page 33
If the neck block was mistakenly tipped forward when glued
in place, the neck may be “overset” too far away from the
body. In this case, the straightedge laid on the fretboard will
extend too far above the center of the hand rest. Removing
wood from the top of the heel on both the treble and bass
sides equally will bring the neck up so the straightedge
comes down to slightly above center at the hand rest.
Use the formula in “Understanding neck angle geometry” to
determine how much wood to remove. With a sharp pencil
and a straightedge, mark the area to be chiseled away in a
straight line from the top of the heel to the zero point at the
bottom. Repeat this line on the opposite side.
The sandpaper strip described above won’t work here
because the fretboard is in the way, so you’ll need to use a
sharp chisel to remove the long taper of wood on each
cheek. Cut in the direction of the top edges. A final light,
downward pull of the sandpaper strip will clean up any
marks left by the chisel.
Here’s the way to determine how much wood must be
removed from the cheeks for the correct neck angle at the
bridge. Always remove wood gradually and check your
progress frequently. A little adjustment goes a long way! Our
example measurements below are based on the scale length
of this guitar: 25 inches.
The measurement we want is
X
— the amount of wood to
remove from the heel to change the neck angle so that a
straightedge laid on the frets will be flush with the top of the
bridge
(60)
.
A
= How far the straightedge falls below the top of the
bridge. In this example: 1/8" (.125").
B
= The heel length from the fretboard bottom to the heel
cap. In this example: 3" (3.0").
C
= The distance from the neck/body joint to the saddle. In
this example, that’s at the 14th fret, and
C
= 12-1/2" (12.5").
X
=
A
x
B
(÷)
C
In this case, those numbers are .125" x 3.0" ÷ 12.5" = .030". So
in our example
X
= .030" which is almost 1/32". This is the
amount to remove at the bottom of the heel.
Neck adjustment: tilt the neck up
Understanding neck angle geometry
60.
