Kenneth Michael Guitars est.1978
KMG "Success Kit"
|Preparing the top and the rim for gluing
In this step we are going to fine tune the fit of the top to the rim. Specifically, the
intersection of the “X” brace where it passes through the rim. To stabilize the top during
the marking process, the mold needs to be prepared to accept rubber band clamps.
Mark the centerline on a few of the mold slats, pre-drill and install screws. The top or
back can now be clamped in place using standard #64 rubber bands tied together.
(Editorial) The notion that a guitar builder needs some sort of there special, very
expensive rubber band is ludicrous.
Two #18 gage brads are used as
locating pins at the neck block end of
the top. Drill two holes approximately
one inch either side of the centerline
along the perimeter drawing on the
inside of the top. Note these holes are
tangent to, (touching) not through the
Gently butt the locating pins against
the rim, align the centers of the top
and the mold. Secure the top in place
with several rubber bands to prevent
Using a very sharp pencil, mark the top braces where they meet the rim kerfing, mark
the rim kerfing where the braces cross.
Also mark the flat top brace where it
intersects the neck block.
The rubber bands can now be
removed. Trim the flat brace using a
utility knife and razor saw, take care
not to damage the top.
Since the ends of the braces (top and Back) actually protrude through the rim its
important that the depth of the notches is limited by the width of the binding. Note that
in photo below, the binding must cover the thickness of the top or back plus the
depth of the brace notch.
Normally bindings are about .20” or just under ¼”. Since the top is thinned to about .11”
we have MAXIMUM of .09” leeway for the notch depth. To be on the safe side the
notches should be cut a little shallow --- So happens that the standard Popsicle (craft)
stick is .07” thick so it makes a very handy depth and thickness gage. Don’t let the
numbers confuse the issue of hiding the notch, be sure to understand the goal. Also
make practice cuts before actually cutting in to the rim.
The two upper bout ends of the “X” brace and the ends of the shoulder braces need to
be thinned to the thickness of our gage. Shave material until the ends are slightly
thinner than the gage. Note the intersection line of the kerfing --- level the ends slightly
beyond the marks toward the inside.
The bass bar and side brace ends are clear of the rim kerfing, if there is interference at
the kerfing line shave/sand the ends so they do not touch the kerfing. The lower bout
ends of the “X” braces were shaped previously. Note that these ends float in the
notches we are going to cut in the rim, this allows the top to flex a little more, there is no
attempt made to have a rigid joint at this location. Many builders keep the ends clear of
the rim for the same reason. The inlet strategy aides in locating the top for the gluing
Use a straight edge to connect the
intersection marks, use a very sharp
pencil to draw lines where the braces
will intersect the rim and kerfing.
|Saw a piece off a craft stick to use as a depth-marking gage.
|Use the gage to draw a line on the rim outside and inside.
Use a utility knife to score slightly above the depth mark using several light passes
“LEAVE THE LINE”. Score at all locations outside and inside.
Using a razor saw make several cuts down to the score line. Use the same procedure at
Use a small chisel to clear the notches, work from the score marks inside and out. Use
a piece of craft stick to check the depth. The bottoms of the notches should be flat
Using the rubber bands secure the top to the rim. The braces should lock into the
notches, check to make sure the centerlines are PERFECTLY aligned, and check the
clearance at the neck block. Most importantly be certain that the notches are deep
enough so that the top seats on the rim all the way around.
Perform a practice clamping run using the special top and back caul. It’s not necessary
to put screws in every location at this time. Do not use any rubber bands with the clamp
since that could make dents in the top. Once satisfied, remove the caul apply glue to all
the mating surfaces, position the top, position the caul. Secure the caul in several
places around the perimeter. A drill motor is OK to use to get the screws started but
final tightening must be done by hand. Check from the inside to make sure the top is in
the right location and seated correctly. Insert the rest for the screws tighten the caul
alternating from side to side to prevent applying uneven pressure.
|Here's a great DIY tool idea for creating uniform notches
Rim notch tool