|
|
|
The work table behind the radial arm saw's outer fence must be relieved to
accomodate the saw spindle. A piece of 3/4" x 4' x 8'
plywood is temporarily fastened to the saw's apron. A guide strip is clamped
under the piece to be scarfed (in this case a piece of 1/4" x 31"x 96"
plywood). The strip runs along the leading edge of the 3/4" plywood
apron and keeps the stock perpendicular to the saw's fence.
|
If your stock's length is less than the width of your apron, butt a
square piece of plywood to the right of the stock and push it
against the saw's fence. This will square up the stock as you
feed it into the saw. Shown above is a narrower apron with a
guide strip clamped to the stock.
|
The saw is raised several inches, rotated to a horizontal position
and tilted to a 5 degree bevel. A pair of spring steel hold downs
are used to keep the stock firmly planted on the saw's apron.
|
Since a blade guard can't be used on this setup, don't get too close
to the exposed blade and watch your fingers ! Note that the leading
hold down is positioned so as to prevent kickback as the stock exits
the blade.
|
The maximum scarf length is only limited by the length of your saw's runoff apron.
|
The finished product.
|
Scarf width is 2-1/2". A thin-rim 72 tooth carbide finishing
blade was used to get a clean cut. The scarf's leading edge is
paper thin and can be quite ragged. It can be squared up and
trimmed with a sharp utility knife running against a large framer's square.
|
An 8' section was bolted to the router table to make up a 16' long table.
|
A strip of plastic film was placed on the table at each seam before
laying out the scarfed panels. Pictured are two pieces
31" x 96" being scarfed to a piece 31" x 26" which will
make up the side plankng.
|
The seams were adjusted and witness marks were scribed
on the panels to facilitate re-assembly.
|
The joints being epoxied.
|
Line up the witness marks, clamp the panels to keep them from moving,
cover the joint with a strip of plastic film and a piece of plywood
about a foot wide and apply weights. Excessive weight will squeeze
too much epoxy from the joint and lead to an unsound joint.
|
Check to make sure the panels are aligned properly.
|
Once the epoxy has cured, the joint is ready for finishing.
|
This 18' long side planking panel was built up from three pieces of 1/4" plywood.
|
Closeup of a scarfed joint using 1/4" marine plywood.
|
Sample epoxy-coated joint.
|
The epoxy should be left to cure for several days before subjecting
the panel to severe bending stresses.
|
|
