What is a hollow grind? And why it makes sharpening easier
Written by Mattias Höög · Last updated
Short answer
A hollow grind is created by grinding the bevel against a curved wheel, leaving a gently concave bevel. On a carving knife it is combined with a flat section at the edge ("flat over hollow"), so only two narrow rails touch the sharpening stone. The blade settles flat on the stone by itself, stops rocking, and touch-ups take seconds instead of minutes.
Flat grind vs hollow grind
Most standard factory carving knives come with a flat or Scandi grind, where the bevel slopes straight down to the cutting edge in one flat plane.
A hollow grind, by contrast, is created by grinding the bevel against a curved wheel, leaving a slightly concave curve in the middle of the bevel.
The secret: flat over hollow
While a pure hollow grind curves continuously from spine to edge, a high-performance carving knife uses a hybrid approach known as flat over hollow. When you lay a flat-over-hollow knife on a sharpening stone, only two narrow areas actually touch the stone surface: the front rail right at the cutting edge, and the rear rail along the back shoulder of the bevel.
- The front rail sits right at the cutting edge.
- The rear rail sits along the back shoulder of the bevel.
- Together they act like a pair of built-in guide rails on your sharpening stone.
Why it is great for carving knives
- It eliminates hand rocking and wobble: instead of balancing a flat blade at a guessed angle, the blade naturally clicks flat onto its two rails and stays planted, so you feel the correct angle instantly, without jigs or years of practice.
- Sharpening is dramatically quicker: the steel in the middle of the bevel has already been scooped away, so you only remove a microscopic amount of metal along the two narrow rails. Touch-ups are significantly faster and need far less effort.
- Minor edge damage is fast to fix: on a flat blade a nick means grinding back a thick wall of steel; on a hollow grind the metal at the contact points is much thinner, so nicks come out in a fraction of the time.
Does a hollow grind make the blade weak?
A common myth is that scooping out metal makes the cutting edge weak or brittle. Because the final sharpening forms flat contact rails right at the cutting apex, it restores full structural strength to the edge. You get a robust blade that handles tough hardwoods while keeping all the ease-of-sharpening benefits of the hollow grind.
Learn hollow grinding with Mattias
Mattias Höög, the maker behind Mattis Slöjd, runs a full course in hollow grinding a knife. It walks you through grinding the bevel on a wheel, establishing the two contact rails, and maintaining the edge on stones and strops step by step.
Join the free sharpening course in the Knife Sharpeners community →Frequently asked questions
- What is a hollow grind?
- A bevel ground on a curved wheel, so the middle of the bevel is slightly concave instead of flat.
- What does "flat over hollow" mean?
- A hybrid grind where the concave hollow makes up most of the bevel, but the final sharpening forms a flat rail right at the edge and another at the back shoulder. The two rails rest on the sharpening stone and hold the angle for you.
- Is a hollow grind weaker than a flat (Scandi) grind?
- No. The flat contact rails formed at the cutting apex restore full structural strength to the edge, so it stands up to tough hardwoods like any properly sharpened flat bevel.
- Why is a hollow grind easier to sharpen?
- Only the two narrow contact rails touch the stone, so almost no metal needs to be removed. Touch-ups take seconds and small nicks come out far faster than on a flat bevel.