VERITAS Mk.II, Руководство пользователя

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43
General Sharpening Procedures
In practice, whether or not you get chatter with a low-
angle block plane depends almost entirely on the fi t of
the blade to the bed and how well you can tension your
blade with the lever cap. A well-tuned standard block
plane will chatter less on end grain than a low-angle
plane with a blade just as sharp but that has not otherwise
been tuned. In my view, once the blade is clamped in
position properly with a lever cap of the right length,
bed angles become a secondary consideration; cutting
angles remain signifi cant.
Given the curious state of block-plane production today,
I would look fi rst for a block plane that can be tensioned
properly (e.g., a Record #09
1
/
2
), get an extra blade, and
then have one blade sharpened for regular block-plane
use and the other blade sharpened for low-angle use.
Low-Angle Block Planes
Having undermined the argument for having a low-angle
block plane, let’s take a look at them anyway. You want the
lowest possible cutting angle when you are working end
grain. One aspect of cutting end grain is that the lighter
the cut you make, the lower the relief angle required. This
is fairly straightforward because the lighter cut causes less
fi ber distortion and therefore less springback.
So for fi ne trimming work on end grain (where you are
not going to be taking heavy cuts), I would recommend
that you put a 20° bevel on the blade and a 5° back bevel
(see the drawing on the previous page). This will give
you a 32° cutting angle. For working softwoods only,
you can change this even more. You can put a 15° bevel
on the blade and a 5° back bevel (see the drawing on the
previous page). But if you do this and inadvertently use
the plane on end-grain oak, you can expect to put some
marvelous serrations in your blade.
It is diffi cult to be defi nitive about many of these bevel
angles. Some people never skew a block plane in use;
other people always skew it. If you normally use a block
plane in a skewed position, you can get away with lower
bevel angles. If you are always working clear pine, you
can get away with very low bevel angles. Only you
know which wood you will be working and how you
will be working it. Experience will tell you what you
can and cannot do. All I can do here is provide you with
a rough road map.
In all of the block-plane drawings I have shown fairly
long back bevels. This was done only to make the
illustrations clearer. The back bevels should be very
short, only enough to give you the edge strength that is
required. In general, this means that a back bevel from
1
/
64
in. to
1
/
32
in. is ample. If you make the back bevels
too long, they start to interfere with the fi t of the blade
in the plane.
By now you should also have realized that there is a
strong argument for low-angle block planes. Not only
can you get the total cutting angle as low as 27° (which
is approaching the cutting angle of a chisel), but a block
plane is far easier to use in a skewed position than is a
chisel. If you then skew a block plane with a 27° cutting
angle, you can drop the effective cutting angle further
– to 20° at 45° of skew, and 14° at 60° of skew.
Whether or not you do any or all of the things suggested
here is almost incidental to my purpose. What is
particularly important is that you become comfortable
with the principles involved so that you can tune your
planes and shape their blades to suit your requirements
and your practices.
KNIVES
In woodworking, we are basically concerned only with
knives that cut wood. But this is a fairly narrow view
of the world. Over a lifetime, unless we just happen
to be carvers, we will all probably spend more time
using kitchen knives than woodworking knives. For this
reason, I’m going to talk about kitchen knives fi rst.
Actually, there is a second reason. No non-woodworker
is going to take a sharpening book seriously if it does
not have basic instructions on sharpening kitchen
knives. So this next section anticipates the question,
“Are you telling me that you bought a book on
sharpening and it doesn’t even tell you how to sharpen
a butcher knife decently?”
Finally, since edge-design considerations are so similar
for kitchen knives, belt knives and woodworking knives,
this digression into kitchen knives only reinforces the
need to adjust edge shape to intended use.
Sharpening Kitchen Knives
Kitchen knives are very easy to sharpen, which is
fortunate because most of them are left rattling around
in drawers or abused in a variety of ways that dulls
them very quickly. However, most kitchen-knife users
seem to be satisfi ed with the condition of the knife as
long as the cutting edge is keener than the back of the
knife. The tolerance for dull knives is amazingly high
in most kitchens.
The practical test of sharpness for a kitchen knife is
whether or not it will slice soft vegetables, meat or
bread. In all three uses, you do not want a knife with
a classically sharp edge such as I have described for
chisels and plane blades; you want a slightly serrated
edge, a sort of combination between a knife and a saw.