Making
the Fingerboard -- 2
This is a vacuum jig I use to hold the fingerboard while I am cutting
the fret slots. The "tree" is simply a network
of shallow grooves which distribute the vacuum. The gray border
is the foam tape which contains the vacuum, and the white tube
is the vacuum supply. You can just see the metal pin at the end
which is used to index the fingerboard in the correct location.
This shows the fret cutter in operation. The jig which holds
the fingerboard has slots cut on the bottom which correspond to the fret
scale (I have one for each of the two scales I use: Martin
25.4" and Gibson 24.75.) There is a "finger"
in the sliding table of the machine which fits tightly in the slots and
thus indexes each slot individually. The table is one linear bronze
bearings and slides back and forth under the blade. The blade itself
is a screw slitting blade which can be bought from most machine shop supply
houses. They come in a wide variety of thickness. I
use a .023" which works well with the fret wire I use, and as it
has no set, it cuts a slot that is exactly .023". this machine
was built for me many years ago by a machinist in Wisconsin, and has worked
flawlessly for over twenty five years. I love it. I
opted for a single blade cutter since that gives me much more flexibility
in making boards with different scales -- all I have to do is make
a new jig.
Here are a few of the boards I cut for my current
batch of guitars. Total time from raw boards to profiled and slotted
boards for 16 boards was about 2 hours.
This photo illustrates a simple but very effective jig. It is designed to
drill the holes in the edge of the fingerboard for side dots. These
must be very accurately placed to look good. I started with a steel
bar about 1/8 x 1/2" and marked out a straight line exactly parallel
to the edge. Then, using my fingerboard for a gauge I marked out
the locations for the side dots, and drilled a 1/16" hole at each
location. I mounted the bar on a flat board which was in turn mounted
to a wide board. I drilled
through the board attached to the metal strip, and installed two toggle
clamps on the wide board to hold the fingerboard in place (a pre-set stop
ensures that the fingerboard is precisely located, and shims ensure that
a fingerboard of any thickness can be centered on the holes in the metal
strip.) It is then a simple matter to clamp in the fingerboard and drill
the holes. It takes perhaps 15 seconds per board.
the
current version of this tool was made for me by a machinist who is a friend.
Here is the fgbd with
holes drilled.
And again.
The next step is to carefully finish the top of the fingerboard.
Earlier I noted that I cut the arch on the fingerboard on a shaper.
Now I mount the fingerboard in a vacuum jig to hold it very firmly and
work it with sanding blocks having the same radius as my cutter (14").
( I get these from Stewart MacDonald) This removes any cutter
marks left from the shaper. I work the board down to a 600 grit
paper.
This is the vacuum jig
I use to hold the fingerboard while I am final sanding it.
One of the radiused sanding blocks
Here I am doing the
sanding with the shaped sanding block. For what its worth, I finish
my fingerboards to a 14" radius. (Martin uses a 16"
radius, and Gibson is closer to a 12" radius.)
After the sanding is done I run a triangle file very lightly
along each edge slot. This has two benefits. First, it removes
the sharp edge of the slot and seems to assist the fret to go in easier.
Second, when the guitar eventually needs refretting there is less likelihood
of chipping the fingerboard when the old fret is removed.
I use a fret press to install the frets. Here I have cut the
frets to rough length and started them in the slot on one end. I
will start all the frets before I begin the pressing step.
Another view of
the fret press.
Here I am using the press to install the frets. This works
very well and gives a very uniform fret job. It would be less effective
if I wanted to install the frets after the fingerboard was mounted on
the neck or after the neck was glued into the body. Each of these
methods has its benefits and disadvantages - truth be known I do it this
way largely because that is the way I started and simply have grown accustomed
to the method.
Another view.
Here is the completed fingerboard with the tools I use - a brass
hammer, an end nippers for cutting the fret wire, the triangle needle
file and a coil of fret wire. I prefer to buy the wire this way
because there is no need to pre curve the wire before installation - it
is already curved. We buy a lot of fret wire and this is the most
economical method. We buy most of our standard fret wire from the
Martin company and get it in about 5 tang widths, which is essential
for a repair shop.
The next step is to glue the fingerboard to the neck.
This
website and all of its content, text and images are copyright ©1997-2011
by Charles A. Hoffman. All rights reserved.
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