STEP
1
Measure the Action
A guitar’s action—how far the strings sit above the fretboard—determines its playability.
Our journey begins here:
1. Tune the guitar to concert pitch. If the strings
are totally shot, restring
first.
2. Clamp a capo on top of
(not behind) the 1st fret
(Photo 1). By doing
this, you create a “zero”
fret and temporarily
remove the nut from
the action equation.
This allows you to ini-
tially focus on saddle
height and neck relief.
Measure from the bottom of the string to
the top of the fret.
On Chapman’s
914, the height was
6/64" on the 1st string
and 7/64" on the 6th
string. This is very
high action!
Before measuring the action,
clamp a capo
directly on top of
the 1st fret.
1
STEP
3
Measure the Action at
the 1st Fret
Another factor in playability is
how high the strings sit in their
nut slots. If the strings are too
high, the guitar feels stiff. If they
sit too low, you’ll get a buzz
when you play the open strings.
1. Remove the capo and measure the distance between
the bottom of the 1st string
and the top of the 1st fret.
2. Repeat the process for all
six strings. When the guitar is set up properly, the
gap should incrementally
increase from the 1st to
the 6th string to accommodate their progressively
thicker gauges.
At the 914’s 1st fret,
the 1st string was 2/64"
above the fret and the
6th string measured just
over 2/64". Again, this is
rather high, especially on
the treble strings.
STEP
2
Measure the Neck Relief
It’s important to determine if the neck has forward (concave) or backward (convex) bow.
Along with saddle height, neck relief also affects the guitar’s action. Here’s the process:
1. With the capo still
clamped on top of
the 1st fret, hold
down the 6th string at
the 14th fret.
2. Measure the greatest
distance between the
bottom of the string
and the top of the
frets (Photo 2). The
largest gap typically
occurs somewhere
between the 7th and
9th frets—essentially
in the middle of the
neck.
Measuring
neck relief
with an action gauge.
2
STEP
4
Check the Intonation
Next, I use a strobe tuner to
check the intonation. Here’s
how it works:
1. Tune each string with
the strobe using 12th-fret
harmonics.
2. Starting with the 1st string,
play the 12th-fret har-
monic as a reference and
then fret the same note.
The goal is to have the
fretted note match the har-
monic. If the fretted note
is sharp or flat, write down
how many cents (plus or
minus) it deviates from
the reference harmonic.
3. Repeat the process for
strings 2-6. Double-check
the tuning of each reference
harmonic as you work your
way across the fretboard.
On Chapman’s gui-
tar, I found most of the
strings were sharp when
played at the 12th fret,
and the amount varied
from + 2 to + 6 cents.
