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X Bracing and it’s relevance...
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=7174		 Page 1 of 2
Author:  Sam Price [ Sat Jun 17, 2006 8:31 am ]
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I made an earlier post about bracing, and I have another question regarding an issue I have with them...

As I was gently filing away the groove to fit in the other tone-bar, my daughter fell over in the garden, I slipped and snapped my hard work in half at the groove!! (I should concentrate on my home build when the kids are in bed!)

The top X braces I have are already shaped.

As an experiment involving AR glue, a bracing blue-print and go-bars, glued the two bars onto the unbroken one, and there is success.. the join is quite strong, although there is a little wobble...

My question is; if I glued a strong peice of fabric over the join, and a very thin sliver of wood on the bottom of the braces, would this make the X bracing suitable to use on a guitar top?

If not, then why? I am open to puchasing blanks, and shaping them myself.

Sorry for asking so many questions, I rely mainly on the internet and the Cumpiano book for my guitar build.

Author:  Michael McBroom [ Sat Jun 17, 2006 9:22 am ]
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Sam,

I await answers from others here who are masters at X-bracing. I have X-braced only one guitar and got very lucky. The two pieces fit together tightly, so I didn't worry about either a fabric patch or a hardwood cap. But it is my understanding that the reason for the fabric patch or wood cap is to reinforce a joint that may have less than a perfect fit. So, in other words, if your X-braces don't fit together perfectly, I don't think it is that big of a concern. They will be glued down to the top, after all, and that will prevent movement. The fabric patch or cap is just a bit of added reinforcement.

Best,

Michael
Author:  Sam Price [ Sat Jun 17, 2006 9:48 am ]
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[QUOTE=Hesh1956] Hi Sam! I don't think that I have welcomed you to the OLF yet so here's a huge welcome to you![/QUOTE]

Thank you!!

[QUOTE]Do you have the Stew-Mac kit?[/QUOTE]

Good guess!! Yes, I have...

[QUOTE]Since your braces are preshaped this may be the case and it would be helpful to me to know.[/QUOTE]

Yes, they are preshaped...



[quote] A cap is highly recommended and if you want I would be happy to tell you how to make one.[/QUOTE]

Yes please, I would really appreciate it.

Author:  Colin S [ Sat Jun 17, 2006 8:34 pm ]
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Hey, I started with a SM kit as well, a mahogany sitka OM, since retopped with Euro, they are a great introduction to building and the recommended path for any new builder, plus as has been said they will produce an outstanding guitar. It's nice to have your first guitar sound good.

I'd certainly get some wood from Touchstone and carve a new X-brace, and put a cap on it. If you want some guidance on how to do that feel free to PM me.

Colin
Author:  Sam Price [ Sat Jun 17, 2006 8:43 pm ]
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Thank you all...

I MUCH prefer the bracing/capping technique that Hesh recommends and as a newbie (I will not call myself a luthier until I have built my first guitar!!), I now see very clearly that new braces are needed.

One criticism about the Stewmac braces; that they ARE preshaped!! That's a matter of preference, and getting hold of blanks won't break the bank (can't wait until tommorow morning to order stuff!! :D)

I am planning to customise the kit; I endeavour to buy my own rosette, binding and purfling material, as I detest the plastic binding supplied with the kit.

Nevertheless, I will NEVER criticise the quality of wood. It is wonderful...for example, there is no "bad" side to the rosewood back...I spent 20 minutes under artificial lighting, natural lighting, in a dark room, and I still could not decide the best side!!! In the end I tossed a coin...
Author:  Brock Poling [ Sat Jun 17, 2006 11:41 pm ]
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Not only is the x structural, it is a main conduit of energy into the top, if there is a disconnect here it will substantially hurt the sound of the guitar. I think you are right to make a new set of braces.

Capping is something you want to do, even with a perfect fit. Essentially when you notch the x brace you weaken the brace dramatically, the cap basically restores all the original strength.

BTW, this notch should be "squeeky" tight, but not so tight that it takes a hammer to get them together. A really tight press fit is perfect.

Good luck with the build.
Author:  Bill Greene [ Sat Jun 17, 2006 11:44 pm ]
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[QUOTE=Sam Price]

One criticism about the Stewmac braces; that they ARE preshaped!! That's a matter of preference, and getting hold of blanks won't break the bank (can't wait until tommorow morning to order stuff!! :D)

I am planning to customise the kit; I endeavour to buy my own rosette, binding and purfling material, as I detest the plastic binding supplied with the kit.

[/QUOTE]

Yep, that's what I did. I did not use SM's braces, their binding/endgraft, bridge plate, pins, nut/saddle, etc. I took the "buff" off of their bridge, but I used it. Cut a curved end of the fretboard vs. straight, and filled and re-drilled for different tuners, etc. In the end, it's possibly even best if you customize the kit...it's a reflection of your personality. Have fun, and make sure to post your progress.
Author:  crazymanmichael [ Sun Jun 18, 2006 12:08 pm ]
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i can only second the recommendation of those who say make new ones.

as to the cap, an engineering chap commented here or on one of the other fora to the effect that a cap has a dramatic effect on the strength of the brace. the top serves as the cap on the other one.

besides, it just plain looks better!!!
Author:  TonyKarol [ Sun Jun 18, 2006 10:53 pm ]
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Not sure how many of you had noticed, but the pix of the 66 MArtin in the other thread where Fedex ran over the box with a truck - the X is clearly visible in the top, and its still intact. Thats how important it is for it to be solid. Too bad it couldnt have saved the rest of the guitar.
Author:  Michael Dale Payne [ Mon Jun 19, 2006 12:33 am ]
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I did not see if this was the 000 or the dreadnaught kit. If the dreadnaught, they sell a top bracing kit in their standard product line. But even if it is a 000, I would just about guarantee they would sell you a replacement set. Heck they are probably the same x-brace just set at a different angle.

NO broken brace on a guitar should ever be glued up and used. the strength and its ability to efficiently transfer both load and energy has been compromised.
Author:  ms960 [ Mon Jun 19, 2006 2:44 am ]
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New here, and this post caught my attention. First, let me say that this forum has been very valuable in my guitar-building education.

I'm working on my first kit (Stew-Mac dread). My x-braces do not fit together snuggly, i.e., I didn't notch them very well and as such there are gaps on both sides where they cross. I guess I didn't know it would be an issue, but now it seems that it is. They are glued and attached to the top, and I was getting ready to attach the top to the sides within the next day or so. Should I make a cap, or fill the gaps with small pieces of spruce to eliminate them?

Thanks all.
Author:  Michael Dale Payne [ Mon Jun 19, 2006 3:00 am ]
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Yes make a cap. Yes tightly fit splices to fill the gaps. This is not the best solution on the gaps but will serfice. If you do not fill the gaps you will end up with a rattle. The proble with filling the gaps with splices is in srinkage and expansion of the joint. the right way to correct the problem is to carve off the braces and build new ones but filling the gaps with like wood and in the proper grain direction will get the job done.

Keep in mind when building that the braces do more than support the top. they also carry the energy imparted by the stings throuhout the top. Any break in their solidarity is a terminal node. meaning energy caried by that section of the brace will terminate ant the break or gap. So if there is a gap at your x connection there will be a loss in energy there.MichaelP38887.5016087963
Author:  ms960 [ Mon Jun 19, 2006 3:21 am ]
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Thanks for the assistance. Hope I can make some splices to fill the gaps snuggly. How seriously will this affect the tone of my guitar assuming I get the gaps filled reasonably tight, and make a cap?
Author:  Michael Dale Payne [ Mon Jun 19, 2006 3:28 am ]
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if you get them fill tight there should be little noticable loss in volume. It is hard to say just what the tonal affect will be but it will be acceptible. the expansion and contraction issue I think is long term worry so the splices need to fit good. Whike I don't like cloth overlays on xbrace joints you might consider that for long term stability of the patch.
Author:  Sam Price [ Mon Jun 19, 2006 6:54 am ]
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The answers here are amazing, thank you all. I have read and sometimes joined many forums, and this is the most informative and friendly I have been on.

I endeavour to create X bracing that is strong, light, and has a very good join. Starting from scratch will enable me to create 90 degree notches, as opposed to the "V" shaped notch for the stewmac preshaped...it's more like a narrow "U"...a very difficult thing to achieve well on my first try.

As they say, make the cuts smaller than the measurements, and file 'till it fits!!!
Author:  Michael Shaw [ Mon Jun 19, 2006 12:53 pm ]
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[QUOTE=TonyKarol] Not sure how many of you had noticed, but the pix of the 66 MArtin in the other thread where Fedex ran over the box with a truck - the X is clearly visible in the top, and its still intact. Thats how important it is for it to be solid. Too bad it couldnt have saved the rest of the guitar.[/QUOTE]
I myself feel that was just a fluke and doesn't prove anything. That was just a freak accident and shows nothing in relation to way a x-brace performs on a guitar. I would like to see how many times this would happen in more simialar accidents.
Author:  TonyKarol [ Mon Jun 19, 2006 11:11 pm ]
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Maybe so on the fluke part of it Michael, only the big guy knows for sure - but the strongest part of the top is the bridge/top/X brace/bridge plate area.
Author:  Michael Shaw [ Tue Jun 20, 2006 10:36 am ]
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Tony I don't dispute you there on that.
Author:  Michael Shaw [ Tue Jun 20, 2006 10:49 am ]
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To slightly change this discussion what's the opinion on scalloping and tapering top braces? In a GAL article on John D'Aquisto it stated he never used scaloping or tapered his top bracing. He built amazing sounding guitars even so. So what are you opinions on the purpose of scaloping and tapering. There were a lot of old guitars that were built without this technique and they still sounded great. What does it add?
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