1. Using a custom sanding block to remove old glue and level any raised wood fibers. 2. Referencing
the original and replacement top bracing with a thickness caliper. 3. The gently curved blade
on this guitar-brace chisel makes it easier to trim and shape the new braces to match the originals.
4. My custom workstation made from a shaped piece of Formica countertop attached to a ShopStand and Guitar Repair Vise from Stew-Mac.
In my previous column, I described how
a 1977 D-35 arrived at our shop with
a big hole in its Sitka spruce soundboard.
After concluding that the damage was so
severe that the top could not be restored
without compromising the guitar’s sound—not to mention its looks—I began the process
of outfitting this fine instrument with a
replacement soundboard I’d purchased from
Martin more than 10 years ago.
After removing the ebony bridge and
mahogany neck, and then separating the
original soundboard from the body, I was
ready to clean and remove any old glue or
raised wood fibers from the kerfing, neck
block, and tail block.
I made a leveling sanding block from
materials I had laying around the shop.
For the platform, I used a long rectangular
piece of Corian. First I leveled the 1/2"
plank using my thickness sander and then
I attached a soft rubber handle. To the bottom
of this 26" long custom sanding block,
I attached a length of 220-grit Stikit Gold
self-adhesive abrasive paper (item #5768 at
stewmac.com). This is the perfect grit and
material for the job.
To stabilize the body on my workbench,
I used a plywood cradle (#5657)
and body support blocks (#5656), both of
which are replacement parts for StewMac’s
TrueChannel routing jig. I’ve discovered
that many jigs and tools can be used in
other ways than originally intended. I’m
sure many of you have come across this
and perhaps you’ve adapted tools this way
too. Using a gentle back and forth motion,
I used the sanding block to square the top
surface of the kerfing.
I’m really excited about my new workstation.
It consists of a Formica countertop
shaped like a dreadnought top that’s
attached to the ShopStand and Guitar
Repair Vise (#5391). This is just the cat’s
meow for freeing up needed work space at
my bench. The best part of this workstation
is how much easier it makes gluing, clamping,
and carving braces.
For starters, the height of the ShopStand
is adjustable and that really takes the stress
off my back. Also, if you’re looking for a
good source of Formica, check out your
local businesses that install countertops.
The sink cutouts are usually taking up
space and collecting dust and the staff is
usually more then happy to move them out.
The sink cutouts are perfect for band sawing
out the work platform, as well as many
other uses in my shop.
With a thickness caliper (#5193), I
measured the original top braces and then
used a guitar-brace chisel (#1629) to trim
the braces on Martin’s replacement top to
closely match the originals. This chisel has a
specially curved blade that makes it easier to
carve the smooth curves needed for scalloped
braces and tone bars with feathered ends.
Diamond fret levelers (#5259) work
well for keeping my chisels sharp in the
shop. I do like to finalize the cutting
edge with an 8000-grit Japanese water
stone, which is available online from both
Woodcraft Supply and Luthiers Mercantile
International.
Here’s a tip: When working with
extremely sharp tools, I often wear a safety
glove made of Kevlar, Spectra, and stainless
steel to protect my hand and fingers. I
know a few too many people who have
slipped with a chisel for the first time, causing
severe tendon damage followed by surgery.
Safety, safety, safety!
With a very busy schedule, it’s hard
to make the time to keep chisels sharp.
But remember that a dull chisel needs an
increase of pushing pressure and that can
invite accidents. A well-sharpened edge
allows the tool to do the work—a better
situation for you.
I hope this column has provided you
some enjoyment and invaluable insight
into the beginning stages of retopping this
1977 Martin D-35. Looking forward to
next month!
John Brown is the
inventor of the Fretted/Less
bass. He owns and operates
Brown’s Guitar Factory,
a guitar manufacturing,
repair, and restoration facility
staffed by a team of talented
luthiers. His guitar-tool and accessory designs
are used by builders all over the world. Visit
brownsguitarfactory.com or email John at
info@brownsguitarfactory.com.