Twin Sisters Build for Memphis Guitar Festival

[George Leach]

This will describe the building of a Nylon String OM and a Jazz Classical, known as the "Twin Sisters".

We start out with sides and back of Amazon rosewood. The sides have been bent, and they are clamped into their respective molds. The backs have been glued, and are shown in the foreground.


Next, we see the tops, being glued up. The Nylon String OM top is Englemann spruce, and the Jazz Classical top is German spruce.


Now, we start working on the rosettes. Here, I'm slicing some tiles of Macassar ebony off a small billet


In this photo, the inside radius is being sanded onto one of the tiles.


Now, the outside radius is sanded.


After some sanding and pattern matching, here is the basic Jazz Classical rosette, with small pieces of bone separating the tiles. A lot of inlay is going to be done in this rosette, so it is being held in a piece of MDF, with the rosette shape cut into it.


Starting to cut reconstituted stone for inlay:


Here are the first few patterns inlaid into the first tile:


Here is the first tile, done-notice some of the inlaid pieces go past the edges of the tile. All the tiles will have to have their inside and outside radii re-sanded- as well as the edges that butt up against the bone pieces.


Here are all the tiles, completed, also showing some of the reconstituted stone used. Abalone and MOP was also used in this inlay.


Here is the Nylon String OM rosette-similar, but a thinner ring-more consistent with our steel string guitars.


This is the final Jazz Classical rosette as shown above, but with b/w/b purfling strips on the inside and outside of the rosette.


Shown here is the final Nylon String OM rosette..


Now, clamping up the braces on the go-bar deck:


Carving the braces using a curved sole plane:

[naccoachbob]

Love the rosettes, George. Are they eccentric or is that the camera angle? Very nice designs. Can't wait to see this progress.
Bob

[George Leach]

Thanks Bob,
The rosettes were actually created to be similar to the drawings of Frank Lloyd Wright. We had a customer request to do a design like this, so my former business partner and I worked to make designs that were similar to Mr. Wright's designs, but didn't actually copy anything (we didn't want legal problems). So we made the rosette designs, and designs for fingerboard markers. At some point soon, when I finish my 25th anniversary archtop, I'll show the fret markers with that build.

[George Leach]

Continuing the thread...

Here is the final Jazz Classical bracing pattern:


Now, to put the top aside and move to the body. Note we have removed the clamps and have put go-bars to hold the sides tightly to the mold. I am chalking the top of the side, and will sand it using a 25' hollow mold to put the required 25' radius profile onto the sides.


Now, sanding the profile onto the side. All my guitars have a 25' radius spherical top.


Using a curved sole plane to put the shape of the top bevel into the guitar side.


Here is the final shape of the side-for the top bevel.


Carving the back bevel:


Gluing on basswood bevel backing material:


Starting to glue in the kerf:


After Kerf is in, re-profiling the sides (both top and back) to a 25' radius:


With the sides done, gluing in the back braces on both guitars:


Shaping the back braces with a curved sole plane:


After fitting the braces into the kerf, I'm marking where the back bevel will go using a template:


Sanding the back to match the template mark:


Here's the final shape of the back-including the bevel:

[George Leach]

Continuing the thread....

Now on the top, marking the position of the bevel on the top:


Sanding the top to the marked line:


Gluing on the back:


Gluing on the top:


After the glue dries, trimming the overhang on the top and the back:


Once the edges are trimmed, cutting the end graft:


Here's the finished end graft:


Cutting the binding and purfling slots:


Gluing on the purflings on the bevel side:


After gluing on a couple of layers of sacrificial wood next to the purflings, starting to carve the bevels:


Gluing and strapping down the bindings and purflings:


Gluing on the top bevel:


Gluing on the back bevel:

[George Leach]

Continuing the thread:

After the glue is dry, scraping back the overhang:


Here are the twin sisters-Nylon String OM on the left, Jazz Classical on the right


Here are the back bevels:


One more view:


Time to start on the neck. The neck is a 5 piece sandwich, with mahogany on the outside, flamed maple on the inside, separated by thin pieces of walnut.


Cutting the fret slots. Both guitars will have a 650mm scale length.


After gluing on the headstock laminates, sanding the headstock to thickness:


Here is the headstock, after tuning machine holes have been drilled:


After the slots have been cut:


After inlay-The Nylon String OM is on top with abalone and MOP, and the bird's tail extending down the fingerboard. The Jazz Classical is underneath it,and uses Maple, Paduk, and Osage orange for its different colors:


Now, using a file to taper the slots:


Starting to fit the neck. The fingerboard extension and fingerboard have been glued to the neck, and we are marking the fingerboard extension to fit to the top:


Trimming the fingerboard extension to the line just drawn:


Checking the fit:


Checking alignment:

[stringman5]

Beautiful work, George. How would you characterize the differences in sound between the two designs? Would each model be better suited for different musical genres or playing styles?

[George Leach]

Thank you. As for the sound of the guitars, since the Jazz Classical has a 12 fret neck, the bridge is very much in the sweet spot. Its sound is more powerful than that of the Nylon String OM. However, despite that, the Nylon String OM still has a lot of sound-just not quite as much. I designed the Nylon String OM to be a true crossover--for the steel string player who likes the sound of nylon, but doesn't like the classical neck. The Jazz Classical is a true classical, but has a "C" profile on the neck, so to many, it's more comfortable to play--but it's not "traditional".--So I guess for someone who's really into soloing, and needs acoustic power, the Jazz Classical would be the answer--We've put narrower necks on them, when people don't care as much for the wide fingerboard. The Nylon String OM is very comfortable, and familiar feeling to steel string people.

Did that answer your question?

[stringman5]

Thanks George!

[George Leach]

Continuing the Thread...

Starting to carve the neck--with a Stanley Sureform tool, followed by files:


Marking the volute:


Using a flat sanding block to be sure the neck is straight:


Using a piece of sandpaper to continue sanding the neck:


Using a template to be sure the radius of the neck is right-at different points along the neck:


Checking the neck thickness with a caliper:


Blending in the volute with a file:


Now, before we complete the carving of the heel, we must make the final fit of the neck-first the side to side fit:


Then the vertical fit:


With the neck on, we carefully mark where we want to trim the heel-with a chisel:


Now, we put the neck into our heel jig (copied with permission from Michael Bashkin):


After the heel position is measured, we use a router to trim the heel at the proper point:


Once the heel is trimmed, we then glue on the heel cap (which has layers of purfling matching the side purfling), then we carve the heel.


At this point, we're doing final sanding, getting ready for finish:


Final sanding on the body, and we're ready to spray:

[George Leach]

Continuing the thread:

After spraying a few coats, the Nylon String OM and the Jazz Classical and their necks hang to dry. The spray booth is on the right.


After spraying, I'm doing some hand sanding to level the surface:


Next, buffing:


After buffing, time to glue on the neck:


Now, gluing on the bridge:


Finally, Here's the final Nylon String OM:


Another view:


Here's a view of the Nylon String OM, the Jazz Classical, and an archtop I took with me to Memphis:

[George Leach]

Here is a video of the Nylon String OM from the Twin Sisters. This is played by Paul Asbell at the Memphis Guitar Festival.

There seems to be an issue embedding the link. So here is the direct link to YouTube.

https://youtu.be/2lFC_F0E_G8