VERITAS Mk.II, Руководство пользователя

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32
Veritas
®
Mk.II Power Sharpening System
If that is not possible, initial fl attening can be done on
a belt sander. Only when the face is very close to fl at
should you start working it with stones.
Most chisels made today are ground reasonably well.
Two types that you should immediately be suspicious of
are chisels that have been hand ground (several German
styles) and chisels that have been polished. Hand-ground
chisels are almost never fl at, square or straight. Polished
chisels almost invariably have the sides rounded and the
face dubbed next to the bevel. The rounded sides (above)
prevent you from getting a fl at, full-width cut; the dubbed
face (below), if uncorrected, would mean that you would
constantly have to tilt the chisel up to get it to cut. You
would then have poor control of the tool.
To fi x the dubbed tip, you usually have to grind about
1
/
16
in. off the bevel. Lapping the chisel face will show
when you have removed enough material. To true
rounded sides, you can use a belt sander or dress them
back on a stone. It is best to do such dressing on the edge
of the stone, because you can quickly wear a groove in
the stone when repeatedly rubbing a narrow edge in the
same spot.
For lapping most chisels, you can start with an 800x or
1200x stone and then go directly to a 6000x or 8000x
stone. This is one time you want to be absolutely sure
that your stones are fl at, because it is a fair amount of
work to lap a chisel and you do not want to have to do
it more than once.
It is not necessary to get the entire face of the chisel
fl at. Just as you can tolerate some hollowness fore to
aft, you can tolerate some hollowness from side to side.
If you have a chisel that is slightly hollow from side
to side, you can stop lapping it as soon as you get the
face to approximately the same confi guration as most
Japanese chisels, which are ground hollow on the face
(see the bottom chisel in the photo above). You do not
have to be concerned that the edge will eventually reach
the hollow portion. In the normal sharpening process
the hollowness will slowly be eliminated as you remove
a small amount of metal each time you sharpen.
Shaping the Edge
There are two basic activities to shaping the edge of a
chisel: setting the basic bevel angle and then honing it.
The guiding principles you use here are that the bevel
angle should be the lowest possible one consistent
with edge retention in intended use, and that you want
to spend the minimum amount of time resharpening.
Under each chisel type discussed later in this chapter,
there will be recommended basic bevel angles, as well
as exceptions to the general process that I am about
to describe.
Hollow grinding: For at least the past twenty years,
various cabinetmakers have recommended using a hand
or power grinder to put a hollow bevel on a chisel so
that it can be rapidly honed. The basic principle is that
you clamp the chisel in a simple jig that can be slid
back and forth on the grinder tool rest to grind a regular
hollow from one side of the blade to the other. When
you then hone the chisel, only the very front and the
very back of the bevel will ride on the stone. This makes
it possible to hone blades without using a honing guide,
since it minimizes the tendency of the blade to rock
during honing.
Most Japanese chisels (above) are ground hollow on the
face, whereas Western chisels (top) are ground flat.
Chisel Defects
Chisel
Stone
Chisel with hollow face
Chisel with bellied face