Stewart MacDonald 5297, Assembly Instruction Manual

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The two long X-braces (T-1 on the blueprint), the tall front
shoulder brace (T-5), and the tone-bars (T-2) are radiused .
The flat shoulder brace and the four small braces (T-3) are
not radiused .
With the soundboard face down on your workboard, place
these two X-braces on the penciled lines and mark where
they cross . With a razor saw, notch the radiused T-1 braces
so they interlock . Using the rigid workboard, dry-clamp the
ends in place, flat to the soundboard (pictured) . Clamp
the center of the “X” down, using one or two long cam
clamps . The combination of the curved braces and the rigid
workboard will produce the proper soundboard arch (a 28-
foot radius) when the clamps are removed .
As shown in the pattern, the ends of the T-2 tone-bars, the
four small T-3 braces, and the maple bridge plate tuck under
the X-braces . File these notches in the X-braces at a 45° angle
(pictured) . Using a sharp chisel, carefully shape a matching
angle on one end of these braces where they tuck under .
Reclamp the X-braces onto the soundboard and workboard .
Check the fit of the tone bars in the notches . Disassemble,
apply Titebond to the braces and tone bars, reclamp, and
let the glue dry overnight . This work can be done in stages,
depending upon the number of available clamps . Use
two flat clamping cauls for each pair of tone bars, with the
soundboard resting on your workboard to keep it flat at this
stage (pictured) . Cut the three flat soundhole reinforce-
ment strips (T-4) to length and glue them into position on
the soundboard .
Transfer the outline of the bridge plate from the blueprint
to the flat maple bridge plate stock . Saw out the plate and
true its edges against a piece of sandpaper taped to a flat
work surface . Don’t drill the bridge pin holes yet; this will be
done later . File a 45° bevel at each end of the bridge plate
and check for proper fit in the X-brace notches . File off each
pointed end of the bridge plate so that it can slide forward
as it tucks under the X-braces . Prepare a wooden clamping
caul to fit snugly over the installed bridge plate between
the X-braces, and glue the plate onto the soundboard
with Titebond or hide glue . The lower clamp jaws should
contact the back of your workboard to protect the spruce
soundboard .
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