There are several ways to grind the
edge of a knife, such as a convex grind, a hollow
or concave grind and a straight or V grind. The convex
grind is best in application where heavy materials
like wood need to be cut with a great deal of force.
The cutting edge is supported by a thick edge of steel.
The hollow grind is the opposite of the convex. In
this grind the side of the knife is hollowed out along
the edge forming a concave shape. This grind is best
suited for cutting softer materials like food, where
the blade cuts deeply. As the convex edge begins to
wear, it becomes more difficult to sharpen. The hollow
grind, however, stays at relatively the same thickness
through many sharpening. The straight grind or V wedge
is a compromise between the convex and hollow grinds.
For a hollow grind, two concave scoops make the edge.
If done right, this leaves the edge extremely thin
and sharp, for exceptionally good slicing ability.
This type of edge works best when high-performance
cutting is needed. It is less suitable for chopping
tasks, because the same thinness that gives the edge
such great slicing performance also makes this format
more prone to chipping or rolling during high-impact
activities. That makes this edge especially good for
chores that emphasize cutting over impact uses.
This grind has the sides of the blade arcing down
in a convex curve to the edge. The edge on this format
is often very sharp, because the convex curves run
all the way to the edge without a secondary bevel.
It is also a strong edge format, because the thin
edge thickens quickly enough to have plenty of metal
behind it. The main drawback of this format is that
it is extraordinarily difficult to re-sharpen. Knifemakers
today tend to use a slack-belt grinder to apply this
edge format. You can sharpen the edge in a normal
beveled manner, but then you'll end up with just a
regular beveled edge that thickens quickly, a format
that will be strong but won't be the best cutting
The flat grind is a format that combines most of the
cutting ability of the hollow grind, with most of
the strength of a saber grind. Flat bevels run all
the way from spine to the edge bevels. This can leave
the edge thin for high-performance. However, the edge
thickens linearly as it moves up, so it ends up stronger
than a hollow grind. This grind is also expensive
to make, as the maker is required to remove a lot
of metal. The combination of cutting ability and strength
makes this a great all-around grind. From kitchen
knives (which require thin, hi-performance cutting
edges) to cooks (which require strong, shearing edges),
and all uses in between, the flat grind is often an
The saber grind has flat edge bevels that normally
start around the middle of the blade, and run to the
edge bevel. The kabar and many other military knives
show this grind. The emphasis on this grind is strength,
as the edge is often left thick, and thickens dramatically
and quickly past the edge. Cutting ability is sacrificed
to some extent for durability. This is a format you'll
often see on knives that will take prying, digging,
and chopping abuse, such as the "sharpened prybar"
type knives. This grind does show up for other uses
as well, such as utility use.
The chisel grind is ground on one side only. One side
of the blade has an edge bevel on it; the other side
is completely flat. Because of this, the edge on a
chisel-ground knife is usually extremely thin and
sharp and cuts very well. On the downside, the asymmetrical
grind causes the knife to veer off course during cutting
chores; it also thickens dramatically. This format
has become popular on tactical knives, often coupled
with a clip-point Americanized-tanto blade.
Scandinavian knives, such as the puukko, often sport
a grind that looks like a saber grind. However, there
are no secondary edge bevels, which leaves the edge
extremely thin and incredibly sharp. Due to the sharpness
of the edge, these knives will often outcut just about
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