is known for its concave grind (curved inward) that starts a third or even halfway down the blade height and continues down to the edge in a slight curve. Looking at a cross-section of a hollow-ground blade, the blade starts out straight and ends in a sharp taper towards the edge. The bevel, meaning the ground section of the blade, is much thinner in hollow-ground blades than in convex or flat-ground blades.
The hollow grind is achieved by holding the blade to the grinding wheel at a right angle, which "hollows" the blade. Since this method results in a very sharp taper of the blade towards the edge, hollow-ground blades are very sharp but not particularly sturdy. How much the blade can withstand depends on the size of the hollow and the radius of the grinding wheel. If the radius is large, the taper will begin higher on the blade, which makes the knife less sturdy. On the other hand, a grinding wheel with a smaller radius creates a blade with a fairly short taper, which will make the knife more robust.
Hollow grind knives are best suited for thin, soft materials. They should not be used for firm materials with a larger diameter. Traditionally, hollow grind blades were used for straight razors and scissors. Today, you can find this blade type mainly in hunting and outdoor knives, as well as kitchen knives.