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I am getting ready to build a Small Jumbo. I have built five or six of these guitars and they turn out to be a really nice guitar....The guy who wants it made is also requesting a neck join at the twelfth fret...I explained to him that the bridge will move forward about 1 1/2" and will not sit on the x bracing , maybe causing some early bellying problems.... I don,t want to change the X bracing angle or move it forward, since I feel this will make a difference to the sound....An option i am looking at is going with a shorter scale ....what are you thoughts on all of this?...Tks

Placement of the X-brace ALWAYS needs to support the bridge location, which is determined by the scale length and neck joint.

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What Rod says. Also, unless you go to a really short scale you will end up moving the bridge anyway. One option is to move the upper bout up to meet the 12th fret rather than moving the neck into the body - compare an OM with a 12 fret 000 and you'll see that the 14 fret OM is much flatter on the end.

Scale length can influence a lot of other things - string tension obviously, but some people feel it has an effect on tone (ratio of partials and overtones). What scale do you currently use and what do you want to go to.

Not sure what other people think but I would try and steer your client away from a 12th fret small jumbo. Sort of defeats the purpose of a small jumbo sized guitar.... but I’ve never built a 12 fret body joint guitar so take that for what it’s worth.


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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Rod, Yeah, I have already mentioned to him that he may have to go with plan scale...

Freeman....Scale for the SJ is 25.34.....The guy who wants the guitar builtwants to go with 24.75".....With that scale the corners of the bridge just barely cross the X-Bracing and one of the pin holes go through a tone bar....

Lab, you could certainly make a 12th fret and adjust the locations of the bracing for that and a shorter scale. It won't be too far off your standard and might be a good arrow for your quiver.

http://forum.gibson.com/index.php?/topi ... s-14-fret/

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

You know, if you get the G Thang software, you can play around with all sorts of things, like where the waist and the soundhole go. I designed a 13 fret guitar with a standard Martin scale (25.34") and put the bridge right where I wanted it. This level of freedom could allow you to design a 12 fret small jumbo with the bridge in the right place and the X brace in the right place. Just a thought.

Hey Larry,
Moving the bridge tailward by the two frets worth will imo be a bigger sound changer than altering the bracing a little. A 12 fretter will
sound different than a 14 fretter by this scenario alone. Not a bad thing either. My advice would be to leave same scale as you would normally use, move the bracing half the distance or all you can tolerate and decrease the splay a couple or three degrees to catch the bridge wings. You may be pleasantly surprised by the outcome.
The last two guitars I built were 12 fretters and to my ears are the best sounding ones I have built. They were not X braced however
but are similar in size to a SJ.

Thanks guys for you thoughts and ideas on this....

Ken ...I am in Mount Pearl at least once a month....I would like to drop by your shop and have a chat ,next time I visit with the kids

We've built the SJ to 12 fret in 25.4" scale and in 14 fret at shorter scales, such as 24.75", and the instruments were well received. If you'd like a tracing of the bracing from the template, plus build notes, just PM me with your address and I will get them over to you.





From my notes, the general procedure for converting a 14 fret body pattern to 12 fret without a body shape change is as follows:

- On a body outline, locate where the bridge must be for the selected scale length and number of frets, and draw it in full scale with saddle slot.
- Determine the number of frets and do a full scale layout of the fretboard extension on the body outline.
- Place the soundhole such that the extension covers the joint on the planned rosette
- Place the UTB under the end of the fretboard and at least 3/8" above the edge of the soundhole
- Draw in the X so that the upper arms terminate within an inch of the UTB and the lower arms support the bridge wing where the upper edge of the lower x arms passes through the bridge wing corner away from the soundhole on a belly-style bridge.
- Place the bridge plate to fully support the bridge (usually 1/8" to 1/4" forward of the bridge and 1/8" to 1/4" behind the bridge.
- Adjust tone bars and finger brace angles and locations to provide similar support as with the 14 fret instrument.
- Add UTG and soundhole bracing as desired.

This method honors the physical realities of where major components need to go, and is a starting point for optimizing the layout for construction, but is certainly not an optimized layout.

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"Ken ...I am in Mount Pearl at least once a month....I would like to drop by your shop and have a chat ,next time I visit with the kids"

Sure. Anytime. I'd look forward to that.

Ok...Thank you.... I can see what you have done and will get my template and make the changes and see how it works out...Again thank you very Much