MEANGENE
So You Want to Build a Guitar? Pt. 7
Rear Routes Final Body Routes
Things start moving quickly at this point as Now we put our first fixture back on to com-we see the guitar really starting to form. plete the control cavity, pickup routes, input
We are going to be flipping the guitar face jack, top tremolo route and the body perim-down – this is where our tooling holes help eter, all using a 1/2” end mill. We currently
align everything for the routing operations. have all three of our tooling holes in use
We lose access to the third tooling hole during this operation until the body shape
on the rear of the headstock while upside is completely cut out. If routing manually, a
down, but by recessing the fretboard into hand-held plunge router using 1/2” router
the fixture it helps keep everything lined-up bits with 1/2” bearings will do the job nicely
during machining. for pickups, controls and tremolo routes.
A standard table router (hand-held router
mounted upside down in a stand or tabletop)
is great for routing body shapes. If you
about an inch shy of the nut. Once complete, we freehand the final excess material
as it slopes into the neck’s back shape with
the bandsaw.
Then it’s back to the CNC – I use a jig that
has a relief cut for both the front and rear of
the headstock so the head self-aligns easily.
For the first operation, place the headstock
face down and fly cut the rear to a final thickness of .580” using a 2” diameter fly cutter.
Drilling tuner holes on an angled fixture
The guitar, taking shape, but
before contouring
Tummy Contour and Neck Shape
This is the single, longest running machine
program for me, taking approximately 30
minutes to cut the tummy contour and the
neck shape using a 5/8” ball nose cutter. If
you’re doing this manually you can rough-in
the tummy contour by slicing it on a bandsaw while attached to an angled jig. The jig
is simple – two flat boards, two hinges, an
angle adjustment and then lock it in place.
Trace your final tummy contour shape from
the rear and side view and saw as close to
the lines as you are able. With a little finesse,
you can also sand the final shape into the
contour with a spindle or edge sander by
employing the same angle jig.
have a pin router, you’re loving life and can
sail through many of these operations like
a human CNC with better quality cuts than
hand routers and bearing cutters.
Thicknessing the headstock
The headstock thickness could also be fly cut
manually on a drill press with a Wagner Safe-T Planer.
The Headstock
There are a few steps to finalizing the headstock. First is drilling our tuners. We have a
flat surface on the rear of the headstock, but
we also have the 12 degree headstock pitch
to deal with. We already have a center mark
for our tuner locations from earlier, so we will
drill using a 25/64” brad point drill bit to a
minimum depth of .750” for a set of locking
Sperzel tuners. For this we need to have an
angled fixture to get our headstock square
to the drill bit, so we have a 12 degree ramp
pinned in place on the table; just slide the
guitar around to drill all six tuners.
Finally, we flip the headstock around – face
up – and route the pocket to drop in our
gold pearl b3 logo using a .031” end mill.
Any headstock inlays could be routed using a
Dremel tool with router base.
Next month we’ll get to all the final hand
operations as we get this baby ready for the
paint department.
Routing the rear tremolo cavity is all that is
left, so we can flip it back over for the home
strech. This is performed using a 1/2” end
mill to route the spring cavity and the deeper
tremolo block cavity.
Next we move over to the bandsaw, place
the face of the headstock against the fence
and resaw our headstock to a thickness of
.700”, cutting from the tip of the head to
Gene Baker
Any questions or comments visit
finetunedinstruments.com
meangene.org
b3gene@verizon.net
Fine Tuned Instruments LLC,
home of his “b3” instruments.
