BENT KNIVES AND THEIR USES
It is hard to really track down where bent knives started out. Many
carvers have found them to be very useful.
You are able to get into
places where chisels can't reach. If you read on you will see what I mean.
WHY A BENT KNIFE:
Carving Illustrated wrote of world famous carver Chris Pye: Although
Chris Pye is a traditional carver and not known as a user of knives as
such, he does see carving gouges as essentially "glamorous, curved
knives with the handle moved around to the side". The hook knives proved
perfect for the particular work in hand and elsewhere. It was also
obvious that other carvers, particularly knife carvers, would find them
a very useful part of their kit of tools as well.
The blades of these knives are mounted close to the surface of the back
of the handle that makes it easier to work close to the surface of the
wood.
A benefit of the double edge bent knife is: when you are carving and the
grain in the wood starts to travel in another direction all you have to
do is use the other side of the knife to bring the cut in the opposite
direction. All you are doing is cutting in the opposite direction
instead of having to turn the whole carving around.
To understand how and where the certain curved knives are used I will
try and explain the other benefits. I am sure when you try them you find
the areas where these knives will benefit you as a carver. Bent knives
can be used in many different areas of carving. The knives can be used
in concave areas and for the relief cuts in the background of a relief
carving. The blades on these knives can be used to the very tip making
it very easy to cut right into a stop cut. A Preferred Edge sharpened
bent knife can cut across the grain on red cedar with out tiring the
wood. It also helps if you use a slicing action for this cut.
BLADE STEEL:
The blade is made from a high-grade tool steel. The steel code is L6.
L6 was engineered for woodcutting saw blades and related tools. The
Rockwell hardness on these bent blades after they have been heat treated
by Preferred Edge are RC 57+. At this hardness these tools are easy to
sharpen and stay sharp for a long time.
BLADE BEVELS:
Bent knives can have a bevel on the inside or the backside. There are
benefits to both bevels. Each one will have to be sharpened
differently. See sharpening instructions on www.preferrededge.ca .
INSIDE BEVEL:
With the bevel on the inside the dig can have a more aggressive dig.
This blade wants to dig into the wood because the bevel is on the
inside. When this blade wants to dig too much all you have to do is use
the opposite side of the blade and cut in the opposite direction.
BACKSIDE BEVEL:
In most cases when the bevel is on the back or bottom side you have
better control of the digging. The cut with this blade wants to stay
toward the top of the wood. With this tool there is less chatter when
you are cutting in a tighter radius.
HOW TO BEST HOLD THE BENT KNIFE:
There are three main versions of the bent knife. Slow Curve, High Curve
and Hook. They will be explained a little more in depth as we go along.
Each version of these knives can be held the same way when you start
using them. To hold these knives lay the back of the handle in the palm
of your hand that you will be using to carve. The tip of the blade should
be pointed upward as shown in DIAGRAM A. Place the thumb toward the top
of the handle and the little finger should be wrapped around the cord
above the blade. See DIAGRAM B
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Diagram A |
Diagram B |
There are different ways to use the bent knives. I have had carving
lessons, observed carvers and used carving tools myself. I have found
that to get the best use of these knives, hold it in your hand at a 90
degree angle, the way it is mentioned above.
To start out put the bottom
of the blade flat on the wood that you will be carving on. The handle
of the knife at this point should be angled back about 15 degrees and
blade laying flat on the heel of the blade. Use the heel of the blade to
carve with, then angle the handle toward you 5 to 10 degree to start
with. Make sure that your elbow is tucked into your side and then put
some pressure on the knife and start to drag it toward you.
Through the
cut keep your wrist straight and when you want to cut out pull the blade
of the knife up toward you. IF the blade feels like it is digging in too
much, stop and make a cut from the opposite way, using the opposite side
of the blade.
The angle of the knife will determine the depth of the cut meaning the
more the knife is angle off of the vertical 90 degree the further it
will dig in. You should not have the angle of the vertical 90 degrees
any more then 20 degrees. In other words the knife handle should not be
any more then 70 degree toward you, see Diagram C
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Diagram C |
When using all three of these knives remember to keep your elbow to your side and your wrist straight and pull or push depending on the direction of cut, the knife blade should be up when you want to cut out.
The knife has a cutting edge on both sides so you will want to use both
cutting edges. You will be able to do a push or pull action with this
knife. This will save you the effort of turning your carving around when
the wood grain changes direction.
This theory can be used in all three different bent knives. It
usually takes some practice so don't get discouraged. To practice get a
piece of clear quarter sawn also known as edge grain wood and try the
cuts pitching the handle at different degrees. Don't stop the practice
until you are comfortable with the cuts you are getting.
As was mentioned there are three basic shapes in the bent knife
category. There is a slow or slight curve, a high carve and a hook.
SLOW OR SLIGHT CURVE KNIFE:
Some carvers also call this the plaining or planer knife. As it
suggests this knife has a very slight curve toward the end of the
blade. This knife can be used for the shallow concaved areas and also for
plaining and leveling on relief carving areas. For example, sometimes an
area had to be leveled to draw reference lines. The blade is sharpened
out to the tip so you will have no problem cleaning out an area up
against your stop cut. With the pointy part of the knife you will be
able to get into tight areas and make effective cuts. Again you can
travel in either direction for your cut.
HIGH CURVED KNIFE:
This knife is a higher curve then the previous knife. The blade will
have a large radius in it. Depending on the size of the blade the blade
will bend up to almost 90 degree. It is sharpened to the tip of the
blade. The wide curve or radius makes it excellent for cleaning out
knife marks left behind by other knives like the hook knife. This knife
is also very valuable in deep relief carving. I use this knife to level
and clean the flat areas of a relief carving. You are able to get into
tight angled areas. Cutting across the grain is usually no problem with
this knife. Try and use the slicing method with this practice.
HOOK KNIFE:
Easily recognized by the hook at the end of the blade. This knife is
very useful in roughing out bowels and spoons and also concaved areas of
a relief carving. I have had sculptors, in Switzerland, use this knife
for skirted areas and areas like under the arm or in a crotch area where
there is a tight radius. In these areas this knife is used like a scorp.
This knife is also great for using across the grain. I would also like to
remind you that the angle of the knife would determine the depth of the
cut. Also remember to hold your wrist straight and pull the blade up
toward you when you want to cut out.
For further useful information on using bent knives please read the article in Woodworking in America.
Using Bent Knives - Woodworking in America
If you need more help please call Mike at 1-888-811-5551.
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