Guitar Tricks Insider February/March Digital Edition | Page 49

GUITAR TECH

GUITAR TECH ANSWERS:
As you may know, there are three
adjustments for setting a guitar’s action:
1. adjusting the neck’s truss rod, 2. setting
the string heights at the bridge saddle, and
3. re-cutting the slots in the nut to set the
correct action in the lower register of the
fingerboard (the area closest to the nut).
Begin by evaluating the action to see where
the problem lies. Start by installing and
stretching a fresh set of strings. Worn strings
can’t be used for this method.
Next, install a capo at the first fret. This will
take the action at the nut out of the picture,
so you can clearly evaluate the neck’s truss
rod and the bridge-saddle height. If the
action is better after installing the capo this
means the string-slots in the nut are too
high, and they will need to be re-cut before
the setup process is complete.
Next, check the neck’s relief (forward
‘bow’), so that you can adjust the truss rod
if necessary. To do this, fret the 6th string
at the top fret and see how big the gap is
between the string and the frets around
the middle of the fingerboard (around the
9th fret). Since you already have the string
capoed, fretting the string at the other end
of the fingerboard will result in the string
more-or-less touching all the frets. If there’s
a gap of more than around .015” between
the string and middle frets, then there’s too
much relief in the fingerboard, and the truss
rod probably needs tightening. If the gap is
between .005” and .015”, the truss rod is
just about perfect. If there’s no gap – the
strings are touching all the frets – you need
to loosen the truss rod. Without seeing your
Seagull, most acoustic flat-tops have their
adjustment nuts located on the body-end
of the neck (accessed via the sound-hole).
Some have their adjustment-huts located on
the headstock under a cover-plate.

FEB/MAR

Once you’ve adjusted your guitar’s truss
rod, play the guitar (still capoed) to see
whether the action is satisfactory. If it’s still
too high, you’ll want to lower the saddle
by removing material from either its top
or bottom surface. Take your instrument
to a repair shop if you’re not comfortable
with removing material from the saddle.
Otherwise, determining how much material
to remove requires careful measuring of the
existing action (still capoed!) followed by a
fairly simple calculation.
Here’s how: measure the 6th string’s action
at the 13th fret using an accurate measuring
tool like the Stew-Mac String Action Gauge to
establish a baseline. Next, press the 6th
string down just in front of the saddle until
the action seems about right – in the middlerange of the fingerboard. Then, while holding
the string in that position, note the new
action measurement at the 13th fret. To
create this difference in the action, you will
have to shave the saddle down approximately
twice as much as the measured difference
between your baseline measurement and
your preferred action measurement. E.g., say
you measured .100” at the 13th fret to start,
and your preferred measurement at the 13th
fret is .070”. This is a .030” difference at the
13th fret. To achieve that much change at
the 13th fret, you will have to remove almost
.060” at the saddle, because the 13th fret is
halfway from the saddle back to the 1st fret,
where your change-in-action at the saddle
will have almost no effect. Obviously, it’s best
to proceed cautiously. But it’s not the end of
the world if you make a mistake.
Once you’ve lowered the saddle to your
preferred height, turn your attention to the
nut. In this case, I strongly recommend
taking your instrument to a professional.
Unless you have a full set of nut-slot files,
you can’t do this job correctly. However, if
your action is too high at the nut, correcting
it will truly transform the guitar’s playability.
Hope that helps! ■

DIGITAL EDITION

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