From: rhaar@albert.cs.gmr.com (Bob Haar)
Newsgroups: rec.backcountry
Subject: Re: Sharpening knives
Date: 3 Oct 92 15:49:50 GMT
Reply-To: rhaar@albert.cs.gmr.com
Organization: G.M. Research and Envirnmental Staff

In article 718042649@blackjack, mhart@blackjack.dt.navy.mil (Michael Hart) writes:
|>
|>Hi!  I just started perusing this group, so pardon if this is a
|>frequently covered subject.
|>
|>I'm trying to locate information on sharpening knives.  I'm basically
|>more interested in the home/kitchen variety, but I suppose
|>most information is more or less applicable to those and the
|>more outdoorsy-type most rec.backcountry readers would be 
|>interested in.
|>
|>I'd like to get info on techniques for sharpening, materials 
|>required, tips, hints, gotchas, whatever.
|>

You might also try rec.woodworking for general sharpening advice.

What you need to do depends on where you start. If the edge has
significant nicks or if you need to reconstruct the shape, then
you will need to start with files or a grinder. If you are using 
an electric grinder, go slow and work in short intervals to avoid
overheating. It is quite easy to destroy a good blade by overheating,
thus removing the temper.

If all you need to do is to resharpen a blade that has been
dulled through normal use, then you will need to use just some
sharpening stones, progressing through a series from coarse
to finer grain. There are all kinds of different stones, natural
and synthetic. I use water stones in my workshop, but I would
not recommend them for someone getting started. Buy a set of
oil stones (2 or three stones is enough to get stated). 

I would avoid the diamond dust on metal lattice style. These
can be useful for quick touchup ( and for light sharpening
of carbide tips) but are not as good for general use. Likewise,
the diamond-dust tools that look like fine sandpaper glue on a
plastic handle are good in there place, but are not large enough
for sharpening moderate to large blades.

As you use the stones, hold the blade at a fixed angle to the
stone and move it as if you were slicing a thin layer off
the stone, at the same time sweeping the length of the blade edge.
The angle at which you hold the blade depends on many factors
but is generally 20 to 30 degrees. Higher angles provides a blunter
edge that is good for rougher use. The precise angle is not as
important as consistency.

The single hardest part of the technique to master (IMHO) is
keeping a consistent angle. For this reason, the sharpening
set sold by Lansky is very good. I won't try to describe it use
because it is much easier to understand if you are looking at one.
But the set consists of set of sharpening stones with handles and
a device that clamps onto the blade and holds the stones at a 
constant angle while you sharpen. Using this, it is straighforward
and quick to get a good edge. the only problem is that the
set up is too smal for use with really large kitchen knives,

Beyond this, you can use polishing wheels on a grinder or a
leather strop to razor sharp edges. Also, if you are serious
about sharpening, there are water cooled, electrically powered
sharpening tools available.

---
	Robert Haar               InterNet : rhaar@gmr.com 
	Computer Science Dept., G.M. Research and Environmental Staff
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.