The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

108 Core Boatbuilding Techniques
Now remove excess stock to get close to the lines you
have drawn. <strong>The</strong>re are many ways to do this: you can
make a careful cut with a sharp handsaw, sawing as
close to the marks as your skill will allow, or you can
use a wide chisel and mallet, a large plane with a deepset
blade, or a power plane. When you have rough
machined the bevel close to its marks, use a sharp
block plane to finish it, watching the marked lines as
you proceed.
At this point, place the stock on a flat surface such as a
workbench with a block under the feather edge of the
bevel which can support the edge but will not interfere
with the hand planing. Continually check the bevel for
flatness in both directions so that when you plane the
bevel to its final marked lines, you leave a fine, feathered
edge at the very end of the stock. When you have
completed the scarf bevel, check to make sure that it is
flat in both the length and widths planed—we just set
the edge of the plane on the bevel surface for a quick
check. This ensures a totally flat surface, which will
mate properly with another scarf bevel to form a
dimensionally accurate and strong scarf joint.
<strong>The</strong> scarfing jig
To save time, you can easily build a jig on which to
mass produce accurate scarf bevels on various sizes of
straight lumber. Our basic scarfing jig design, shown in
Figure 12-1, operates on the same principle as a miter
box. A typical miter box is really only useful for cutting
45° bevels, but this jig can produce the angles of cuts
needed for 8-to-1 and 12-to-1 bevels.
<strong>The</strong> final dimensions of the jig are determined by the
stock to be beveled, but we always have made ours a
little larger so that we can bevel a reasonable variety of
stock sizes on one fixture. Construct the jig by bonding
two upright fences onto a flat base, making the fences
and base long enough to support the stock being cut.
Cut a mortise into the bottom of one of the fences of
the jig to receive a wedge, which will hold the stock
firmly against the opposite fence. <strong>The</strong>n lay out the
bevel angle accurately and mark it on the jig, being
extremely careful to make sure that the sawing line is
perpendicular to the jig floor so that you will produce
square bevels. Make the first saw cut into the jig, using
a back saw or a carefully controlled panel saw. This first
Fence
Wedge
Fence
Stock
Base
Figure 12-1 Basic scarfing jig.
Fence
cut is crucial to an accurate jig. Test its accuracy by
manufacturing several beveled joints and checking
them for squareness. Now you can use the jig to
manufacture scarf bevels by placing stock in the jig
and using a back saw or panel saw to make the desired
cuts. You may need to finish the bevels with a sharp
block plane.
You can also set up this scarfing jig on the table of a
radial arm saw. Clamp the jig to the table so that it is
angled slightly to the travel of the saw to produce the
exact bevel desired as you pull the saw blade through.
Clamp lumber in the jig and proceed to cut the bevel.
Although the set-up with the radial arm saw takes
longer, it vastly increases the speed at which you can
machine bevels. It is not unheard of to manufacture
over a hundred accurate bevels per hour when you
are well set up and organized.
<strong>The</strong> router method
Another method of making bevels is to use a router in
conjunction with a guide fixture. This has one advantage
over the scarf jig in that it has the capacity to cut bevels
in stock of a wider dimension range. <strong>The</strong> disadvantage
is that the basic fixture takes a little more time to
engineer and construct and is not so portable because
it must be aligned with a flat surface in order to be of
value. Usually this fixture is permanently attached at
the end of a long, flat surface, such as a workbench,