Fabrice's 8 String Short Scale Small Guitar
Awhile back I received an inquiry from Fabrice Medio about the possibility of making an eight string instrument for the baroque music he enjoys playing on the square in Mill Valley. He had been making do with an eight string guitar he had adapted by drilling holes in the neck to attach a permanent capo at the fifth fret. It was less than ideal. He liked the sound of a Kamaka baritone ukulele he had and was wondering if I could make him something similar but with an 8 string neck tuned D-E-A-D-G-B-E-A. I convinced him that a small guitar might be better in balancing the larger neck and giving the low D bass note more presence. I didn't have koa in sizes appropriate for the project so we settled on some acacia that is a cousin to koa. It was from a backyard tree that was being removed from a house in San Francisco. I had used some of it on a ukulele before. I like challenges that appeal to me and I have enough building experience to think that this should end well.
Here are the top and back, joined, cut out and thicknessed. It's a very musical wood that begs for a way to show off its voice. The tree was fast growing but quite stiff and stable. It's been seasoning for over fifteen years.
Red spruce back braces are being glued in a radiused dish.
Back braces have been carved.
I didn't have forms for this size of a guitar so I made an outside form for the project but not a form for my bender. I bent the sides and linings on a hot pipe and I added a reinforcement for a side sound port.
Here I've glued some side supports as insurance against any accident that might otherwise cause a crack to travel along the side. Probably unnecessary as this wood is very tough and resistant to splitting. The end and tail blocks are laminated with alternating grain orientation pieces to resist splitting also. The joined sides were profiled in radiused sanding dishes of 30 and 18 inches.
The first layer of linings is being glued between the side supports which are of the same thickness. The next layer will be glue over the first linings and the ends of the side supports.
The first set of braces have been glued to the top and are being carved before I glue the final set of top braces. I decided on x-bracing the top rather than fan bracing or lattice bracing which I had used on previous nylon stringed guitars because of successes I have had bracing ukuleles this way.
After I finished installing the rest of the braces I decided to install the transducers for the pickup before I glued on the top. Since there are four transducers for this JJB Prestige 430 I thought I would get better placement that way. The JJB is an excellent passive pickup with very limited feedback due to the proprietary coating of the transducers. It's very responsive even without a preamp. I only had to make sure that the endpin jack wouldn't rattle around before the instrument was complete. There was still a lot to be done.
I have let in the linings to the blocks and carved them to shape. The back is glued on to the sides and the top linings are notched ready for the top to be glued.
The box was closed and ready for binding. Unfortunately I got busy with the build and didn't take pictures of that process. It's a simple scheme of ebony without purfling to set off the acacia.
This is the beginning of my method for attaching the khaya neck. I use two bolts, one of which also attaches a strap button. There are two cross grained strips for stability that also provide a better hold for threaded inserts. The bolts allow for easier future repair if it's necessary.
I put in a truss rod that I had made for this 20 inch scale length, then glued the flat ebony fretboard to the neck. It was roughly shaped so that Fabrice could get an idea of how it would feel when it's finished. He gave me specs from his guitar that I was able to faithfully reproduce. I like to do that for players who live fairly close. He was happy with it so I finished the shaping, installed some aluminum side position markers and drilled the tuner holes.
Here is the final sanded instrument in-the-white ready for finishing. I remove the neck for that process and attach it permenantly when I'm done. I decided on a penetrating oil polyurethane varnish which protects well and can be very thin. There are no frets yet because I like to make sure that the fretboard is level before I install them.
Here are a couple of photos of the finished 8 String Short Scale Small Guitar. The tuners are Gotoh UPTLs. There's a sound sample of Bach's Prelude in Dm for Cello transposed by Fabrice.
