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I'm lucky recipient of a finished 12 fret top(thicknessed, slightly oversized, abalone rosette and soundhole cut out, not braced). I also received a finished rim that is about the size of a smaller jumbo, but a smaller upper bout(lower bout is 15" wide). I'd like to use the top for this, but there are already some reference holes predrilled where the outer bridge pins will go.

So to make this work, I was thinking of making a 13 fretter, and this will cover the holes in the top. But to do this I will need to shift all the braces down(towards the butt) about 1/2" or so. I have enough material on butt side to move the soundhole 6 1/2" from the top of the guitar. Normal for an SJ is 5 7/8" from the top of the guitar. So do I just shift all the braces down 1/2" or so, so the X brace goes over the wings of the bridge? Is this the only consideration? TIA!
TracyLuthierSupplier39079.7870486111

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Tracy
http://www.luthiersuppliers.com

You have a couple of choices; one of which you described in your post. The
other is to make the fretboard longer (add a fret for 21) which will effectively
move the soundhole toward the butt about 1/2". You can adjust this by
making the fretboard slightly longer or shorter depending on what you
need. So, moving the soundhole back by extending the fretboard should get
you to where you want to be without moving the bracing.

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Sylvan
http://www.wellsguitars.com

Sylvan,
Thanks for the reply. Let me see if I understand you...if I move the soundhole 1/2" south and make the fretboard longer, am I still connecting at the 13th fret? If so, then I am just effectively moving the soundhole closer to the X intersection right? This would be for a 25.4" scale by the way. Also, by moving the soundhole down, in what way will this affect the tone? Any idea?
Tracy

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Tracy
http://www.luthiersuppliers.com

Tracy -
What you are stumbling on is exactly how I designed my 13 fretters,
examples of which are on my web site. 25.4" scale, 21 frets. This moves the
intersection with the "X" closer to the soundhole and the angle sets the
bottom of the X right over the wings of the bridge. Of course you have to
make a neck that joins the body at the 13th fret. Makes for a very
powerful and punchy tone depending, of course, on the back and side
woods. Go to my web site and look at the 13 fret guitars closely and, good
luck with yours. I think you will really like the result. Let me know how it
turns out!Sylvan39079.9344791667

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Sylvan
http://www.wellsguitars.com

What sylvan said...

And those holes are not for bridge pin holes but rather indexing holes for a
bridge/neck set fixture.

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John Mayes
http://www.mayesluthier.com

Thanks Sylvan and John, that makes perfect sense. If I leave the X where it is, then it is about 3/4" from the bottom of the soundhole. If I use some OM plans, then the X is splayed pretty wide, and only covers the tips of a 6.5" long bridge. Should I also bring X in a little to contact more of the wings of the bridge? Also, is 6.5" too long of a bridge for a 15" bout? I'll probably use BR as the material. Thanks again for the help! Oh yea, and John, I finally realized those weren't bridge pin holes when I held a fake bridge blank up to it!
TracyLuthierSupplier39080.0878703704

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Tracy
http://www.luthiersuppliers.com

6.5 is pretty long. If you splay the x brace too much (closer in) you'll get a
very focused sounding guitar, but it may end up a little nasally
sounding if it is splayed too much. find a good compromise. Move the x
down a little and splay a little. I'd still just use a 6" bridge.

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John Mayes
http://www.mayesluthier.com

John,
That makes sense. I have another question in general...is it better to move the X brace down to cover the Bridge wings and keep a nice open splayed X brace, or to keep the X brace closer to the sound hole and bring the X in tighter to cover the bridge wings? You kind of already answered the last question, but not sure it matters how far the X intersection is from the sound hole and what difference in tone you get. Thanks for the replies!
Tracy

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Tracy
http://www.luthiersuppliers.com

the X needs to be decently close to give the soundhole protection from
cracking/damage., but you can also reinforce that with some small braces. I
would keep the angle the same, shift it and use alternate/extra
reinforcement around the soundhole.

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John Mayes
http://www.mayesluthier.com

What John just said - leave the angle alone, and move the bracing accordingly is what I do. Leaving the bracing too far back will tighten up the lower bout, reducing bass response IMO. As I mentioned in the X angle thread, I redesign all the bracing for wach new model, just form a positioning standpoint - the layout and architecture is basically the same - there is a pic in the other thread for a 14 fret 25.4 - but it really could be for anything of mine - they kinda look the same.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"