The bolster is the band that joins the blade to the handle.
Photo courtesy MOTHER EARTH NEWS editors
STAMPED KNIVES: Most less-expensive knives
are stamped from sheet steel and are lighter and thinner
than forged knives. Stamping can produce a decent blade,
but without the heaviness of a bolster larger stamped
knives may feel flimsy and unstable when used to cut
hard-surfaced foods such as watermelon.
FORGED KNIVES: Forged blades are made by
heating crude steel to more than 2,000°F and shaping it
with a mold and a hammer. The blade is then ground down,
tempered, sharpened and finished off. Forging is a
labor-intensive process, which is reflected in the cost of
BOLSTER: A sure sign of a forged knife is
a bolster — a thick collar of metal between the blade and
the handle. Manufacturers claim that the bolster adds
weight and balance to the knife, but it also keeps the
user's hand away from the blade, which makes the knife
TANG: In a full-tang knife, the blade
metal extends to the end of the handle. According to
manufacturers who produce full-tang knives, this gives the
knife more balance. The full tang is visible on wood handle
knives; on synthetic handles, full tang would mean that the
blade extends at least 60% of the way through the handle.
ROCKWELL HARDNESS SCALE: This is a
progressive measurement in degrees used to rate the steel's
hardness: from 52 for soft steel to 60 for high-carbon
CARBON STEEL: This is the oldest type of
steel used for knives and is hardened at 53 degrees
Rockwell. Carbon steel is easy to sharpen, but these knives
will rust and stain.
STAINLESS STEEL: Stainless steel knives,
first popular in the 1920s, resist rust and staining. The
blade is 61 degrees Rockwell, which means that it's too
hard to be sharpened on a steel and can only be sharpened
HIGH-CARBON STAINLESS STEEL: Most
manufacturers now combine the positive characteristics of
both of the above; high carbon makes the knives easier to
sharpen while the stainless steel keeps them from getting
stained and corroded. Every manufacturer has its own metal
recipe with some containing molybdenum and vanadium steel.
The specific combination determines how hard a blade is,
how difficult it is to sharpen, and how long it will hold
an edge. If a knife's Rockwell hardness is in the mid-50s,
it should be easy to sharpen but still maintain a sharp
MOLYBDENUM/VANADIUM: Molybdenum is added
to the steel mix to counteract the brittleness that's in
hard steels, and vanadium contributes a unique, microscopic
grain that makes it possible to grind a very sharp edge.