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X Bracing On The Back
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=24884		 Page 1 of 1
Author:  Dan Pennington [ Fri Dec 04, 2009 9:26 am ]
Post subject:  X Bracing On The Back
I bought the Small Jumbo plans from StewMac. They show an option for x bracing the back. What are the advantages/disadvantages for doing the x bracing? Better sound? Different sound?
Author:  Michael Dale Payne [ Fri Dec 04, 2009 9:42 am ]
Post subject:  Re: X Bracing On The Back
On the SJ the X braced back is a very good option to use for two reasons.

One, the shape of the lower bout is bulbuls. With some tone woods, Mahogany in particular, the back tend to want to flatten out between the last two ladder braces over time at the mid perimeter of the lower bout. The X bracing supports the dome shape better.

Second When I originally designed the SJ (OLF-SJ to you guys ;) ) the intent of the back X bracing is the reflex cone affect. In my opinion this imparts a more balanced resonance to the guitars sound.

I should expand a little more. the major difference I notice in sound between X braced bad and ladder braced back on the SJ is it has more of tambourine like shimmer when strummed and a tad more percussive when playing individual notes when X braced.
Author:  Jake Archer [ Fri Dec 04, 2009 10:06 am ]
Post subject:  Re: X Bracing On The Back
I will say that I have used X-bracing on the last 4 of the 9 guitars I've made, and have been very pleased with the results. It does take a little more time to get right, as far as the jointing and such, but I am pleased with the looks, integrity, and most importantly, the sound.

I strongly recommend using it for your backs as well.
Author:  Dan Pennington [ Fri Dec 04, 2009 12:36 pm ]
Post subject:  Re: X Bracing On The Back
X bracing sounds pretty good to me. I'll try it. Do you guys use back x bracing on Martin style guitars, too. The OLF SJ plans call for a 15 ft. radius back. That's a nice dome. What radius do you usually use?

I'm about to start a 00-21 12 fret style kit that I bought from Blues Creek. Any reason that I shouldn't try the x bracing on that? This will be my 4th guitar - two from scratch and one kit. So. I've got a little building experience. And I've built a million banjos.
Author:  Michael Dale Payne [ Fri Dec 04, 2009 12:53 pm ]
Post subject:  Re: X Bracing On The Back
Not sure a 00 needs it but I also doubt it would harm any either, As I show on all the OLF plans I use 15' for all backs OM and larger. I use X braced backs on OM and larger guitar unless the client request Ladder bracing. I have recently stated double X bracing tops more often than not on SJ and MJ but am torn on which sound I like best (Double X or convention X and tone bar tops) it is very easy to over brace with double X tops requiring a lot of brace carving in the lower X. But once tuned I really like the double X for finger style. But like the conventional for flat picking.
Author:  Dan Pennington [ Sat Dec 05, 2009 8:50 am ]
Post subject:  Re: X Bracing On The Back
Thanks for the advice. I think I'll wait till I do a scratch build on the OLF SJ to try the x bracing on the back. My 00-21 kit has everything arranged for ladder bracing, so I will just go with that.
Author:  j.Brown [ Sat Dec 05, 2009 10:08 pm ]
Post subject:  Re: X Bracing On The Back
Anybody got photos of their x braced backs?
Author:  GregG [ Sat Dec 05, 2009 10:27 pm ]
Post subject:  Re: X Bracing On The Back
FWIW....I like lattice braced backs better than X braced. Come to think about it I like ladder braced backs better than X as well......My favorite is lattice, but they are a pill to make.

Cheers,
Author:  Ken Franklin [ Sun Dec 06, 2009 2:54 am ]
Post subject:  Re: X Bracing On The Back
Here's a pic of a double x that I do on my SJs.
Author:  Alexandru Marian [ Sun Dec 06, 2009 6:39 am ]
Post subject:  Re: X Bracing On The Back
Ken, that looks great. May I ask what is the lining wood, and if it's 1 piece or a lamination?
Author:  Ken Franklin [ Sun Dec 06, 2009 2:23 pm ]
Post subject:  Re: X Bracing On The Back
Thanks, Alexandru. The linings are solid, bent poplar sections. I bend a whole side and then cut out the sections. They are a little hard to bend that thick but I soak them for quite a while.
Author:  Michael Dale Payne [ Mon Dec 07, 2009 10:46 am ]
Post subject:  Re: X Bracing On The Back
j.Brown wrote:
Anybody got photos of their x braced backs?

Attachment:
SJ back X.jpg
Author:  P@uL [ Mon Dec 07, 2009 12:58 pm ]
Post subject:  Re: X Bracing On The Back
looks like i did mine like Michael and i was wondering about if i needed the second ladder brace right through the waist area. looks like my suspicions were correct. i really like the looks of that double X kinda interesting.
Author:  Michael Dale Payne [ Mon Dec 07, 2009 1:13 pm ]
Post subject:  Re: X Bracing On The Back
You do not need the third ladder brace as you called it. but it does support the dome shape better than conventional ladder bracing or a singular x brace. If you are famillure with the OLF- plans you will note that I call that brace a spar braces. I does not go all the way across. it is 2 separate braces that butt into the X brace. It could be done as a full width brace but the joint would be more difficult to layout.

as i mentioned in a post a long time back. I revised the Back X bracing on the OLF plans to match what I was doing. this all came a bout from a set of mahogany that wanted to flatten out at the parameter between the ends of the X braces The spar was added originally to help support the dome shape. After building a couple this way I found I could build with slightly thinner backs and still get the bass reflex I wanted.
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