this information is given by Chad Ward, a knife sharpening expert.
This information will also be explained to you in person upon
completion of your knives.
The ability of a knife to hold an
edge is affected by several factors. Many are properties of the
steel, others are job-specific.
Wear resistance – the
ability to resist abrasion – comes primarily from the amount, type
and distribution of carbides in the steel.
resistance to low-impulse deformation. In other words, bending.
Strength is directly related to the hardness of the steel.
is resistance to high-impulse deformation – impacts, chipping and
As a general rule, strength and toughness are
inversely related. A hard, unbendable steel can be brittle. It will
not withstand chopping through bone as well as a tough, slightly
softer steel. A tough steel might roll its edge if it encounters
significant lateral stress or is forced through very hard materials –
stresses that a strong steel would easily resist. The most extreme
examples of both would be the extremely hard, yet shatter-prone
ceramic knives from Kyocera compared to very tough, soft stainless
Edge holding is a function of wear
resistance, strength, toughness and the tasks the knife is used for.
Toughness is required to resist chipping when you are cutting through
materials where you might encounter bone or other hard bits and
pieces. Strength is required to resist rolling and impaction if, for
example, someone in your kitchen (despite repeated warnings) uses a
glass cutting board. Wear resistance becomes important for edge
holding when you’re cutting through abrasive materials.
the way your knife holds an edge depends on the steel and what you
use the knife for.
The most common culprits that put wear
resistance, strength and toughness to the test are:
Duh. As a knife blade encounters abrasive materials, the edge wears
away. Unless you cut only soft foods, your edge will always wear
somewhat, though the most wear in the kitchen will come from
sharpening your knives. Significant wear could take years.
and rolling. As pressure is put on the edge of the blade (and
remember, the edge’s job is to concentrate tremendous amounts of
pressure), the edge can indent, impact or roll over to one side or
the other. The harder the steel, the less likely it will be to indent
or roll. This is actually fairly common in the kitchen, which is why
you need to steel frequently (more on this below).
The edge can chip or crack under impact, especially when encountering
hard materials like bone. Micro-chipping can be an important factor
in edge degradation, although kitchen knives are fairly
Corrosion. The wet, acidic environment of the
kitchen can give knives a real beating. Micro-rusting and the attack
of acidic foods can lead to edge loss at the very apex of the edge in
Technique. As chef Thomas Haslinger points
out, “Having sharpened my own knives and other chefs’ knives, I
can say that an often overlooked factor in cutting edge performance
is how each individual holds and uses his knives. A person that
‘feels’ the cut will always have a knife that outperforms an
individual who just cuts and slams the edge into the cutting
Steeling your Knife
regularly is the most critical maintenance you can perform on your
knife. Whenever you use your knife, especially soft kitchen knives,
the edge can turn out a bit. Turn the knife with the edge pointing to
the ceiling under strong light. You shouldn’t be able to see it.
The edge itself should be invisible. If, however, you see glints of
light, those are spots where the edge has rolled. The edge is still
reasonably sharp, it’s just not pointing straight down anymore. The
steel realigns the edge of the knife, forcing the rolled spots back
into line, making it useable again.
will get into the various types of steels in just a moment, but be
aware that the grooved steels that come with knife sets do in
fact remove metal. A grooved steel acts as a file when used with a
heavy hand, knocking microscopic chips out of your edge. At the very
least, it is much coarser than the fine abrasive you used to achieve
your edge. Steeling heavily with a grooved steel is taking several
steps backward. A grooved steel should be used with caution and a
very light touch.
The standard image we all have of steeling a
knife involves a chef with his knife in one hand and steel in the
other, blade flashing and ringing. If you’re particularly adept at
this type of swordsmanship, have at it. It impresses the tourists.
more effective method is to stand the steel straight up and down with
the handle up and the tip resting on a folded towel to keep it from
slipping. Why? Geometry.
Place the knife edge against the
steel with the blade perpendicular to the steel – 90 degrees,
right? Rotate your wrist so that you reduce the angle by half – 45
degrees. Reduce that by half – 22.5 degrees, and you are exactly
where you need to be to steel your knife (if you have a 20 degree
edge). You generally want to steel at a very slightly steeper angle
than the edge bevel itself.
can also use the Paper Airplane Trick to make a guide to prop
against your steel so you know you are hitting the proper
When you’re steeling, lock your wrist and stroke the
knife from heel to tip by unhinging at the shoulder – it’s your
pivot point – and slowly dropping your forearm. The key is to
maintain a consistent angle all the way through the stroke. By
locking your wrist and elbow, you will keep your angle stable from
top to bottom. Go slowly and follow all the way through the
tip. You don’t have to press very hard to realign the edge.
Steeling requires barely more pressure than the weight of the knife
Alternate from side to side, keeping the same
alignment and angle on both sides. It really only takes four or five
strokes per side to get your knife ready for more work.
should you steel? Every time you use your knife. Oddly enough,
steeling before you use the knife is much more effective than
steeling afterward. A steeled edge can be very sharp, but it is not
as durable as a freshly honed edge. If you don’t use a steeled edge
right away it can actually relax back into its blunted state. The
same is true of a blunted edge. If you really degrade the edge of
your knife in a heavy cutting session, let it sit overnight before
sharpening. It will be in much better shape than it was the day
You should also steel before sharpening so any rolled
or impacted edges are pushed back into alignment. That way you don’t
cut off the rolled edge and lose more metal than you really need to.
You also can steel after sharpening to add a final bit of polish
(especially on a medium to medium fine edge) and tooth alignment. A
steel actually “smears” the edge, teasing out a little more
thinness. You’ll have a keener edge, but it will be weaker than the
freshly sharpened edge.