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X-Braces and guitar side relationship
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=28663		 Page 1 of 1
Author:  Gregg C [ Wed Aug 18, 2010 11:26 am ]
Post subject:  X-Braces and guitar side relationship
Good morning guys,
I've seen the guitar sides notched out for the X-Braces to sit in. I've also seen only the kerfing notched out (Martin Guitar Factory Tour).
And I've seen the X-Braces trimed right up to the kerfing, no notching at all.
Can someone please shed some light on this ?
Are there any articals written on this ?
Thanks
Gregg
Author:  Fred Tellier [ Wed Aug 18, 2010 11:57 am ]
Post subject:  Re: X-Braces and guitar side relationship
I used to only cut the Kerf lining like Martin but now cut through the sides on the last 4 guitars, much faster and easier to do. As for ending the brace at the lining lots of people also do that to so it must be OK. The ends of the X brace and the UTB brace are the only ones I cut into the lining and sides, all the rest are feathered flat to the top an the lining.

Fred
Author:  JohnAbercrombie [ Wed Aug 18, 2010 12:04 pm ]
Post subject:  Re: X-Braces and guitar side relationship
Fred Tellier wrote:
I used to only cut the Kerf lining like Martin but now cut through the sides on the last 4 guitars, much faster and easier to do.

[:Y:] [:Y:] [:Y:]
Author:  Laurent Brondel [ Wed Aug 18, 2010 12:05 pm ]
Post subject:  Re: X-Braces and guitar side relationship
It's good practice to feather out braces that are not tucked into the linings, leaving just enough material to go under the linings. That should prevent the joint to peel off.
Whereas you go through the sides or not when notching the linings depends on how tall your bindings or binding/purfling stacks are. Obviously when using "short" bindings (say .150" tall) you need to stop before the sides as the bindings will not hide the braces ends.
Author:  Alan Carruth [ Wed Aug 18, 2010 12:19 pm ]
Post subject:  Re: X-Braces and guitar side relationship
Guitar tops shrink across their width over time, but the braces don't get much shorter. I've seen old guitars where the shrunken tops have caused the brace ends to push against the binding, causing it to pop outward in those spots. It's actually a good idea to leave a little space between the end of the brace and the side/binding. It doesn't need to be much, but it helps.
Author:  Fred Tellier [ Wed Aug 18, 2010 12:26 pm ]
Post subject:  Re: X-Braces and guitar side relationship
Quote:
It's actually a good idea to leave a little space between the end of the brace and the side/binding


That's what I do, glad you mentioned it Alan it had slipped my mind when typing my reply.

Fred
Author:  Alexandru Marian [ Wed Aug 18, 2010 2:56 pm ]
Post subject:  Re: X-Braces and guitar side relationship
Here is an illustration of the problem. You can see the spruce brace. All other transverse brace ends pushed the binding out same way. The back has separated from the lining too. I am pretty sure this guitar was built in extremely high humidity, but anyway...
Author:  JohnAbercrombie [ Wed Aug 18, 2010 3:27 pm ]
Post subject:  Re: X-Braces and guitar side relationship
Alan Carruth wrote:
Guitar tops shrink across their width over time, but the braces don't get much shorter. I've seen old guitars where the shrunken tops have caused the brace ends to push against the binding, causing it to pop outward in those spots. It's actually a good idea to leave a little space between the end of the brace and the side/binding. It doesn't need to be much, but it helps.


That's an interesting observation.
The top/brace glue joint must have failed before the top could pull away from the binding??
I don't see how the top, glued to the brace, could get any narrower...did the glue joint creep?

It would be easy enough to test, I guess- some day I'll glue a brace cross-grain on a scrap piece of top, and see what happens when I dry it at v. low humidity. Some day.....

Cheers
John
Author:  Gregg C [ Thu Aug 19, 2010 6:06 am ]
Post subject:  Re: X-Braces and guitar side relationship
So far this discussion has been about structure, how about sound ??
I would think notching the sides would tighten / restrict the top ??
Yes / no ??

Gregg
Author:  bluescreek [ Thu Aug 19, 2010 8:36 am ]
Post subject:  Re: X-Braces and guitar side relationship
notching doesn't hurt the sound at all. I am a notcher as I have seen through cuts where a crack has started.
Author:  jfmckenna [ Thu Aug 19, 2010 9:25 am ]
Post subject:  Re: X-Braces and guitar side relationship
I've given this a lot of thought my self. I always cut the linings right off and but the brace end to the sides ( will definitely be leaving a little space there now thanks to this thread) then glue a kerf down on top of it as seen in Cumpliano and Nattleson's book. But when I think about it it seems to me that feathering the end right to the lining and not notching it at all has an advantage. Why do we notch the brace? I'm guessing the idea is that it will keep the joint held down a bit better in the event of a blow to the top. Well what if the joint actually does brake? The notch would keep the brace flush there by hiding the fact that it's actually broken away. But without the notch the brace would pop and the repair is relatively simple.

I still notch though it's food for thought, or not :)

Oh and as for the back I definitely notch because I like the look of it.
Author:  Laurent Brondel [ Thu Aug 19, 2010 9:58 am ]
Post subject:  Re: X-Braces and guitar side relationship
JohnAbercrombie wrote:
The top/brace glue joint must have failed before the top could pull away from the binding??
I don't see how the top, glued to the brace, could get any narrower...did the glue joint creep?
It's fairly common: as the top, back, and to a lesser extent sides, shrunk accross the grain, the braces didn't (along the grain). Wood doesn't shrink much, if at all, longitudinally.
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