Luthier Tips du Jour - Neck Carving - O'Brien Guitars

Neck carving is probably one of the most intimidating steps
of the entire guitar building process, but it doesn’t have to be.
If you follow the steps that I am going to outline here,
you should be able to carve your guitar’s
neck with no problem.
The question I get most often is:
“Should I carve the neck on or off the guitar?”
Well, which came first the chicken or the egg?
If a tree falls in the woods and no one is around to hear it does it make a sound?
Does a snake have lips?
Well, you get the idea.
It doesn’t really matter.
The process of carving the neck is the same
whether on or off the guitar.
So find a way that works best for you
and go with it.
Here are some basic tools you will need to carve your neck.
A square or straightedge,
a sharp chisel or two,
a spokeshave, a rasp, and a contour gauge.
There are many ways to carve a neck.
The method I am going to show here is one that has worked well
for me over the years.
I start by clamping the neck in a vise
and in my case here I put a stool under the guitar body
so I don’t have any unpleasant surprises.
With the heel cap in place,
I begin shaping the heel block with a chisel.
I continue working until the heel block is flush with the heel cap.
Notice how I am angling my chisel as I work so that if it slips
it goes away from the guitar body and not into it.
I now turn the guitar body over and clamp it in the vise so
that I can work on the fretboard side of the neck.
I have placed a spacer block in my vise to give me adequate clearance from my bench.
I now use my chisel to begin removing the excess neck wood
until it is flush with the fretboard.
With the heel block flush with the fretboard
and heel cap, the middle is high,
as you can see when placing a straightedge on the heel block.
I then begin removing this area of the heel block with my chisel.
I keep removing material until this area is flat.
Placing a straightedge along the heel block will let you know when it is flat.
Work carefully and take small bites with the chisel
so you don’t chip out pieces of the heel block.
Now I use my chisel to remove about one millimeter of material
in the middle of the heel block.
This gives me a small relief
and it isn’t much as you can tell.
Since the heel block has two sides,
it’s necessary to do this same process on both sides.
First, start by using the chisel to make the heel block flush with the heel cap.
Then turn the guitar over and make the heel block flush with the fretboard.
Then carve the middle of the heel block down
until it is flat and then a skoshe more so that you have a slight relief.
The trick here is to make both sides symmetrical
and this is where the contour gauge really shines.
Placing the contour gauge against the heel block on one side
will measure the pattern. You can then flip it over
and put it on the other side to see if they are indeed symmetrical.
With the heel blocked shaped, I now make the sides of the neck
flush with the fretboard.
A spokeshave works well for this.
To avoid damaging the side of the fretboard with the spokeshave,
I like to leave just a bit of neck wood and then use a scraper
to make it flush with the fretboard.
You could also use a flush trim bit and a router to do this.
However, be extremely careful as you can ruin your guitar neck
or other parts of your anatomy in a hurry.
I find a spokeshave works really well.
Once the sides of the neck are flush with the fretboard,
I use my chisel to shape the neck as it transitions into the peghead.
I take my time here cause I want the nut to be flush with the neck
and not flare out as it transitions into the peghead.
A scraper can be used here as well.
Once again, do this step on both sides of the neck.
I am now ready to carve the contour of the neck.
Start by using a rasp to thickness the neck at the nut or first fret.
This area will serve as a point of reference while carving.
On my guitar here I am thicknessing to a rough measurement of 22 mm. or .86
Later I will final sand to a measurement of 21mm. or about .82
I do the same thing at about the 10th or 11th fret
but this time I will go to a rough thickness of 25mm or .98
and later finish sand to 24mm or .94.
A rasp works really well for shaping the heel block
as it transitions in to the rest of the neck.
I start by using the course side of the rasp and finish with the smooth side.
To carve the rest of the neck I need to secure the guitar.
A vacuum jig works really well for this or you can place the guitar on a workbench
face down and use your body to help hold it in place.
I now use my spokeshave to begin rounding the neck to the shape I like.
It is very important that you work with sharp tools while carving your neck.
I like to round the neck first and then remove material uniformly
until I get to the target thickness areas that I made at the nut
and at about the 10th and 11th frets.
You can use a commercial neck radius template like this one
to check your progress as you go.
These templates are available in a variety of popular neck contours.
You could also make your own templates from an existing guitar
by using a little bondo, some MDF and a few minutes of your time.
Continue removing material with the spokeshave.
The objective is to make the neck round,
so I take more from the left and the right side of the center
than I do in the middle of the neck.
Periodically stop and place a straightedge along the neck
to make sure it stays flat.
I do this along the centerline and on both edges.
Also, check the neck often with your neck template.
On the nut end of the neck I use a chisel to shape
the transition from the peghead to the neck.
It may appear that I am working fast, well, that’s about how fast I normally work.
However, you may want to work a little slower until you have carved a neck or two.
A scraper works great for cleaning up this area.
Continue removing material until you arrive at the points of reference
you made at the nut and the 11th fret.
Once you achieve the thickness and radius that you desire,
use a piece of 80 grit sandpaper to clean up the neck.
Only sand with the grain.
You can also spend some quality time with the sandpaper cleaning up around the heel block.
Run your hand up and down the neck slowly
to check for high or low spots as well as square edges.
Make sure you are satisfied with the way the neck feels in a playing position.
If you have a large pile of shavings on your shop floor
then you probably did it right.