After the
slotless fingerboard is absolutely flat, I string up the
classical guitar, and leave it tuned for a day. After
that time, the neck should have the proper "relief",
meaning that the top of the fingerboard should be very
slightly concave or dipped, with the dip being centered
between where the 5th and 6th frets would be. This dip
should be between 1/64" and 1/32" deep, with
the greater depth on the bass side. This dip, or
concavity, begins at the nut, and should taper out to
flat around, or slightly beyond the 12th fret. This
relief is necessary because greater string clearance is
needed closest to the nut, because a longer string
vibrates over a wider distance. In other words, the
fingerboard should "fall away" from the string
more precipitously nearer the nut, and gradually less so
as the string is shortened in the higher fingerboard
positions. If the proper relief isn't present, remove the
strings and sand very carefully, using the blocks either
lengthwise (parallel) or edgewise (perpendicular) to the
fingerboard as necessary. All final sanding should be
done with paper no coarser than 220 to 280.
Now mark out the slots, by
first drawing a center line down the middle of the board.
Then draw parallel lines to this center line as close to
both edges of the board as possible. Then, with the
fretting stick, mark off the fret positions with a fine
pen or pencil. Finally, using a plastic or metal square
aligned up against either of the two parallel lines,
scribe the fret position marks.
Using the rubber-bottomed
fretting block with its 90 degree edge, I make my
starting cuts with the fret saw. A still finer toothed
and narrower saw than the fret saw might be used to make
the initial starting cuts in the fingerboard easier.
After approximately 1/32" deep starting cuts have
been made at all the fret positions using the .030" fret
saw, clamp two 1/8" strips of hardwood on both sides
of the fret saw with 2 smallest size c-clamps. Allow just
enough of the teeth and blade to protrude, so that the
saw would cut a slot the exact depth of the fret tang.
Place a protective piece of sheet aluminum on the guitar
top, with masking tape on the bottom of the metal, so
that the aluminum won't discolor an unfinished top. It is
also best to saw the slots twice, from both directions,to
make an extra clean slot. Finally, don't forget to always
experiment with scrap wood to test tolerances. (If you're
fretting a rosewood board you should use a .029" saw.)
Uncoil the fretwire and cut it
into 1 foot lengths. (I always use hard fretwire for
longer playing life, even though hard wire is more
difficult to work with.) I then carefully straighten
these foot sections as much as possible, using smooth
jawed pliers if needed. Finally, I cut the frets about 1/2"
longer than each fret slot, and I arrange them in order
on a work table. Before I begin hammering in the frets, I
very gently pass over the top of each fret slot with a
fine, triangular file. I do this in order to taper the
sharp edges at the entry point of each slot. This not
only permits easier entrance for the frets, but also
prevents chipping of the board, if the frets need to be
pulled out for any reason. I then vacuum out the slots
and begin.
I use liquid hide glue of
medium-thin consistency. (Don't use hot glue or other
glues.) Using a glue injector, I run glue inside 2 or 3
consectutive slots at a time. I quickly work this glue
into each slot with an extra-fine spatula, and I wipe off
any excess glue. I then place a fret over a slot and
hammer lightly at each end of the fret until the fret is
partially seated. I then tap across the fret wire with
the hammer, concentrating the taps on the ends of the
frets, and beginning with light taps and ending in
heavier taps as the fret becomes better seated. When the
frets are well seated, tap the protruding fret ends down
a very little bit, so that only the slightest bend is
visible when sighting along the fret. Wipe off the glue
ooze and continue, etc.
When all the frets are done, a
damp cotton cloth, or piece of towel will remove all glue
residue off the fingerboard. It is unnecessary, but
permissable to clamp a straight piece of wood to the
fingerboard to hold down all of the frets as the glue
dries. When dry, clip off the overhanging fret ends and
file the sharp edges smooth by running a fine flat file
along the edge of the board. The ends of the frets should
also be rounded off, and a small, very fine square or
rectangular file used to slightly round off the edge or
side of each fret at their ends. This will remove any
remaining sharpness at the fret ends that could irritate
a player's hand. Done properly, the frets will not need
filing on the crowns, except if they are considered too
high, and if flatter, lower frets are desired. (Sometimes,
frets are imperfectly made at the factory, and will need
filing for that reason.)
Lowering of the fret crowns is
done with a straight, flat, wide file, ideally, about 8"
long. Filing, in parallel strokes to the neck, must be
done in such a way that the neck relief is not disturbed.
On the other hand, if the relief is incorrect, now is the
time to make a slight correction.
If the crowns have been lowered,
they should be rounded off, since a square-topped fret
will not play cleanly or absolutely true. Roundig off, is
either done with individual fine files (where the
fingerboard should be taped off to prevent file mars), or,
more easily, special fret rounding files can be used.
When using the fret files, clean off metal chips, and
file mostly in one direction, in order to minimize
marring the frets.
When filing is completed,
polish the frets with fine silicon carbide paper, i.e.,
280, 320, 400 and 600 grades respectively. Finally,
polish the frets with 000 and 0000 steel wools. When done,
vacuum off all dust and steel wool fragments, and clean
off the fingerboard with a cotton swab and lacquer
thinner. Before stringing and playing the guitar,
lubricate the fingerboard with a 50/50 mixture of
turpentine and linseed oil, wiping off the excess.
Comments: if the fret slots are
too tight (narrow) for the fret tangs, the frets will
have a cumulative "wedging" effect on the
fingerboard, and force the neck backward, cancelling out
the neck relief. If the slots are too wide, the frets won't
seat properly, and the slots will compress when the
guitar is strung up, producing a "kerf" effect,
resulting in excessive neck relief.
The fretting methods just
mentioned, can be used when replacing fingerboards on
classical or on steel-string guitars with non-adjustable
necks, or when building such instruments. However, when
refretting such guitars, approximate relief adjustments
must be determined in advance, before the old frets are
pulled out. The degree of flexion in a non-adjustable
neck (before the old frets are removed), determines how
flat or relieved the fingerboard should be after the
frets are removed. If in doubt, always true a neck fiat,
and file some of the relief into the frets later, if
absolutely needed, which shouldn't be too often.
In the case of adjustable steel
string or electric necks, tighten the adjusting nut
several turns before truing the fingerboard straight. In
this manner, the truss rod can be loosened to allow for
adjustments in both directions. Additionally, this
prevents an internally loose or sloppy neck, which could
happen if the rod required complete loosening for proper
action after the guitar had been strung up. Such a neck
might rattle, and "sustain" could be reduced.
Additional notes: curved
fingerboards, to be arched properly, should be thought of
as being a "slice" off a tapered cone, with the
cone's bass being toward the guitar body. In other words,
the curvature of the arch at the top of the fingerboard
decreases the higher one goes up the neck away from the
nut. This also means, that a straight edge run parallel
to each string, and placed where each string would
naturally lie, must be flush and level along the entire
length of the fingerboard. When "fretting" an
arched fingerboard, a fretting block with a rubber-lined,
concave bottom can be used.
Fingerboards with bindings
require little ledges cut out at the ends of the frets so
that the fret crowns can pass over the neck binding. I
don't like binding on principle, and have compromised by
laminating rock maple binding to ebony fingerboards and
fretted the boards as usual. This method is both
decorative and functional, and results in easier and
better fret placement. It permits the fret to run the
entire width of the neck, thus preventing snagging of the
1st string on the fret ends. It is also an attractive,
clean design for a guitar neck.
Anthony developed an early
interest in guitar as a boy growing up in Argentina and
Chile. In the mid-sixties he became seriously involved in
playing, repairing and constructing guitars, and he has
been professionally repairing and building for 12 years
in Pittsburgh, PA. In his own words he is a "fanatic
when it concerns the smooth and perfect action of an
instrument."
Text From The Luthiers'
Mercantile Catalog - 1993
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