beats a knife in the bush. You use it to bleed your kudu, skin it,
cut biltong, trim riempies and clear away branches for your shooting
lane. In the bush you need a knife that is efficient - and it can
only be at peak performance when it is really sharp
Your knife will get dull with use, so you need to
sharpen it so we tried a whole bunch of sharpeners, many of them
junk or not just not made for Africa.
We quickly eliminated electrical sharpeners, the
drag-through type (which removes a small sliver of steel and various
other devices that can not create a double bevel.
Our criteria was a razor’s edge - functional,
consistent and easy to repair - in the African bush, far away
from electricity and paid sharpening services. We did not want a
super-fragile shaving edge - you are here to hunt, not to make a
advertisement for men’s cologne. We also wanted a system that you
can use at the Mopani fire at night while quietly chatting and
sipping your Cabernet Sauvignon, something that was easy to use,
reliable and did not weigh our daypacks down.
We eliminated all but 2: The Lanski Sharpening
System and the locally manufactured Warthog Classic II Sharpening
First, some basics
Several things - blade thickness, blade shape, edge
angle, edge thickness and edge smoothness will determine the cutting
ability of your favourite hunting knife.
Blade thickness has a great effect of slicing
ability. Because of the thickness of the blade, your hunting knife
will never slice like a the thin blade of a filet knife - no matter
what you do to the edge.
Blade shape is determined by the function. More
belly or curve is typical of a skinning knife and the straighter
edge of filet knives are designed for slicing.
We wanted to choose the correct to choose the
correct edge type for a hunting knife.
Here are the options:
The simplest and most widespread in factory knives.
The edge tapers from both sides of the blade. Sharp but sacrifices
durability. The sharp transition point induces extra drag.
Provides the most durable edge at a given angle and
has less drag compared to other edge grind types due to smooth
Instead of tapering in a straight line, the edge is
slightly curved outwards. The famous Japanese Samurai katana used
this type of the edge.
3. Asymmetrical Semi Convex
Combines durability of the convex edge and ease of
sharpening of the flat edge, until the edge gets real dull.
4. Asymmetrical Flat
The edge tapers on the straight line from both
sides, but the angles are uneven. Used for more durable edges but
sharpness is sacrificed.
5. Compound or Double Bevel
Cuts better than a flat edge at the same angle as
the secondary bevel, yet lasts longer than a flat edge if ground at
the same angle as the primary bevel.
Provides a strong, durable edge but sacrifices a
degree of sharpness.
The edge contours are concave, resulting in a very
sharp edge with low durability. Extra drag is induced due to the
shoulders and sharp transition points.
The edge is flat from one side, tapers on the
straight line from the other side of the blade. This is the sharpest
edge, found mainly on chisels in western world.
The Japanese use the chisel edge widely in their
8. Chisel with Back Bevel
This variation of the Chisel edge. Back side has a
micro bevel, usually at a very low angle of 3°-5°. Some sharpness is
sacrificed for increased edge durability.
9. Chisel with Urasuki
Urasuki is traditionally found on Japanese single
beveled knives. Back side of the blade is concave to reduce the drag
Serrations help with cutting by letting the edge
attack repeatedly from different angles with varying pressure.
Serrated edges are useful for cutting food and rope
– but for a hunting knife you need a plain edge.
The Best edge in the bush
In the bush you need:
The compound bevel is the only edge which provides
all that is required.
Factors that affect efficient cutting
The Warthog System
Edge angle is measured between the center of the
blade and the bevel or flat cut by the sharpening surface. Most
Western knives are double bevel.
Asian knives and woodworking tools are single bevel,
and the resulting smaller angle can make them aggressive cutters.
That is why sashimi knifes seem so sharp.
Any edge thickness under a few thousandths of an
inch may be considered sharp. Paper is about 2 to 3 thousands of an
inch thick - but it and will cut you if conditions are right.
Edge thickness naturally increases with wear.
Ideally, the cutting edge would come together to
make a perfect edge with zero edge thickness, but edge thickness is
limited by several factors.
First is malleability, or the tendency for steel to
move when it is pushed. The yield strength of steel is thousands of
pounds per square inch, but as the edge thickness approaches zero,
it takes only a fraction of an ounce to move it. The force of your
hand with a stone or steel can move enough steel to create or smooth
The second limit to edge thickness is edge
smoothness. You can’t have a 1/10,000-inch edge if you have
scratches 1/1000 inch deep. The grit of the cutting stone determines
scratch pattern or smoothness. Good edge smoothness requires careful
work with your finest stone
To be sure you are improving your sharpening; you
need an objective way to test the results. Tests evaluating
sharpness range from cutting silk to chopping trees. What you need
is a test method that is useful for you.
Most people test an edge by rubbing their thumb
lightly across the edge and feeling how the edge grabs as it tries
to cut into the thumb pad. To keep your thumb calibrated, test a
known sharp edge like a new razor blade periodically.
Shaving hair on your hand or arm is another common
sharpness test. Shaving sharpness can be achieved even on heavy
hunting knives or an axe. Razor sharpness is only possible with both
a polished edge and a small edge angle.
Although you will look as cool as Crocodile Dundee,
testing by shaving can be misleading if the blade has a burr or wire
edge. Steel naturally forms a burr - a thin bendable projection on
the edge - during the sharpening process. A blade with a burr will
shave but will not stand up to hard use. To test for a burr, slide
your fingertips lightly from the side of the blade over the edge.
You will feel the burr drag against your fingers. Test from both
sides, because burrs are usually bent over one way or the other.
The Lansky System
Another test for sharpness is to press the edge
lightly on your thumbnail at about a 30-degree angle. If it cuts
into your nail it is sharp and if it slips it is dull.
The sharper the blade, the smaller you can make the
angle before it slips. Try this with a new razor blade to see how a
really sharp blade feels. The down side of thumbnail testing is that
the little cuts in your nail get dirty and look bad until the nail
grows out. For this reason some people do this test using a plastic
pen or pencil.
As your sharpening improves you will be looking for
smaller and smaller burrs.
The glint along the cutting edge means a dull blade.
Many good sharpeners have learned to see a dull edge. Hold the blade
in front of you with the edge in line with a bright light. Move the
blade around a bit. A dull edge will reflect a glint as do nicks and
A sharp edge does not reflect glints.
The only tool available for edge testing is the Edge
Tester from Razor Edge Systems. The Edge Tester evaluates edges on a
100 point scale for sharpness and smoothness. The principle is
similar to the thumbnail test, but the Edge Tester has a special
material and shape for repeatable testing.
If you’re serious about sharp knives, get an Edge
The most effective test?
All these tests (apart from the Edge Tester) are
We use another way to test sharpness.
A better test
We measure the amount of force it takes to cut
through a loop of thread. Repeated tests of this type give data that
can be evaluated using statistical methods.
For each test a loop of thread is tied and suspended
from a small scale. The blade is placed inside the loop and pressure
is applied against the thread.
The maximum force before the thread is cut indicates
the sharpness of the blade, with smaller numbers reflecting a
Steeling and Stropping
Steeling is swiping the cutting edge against a steel
rod - also called a steel or a butcher’s steel – to realign the
How to do it
Hold the rod vertically and swipe the knife along
it, as if you are making a cut. They key is to try to match the
angle you are holding the knife at to the same angle as the edge
Using a magic marker will help. Cover the cutting
edge with the marker and make a swipe or two. Wherever the marker is
gone that’s where you are hitting the edge.
If you are doing everything right, then all you need
is 3-5 passes per side to realign the edge.
Stropping is a necessary and effective step after
Stropping serves the same purpose: aligning the
cutting edge by it on a piece leather. Stropping normally is done on
the plain leather, however coating the leather with an abrasive
compound such as diamond paste or chromium oxide powder will make a
Hard steel (above 62-63HRC) doesn’t respond well to
stropping on the plain leather. Borosilicate or ceramic rods are
effective on very hard steels.