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Hello all. I'm getting ready to brace the back of my cocobolo-Engelmann
small jumbo, and I'm interested in a cross braced lower bout for the back.
I'm of the "let the back vibrate in sympathy with the top" school of back
bracing, so keep that in mind. I've seen pictures somewhere of a cross
braced back - I think it was here, but quite some time ago. So show me your
backs! (x-braced, that is)

How about this...it is of my 2nd guitar. It is way over braced, but this gives you an idea. Good luck!

Tracy

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Tracy
http://www.luthiersuppliers.com

Crazytooguy I hope this helps. This my SJ design other wise know as the OLF SJ. This bracing pattern is on the OLF SJ Plans available from The OLF Library of Plans. The Snake wood cap was specific for this client



You will notice it is six sided star rather than just an X. this is to help support the extreme edges of the back at the apex of the lower bouts dome from wanting to flatten out.

Here is my current build.



Similiar to Michaels but maybe a bit lighter. The cap is one piece maple shaped to an 'x' in place.

Shane

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Canada

This is on my current build, I really like the result.




Greg

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Gwaltney Guitars

Dang you guys, this stuff is artful. Very nice!

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Eagles may soar, but weasels don't get sucked into jet engines.

Ok Shane witch one of us gets to claim, whom is flattering whom you know what they say about imitating and flattery

You've all seen this pic before but this is how I do my backs.

Here's more grist for the mill. Still needs final sanding, but very close to the final dimensions. X-braces are 3/4" tall at the center.

Thanks guys! This is just what I was looking for. Really love what you all did
with the design on these. I'm also working under the impression the bracing
may improve the sound some, too. I want a very lively guitar, and my gut
feeling is the star-shaped bracing will help me get closer. Thanks again!
(and keep 'em coming! Pics like these help me get more motivated!)

Mine is similar to Pauls.

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Jim Watts
http://jameswattsguitars.com

Michael,

You have been at this a lot longer than I have, so I ain't claiming anything, but I got this design from Dan Minard....I let my x into the sides, it looks like you stop yours just before you get there...the details!

I sure like the looks of what Paul does too though!

Shane

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Canada

I'm a simple kind of guy.




Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Wow some, really elegantly carved back braces in this thread!!Sam Price39039.1490162037

This is sort of a new design for me. I used something similar a couple
years ago on an ABG and really liked how it worked. This is for an SJ, I'm
not done with this one yet, so the jury is still out. The madallion is where
the lable will go.


long

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"No man ever steps in the same river twice, for it's not the same river and he's not the same man.” -Heraclitus of Ephesus

WOW! VERY nice work on the back braces folks!

Michael, like Hesh said, love the chocolate cap!

Shane, that looks great too buddy! And everyone one else too BTSW!

Cann't wait to be shaving those SJ braces too, just finished the rosette last night, if my camera would still be working, i'd have a pic!

Keep the pics coming guys!

Yesterday, I posted a discussion on the "What about the sides?" thread outlining my theory of how the back functions and how it is affected by the braces. I was talking about standard ladder bracing, but the theory applies to X braced backs, too.

The first X braced back I saw was close to 15 years ago on a box built by Harvey Leach. It had just one big X, nothing else, and had, mainly, a loud bottom E string. I attributed this to the fact that there was little restricting the perimeter of the lower bout from vibrating.

These photos all show beautifully crafted braces, and Bruce gets the parabolic prize. But, IMO, they are all too heavy to allow the back to really work as I described in my previous post.

I built two with X braced backs, and was concerned about the unsupported parts, especially the diamond area between the X in the lower bout, and the one in the upper. I used a small lateral brace in between them .

Overall, I was able to get the same reinforcement as with standard ladder bracing, but the braces ended up much smaller than those shown here by the time I worked them down enough.

They are different, beautiful, and bound to attract the eye of a buyer or another luthier, but I concluded they were not worth the trouble, and didn't give as much overall support as standard back bracing.

Parade rainer,

Scott

Hi Scott,

I'm always interested in your thoughts, I read about your work quite a bit before starting my building journey. I too was thinking(by listening) that my "X" braced back was a tad large and have since trimmed it a bit from the pics shown above. Interestingly enough the tap/tone/vibrancy of this design seems to be superior to the ladder braced backs I've worked with(albeit limited)....if a moving back is your thing? And yes, it is a lot more work, no doubt, anyway, seems worth it to me a this point. Appreciate your comments, keep them coming.

Greg

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Gwaltney Guitars

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

[QUOTE=Scott van Linge] These photos all show beautifully crafted braces, and Bruce gets the parabolic prize. But, IMO, they are all too heavy to allow the back to really work as I described in my previous post.
Scott[/QUOTE]

Thanks, Scott, parabolic was exactly what I was shooting for. This is only my 4th guitar so I don't know what I'm doing yet.   I have read many of the theories and I'm absolutly certain that stiff backs are necessary for world-class instruments. However, I have also read that the path to incredible sound comes from flexible backs as you describe. I've even read that some builders start with one type and then convert to the other during their careers; all the while building the best instruments ever that capture the essence of that untimate vintage sound combined with purity of tone necessary for today's modern styles.

Please note that this is not directed at you. In fact, I've braced my top with parabolic bracing after reading some of your (and Colin's) posts touting parabolic bracing. It just reflects my confusion on the issue.

[QUOTE=Scott van Linge] Yesterday, I posted a discussion on the "What about the sides?" thread outlining my theory of how the back functions and how it is affected by the braces. I was talking about standard ladder bracing, but the theory applies to X braced backs, too.

These photos all show beautifully crafted braces, and Bruce gets the parabolic prize. But, IMO, they are all too heavy to allow the back to really work as I described in my previous post.

I built two with X braced backs, and was concerned about the unsupported parts, especially the diamond area between the X in the lower bout, and the one in the upper. I used a small lateral brace in between them .

Overall, I was able to get the same reinforcement as with standard ladder bracing, but the braces ended up much smaller than those shown here by the time I worked them down enough.

Scott[/QUOTE]

Scott, maybe we aren't trying to get the back to work the way you described. I've made 20 or so now with X-braced backs and have honed the process to the way I like the back to work.

There are, as you will be aware, two main schools of thought on what the back does, it can be made either active or passive. On steel strings I prefer passive as the guitar is usually held firmly against the player and will be damped to some degree by a 140lb brace. I use an X-brace on my steel strings as I believe that it holds the radius better longditudinally rather than just forcing it in when gluing to the rim.

I do own three 1930s golden era Martins (they are now solely part of my pension fund) but prefer the sound of my guitars because they have been tailored to my needs for the types of music I play.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Guys,

I like the look of the x-braced backs, good work. Seems that x-bracing is getting mighty popular.

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Joe Beaver
Maker of Sawdust

Further thotzz:

If you are of the tight back way of building, I think that X braced backs could easily be better in focusing the reinforcement for each bout.

Which brings the question of whether to use two Xs or one, as does Dave and Bob (maybe more--the pix don't all come up now). The first X braced back I saw was on a Harvey Leach guitar in about 1990. It had a lot of bass, and used one X. This of course allowed much of the lower bout more complete freedom to reinforce, but didn't provide much strength.

From my controversial perspective , a single X will try to force the back to vibrate as a whole, with the center of rings at the cross point, as on the top. If the upper and lower bouts want to vibrate as separate systems, as I can feel with my fingers on "loose backs", a single X might confuse the zoot. We're all still learning.

Has anyone compared boxes built with one vs. two back Xs?

Last weekend, a friend visited, bringing a Taylor 110, their low end dread with a molded back, no braces. I hadn't seen one before, but was not surprised to find that it gave great reinforcement and vibrated against my 180 pound, semi-parabolic brace...

I've revoiced several Guilds with the molded backs, and feel these low end jobs had more bass and mid range than their braced counterparts to begin with. Of course, they did not allow for any further reinforcement that braced backs provided, once the braces were reshaped parabolically and reduced until they allowed complete vibration over their entire lengths.

For me, this shows the advantage of loose backs, but I would love to play some of these beauties and just listen carefully.

Colin, since you have three vintage Martins, can you comment on whether the back braces are parabolic? And you could also look inside with a mirror and note whether the side/finger braces are parabolic, and maybe the arms of the top's X?

Scott

PS: I am only offering a way to analyze and understand how to change the sound and/or balance if that is something you want to do, and take no offense with anyone who doesn't buy my theories. After all, I'm not selling anything, and I'm here to learn. S

Scott, don't worry I'm an advocate of something approaching your system! As many here will tell you and noted by Bruce above I have been a great fan of "parabolic" bracing for many years. It is probably more popular on this side of the pond than on your's, as it suits the Celtic styles of playing and the more attacking modern styles of play popular here. I've built a lot of guitars that way and tune the top plate in a similar (though not same) way as you do. I don't say I fully agree with you on everything (we'll debate that another day!) but I think your work is both thought provoking and interesting.

By the way this is the top plate for that Walnut OM above, it will be my new dedicated DADGad guitar. As you can see we have ended up in the same ballpark, coming from different directions.



ColinColin S39042.482025463

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.