Untitled - Wood Tools

ATo cuf o scorf
ioinf, the router
is mounted to o
sled thot rides
on o shop-built
iig with bpered
sides. Use o &,o"
l/2" skoight bit
or spirol bit to
cut the wide,
beveled foces
of fte ioint.
SCARFJOINTS
Occasionally, it would be nice to have a board "stretcher."
The fascia and skirt boards on the porch, for example,
are over 20 feet long.We couldnt buy boards that long,
so we did the next best thing - we used a scarfjoint
to make one long board from two shorter ones.
Strong & Simple - Compared to many joins, a scarf
joint is quite a bit simpler.The basic idea is to take two fullthickness
boards and cut a bevel in the face of each one
to form a thin "feather" of material on the end.When put
together, these beveled faces create such a large glue surface
that the result is an extremely strongjoint.
Build,Then Cut - To make a scarfjoint, you'll need
to build a simple jig (Box on page 5|.This jig allows you
to cut the beveled faces in the boards with a handheld
router and 2 l/2" 5g6ight bit.
The jig shown here is set up to create a scarfjoint
with an 8:1 ratio. In other words, the board will have 8"
ofglue suface for every 1" ofboard thickness.
Adjust the Cutting Depth - After mounting the
router to the sled, the first step is to adjust the depth of
cut.To do this, place the router directly over the end of
the base of the jig.Then, set the bit depth so it just grazes
the edge of the base (Fig 1a).
Even though the bit is set at maximum depth, I
wouldnt recommend cutting the bevel in one pass.You'd
have to "hog" offtoo much material, which would put
a lot of stress on the bit. Instead, the idea is to make a series
ofprogressively deeper passes to produce a thin "feather"
of material on the end (Figs. l-j below).
Make the First Cut - fb accomplish this, set the
workpiece a few inches back from the end of the jig,
and clamp it firmly in place. Make sure it's butted against
FIRSI Clomp
wo_rkpiece obout 3"
FIRSt Reposition
workpiece obout
holfwoy toword
end of iig 2
shollow bevel on
foce of workpiece
SECOND: Cut o
deeper bevel
on second poss
Align workpiece
flush with end of
iig, then moke
o finol poss
A After odiusting the depth of cut
(Fig. Ia), clomp the workpiece
in the iig. Then moke o series of
posses io rout o shollow bevel.
A Tc increose the size of the bevel,
reposition the workpiece closer to
the end of the iig ond moke o
second series of posses.
A Now olign the boord with the
end of the iig ond moke the finol
posses. This produces o "feother"
of moteriol ot the beveled end.
50
woRKBENCH tr JUNE 2004