I thought I'd try to put up a little
tutorial on knife sharpening, as it comes up all the time on the Hoodlums...
In particular, I wanted to chat up the convex edge, as it is not as well
known as other blade geometries...
There are several techniques, each of them
effective, and which you choose depends on the particular use you have for
the knife. Instructions can be found all over the 'net, so I'll not
address all of them here.
Back when I was a kid growing up in West
Virginia, everyone carried a pocket knife, and used a carborundum stone to
sharpen them. There were no sharpening "systems" back then.
Today, most folks are aware that there are bench stones, yet most cannot use
one correctly. So they gravitate to one of the sharpening systems that
hold the blade at a pre-selected angle to the stone. Lansky is one
that has been around for a long time, and does a really good job on most
knives... I have used one for many years. Recently, I
changed to using a Pro-Edge, when I need a "V" shaped secondary
bevel.
Before going further, go here and read this
article on edges...
If that link disappears, you can Google
"convex edge" and find it in a couple of places...
Now that you have read that, I have only a
few comments re: the convex edge. I have changed over to using it on
most all my knives. If an edge gets too thick, I will use the Pro-Edge
to knock the shoulders down, and create a thin "V" edge, then
convex that. It might make a purist weep, but hell, I'm the one
using it...
The vast majority of my knives are now
convexed, and most of them are used in the field. As a wilderness
knife, I expect to cut cordage, whittle things like a spoon or a trigger for
a trap, create a fishing pole, or maybe shave wood for a fire. I find
that the convex edge is easier to use than a "V" edge, in
particular when shaving bark off of a piece of willow. The
"V" edge will dig in, where the convex edge will glide down
the length of stick, taking off the amount I want. There really
is a noticeable difference.
You can flop a piece of mouse pad down on
your workbench, and hold a piece of sandpaper on it with your off hand.
That works just fine. However, if you want to take a kit into the
field with you, you might consider what is known as a Hoodoo Hone. It
is named after the inventor, Dr. Terry Trier, who is known around the
various blade and knife forums as Hoodoo...
Glue a piece of mouse pad on a block of
wood, and make a couple of slits into the ends... You can use some
wooden wedges or even use guitar pics to hold the paper firmly in
place.
Here is another good idea: mouse pad
for sandpaper on one side, and a leather strop charged with green polishing
compound on the other. Hone and pics by Dannyboy...
Dannyboy tells me that the hone is 4"
long by 1 1/2" wide. The cedar block is only 3/4" thick.
It weighs all of 3 ounces. As you can see, it does not take a huge hone
to be effective.
Various grits of paper will give you lots of
options. After you have achieved the proper edge, stropping it on a
leather strip charged with polishing compound will maintain it pretty well...
Sometimes if it gets a little too dull, you might use a piece of old,
worn 1500 grit paper to touch up the edge. If it gets really
buggered up, you might have to go all the way back to 220 grit, and reshape it
all over again.
In any event, draw the blade away from the
edge, sanding the entire edge until there is a burr (wire edge) along the
whole blade. Then turn it over, and do the other side until you
have a wire edge again. Go to the next finer grit, and do again...
The only major thing I would say is that I
can see two possible mistakes a beginner might make. I've made them
both...
1. Holding too high of an angle between
the back of the knife, and the sandpaper. As you can see from the
graphics, the soft backing allows the sandpaper to roll around the edge. The
higher you hold the spine of the knife, the more that rounds off the edge.
You can get a really dull edge in a really short time doing that, lemme
tell ya!
;-)
2. Failing to hold a constant angle.
Mostly, this consists of allowing the spine to come up, as you draw the knife
backwards over the paper. You can see that graphically represented in
the convex edge article, where the technique for using a bench stone is shown.
The effects are the same as #1. You really have to watch that you hold
it at the same angle throughout the stroke.
It takes some practice to find the right
angle, it is lower than you think, especially if you are experienced with
using a sharpening stone... Along with this, please understand that you
will scratch the sides of your knife. If you have a nicely polished
custom knife, I would think twice before attempting this.
The strop is used after the sandpaper, to
remove the wire edge that will have developed. You can also screw up and round
off the edge with the leather strop, by being too aggressive with the angle,
as well... Polishing compound gives the leather a bite, and can really
polish the edge up nicely. Most of my woods bumming knives I leave with
a very toothy, coarse edge. I just knock off the wire edge, and call it
good.
Polished edges are great for shaving, but the coarser edges are better for
working field knives, IMHO.
The harder the steel, the harder it will be
to use any technique for sharpening. Once, I reshaped the edge on a TOPS
knife. I used a Lansky system, with an extra coarse diamond stone, and a
magnifying glass to follow the progress. It took a week to grind a new
edge on it. Some of the new wonder steels are tough to work with, and
the more abrasion resistant it is, the harder it is to re-sharpen.
For one of those blades, I would use the
Lansky or Pro-Edge system, and call it good.
I want to thank Hoodoo and Dannyboy for their generous permission to use their pics. They really show the hone well.
Hope this helps in some way...
Bill
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Copyright © 2005 by William Hay.