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bracing critique part II
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=13784		 Page 1 of 1
Author:  gratay [ Tue Sep 25, 2007 9:33 pm ]
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Ok as per all the excellent advice i have received kindly from the wise folks here i have kept on ploughing away at my top and got to this stage.

I have made the bracing a lot more triangular and gone a bit deeper into the middle of the scallops. Also bracing is not sharp but sanded a bit rounder..
I tapered done the top legs of the X -brace a bit .

Not to sure whether to taper down some more...and maybe make the finger braces smaller. ( It is a cedar face)?
but its definitely sounding better than before.
Not sure how far to go ?
What do you guys think..and thank you for the guidence so far.. It has been very helpful






cheers Grant
Author:  gratay [ Tue Sep 25, 2007 9:38 pm ]
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I forgot to add ..
I'm still undecided whether to tuck the bottom legs of the x-brace ..I did read someone mentioning that you should always tuck with a cedar face because the glue bond is not as strong as with a spruce face?
I don't know if this is true ?
cheers grant
Author:  JJ Donohue [ Tue Sep 25, 2007 10:05 pm ]
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Grant...This looks quite clean and neat. Depending on the stiffness of the top it may still be a bit heavy on the bracing to my eye.

What happens when you suspend the top from the sides and push in at the bridge plate area? Can you see slight movement? If the lower bout moves with moderate force, you're close. If not then scallop the lower x-brace legs a bit more.

How does it tap then? Start to remove material from the tone bars and finger braces until you hear a pleasant sound all around the lower bout area.

At this point, it would be a great idea to refer to John Mayes' Voicing DVD's...they helped me tremendously.

At some point soon...even without a lot more material removal, once you hear a pleasant tone, you should just stop and glue it all together. Take copious notes and use this experience as a basis of comparison to determine how you'll voice the next guitar. Good luck!
Author:  jeffhigh [ Tue Sep 25, 2007 11:30 pm ]
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A couple of comments from an engineering point of view only, (I have no experience with bracing yet)


The cap over the Xbrace lap is a bit small in thickness and does not have much overlap onto the bars.


The brace above the soundhole is quite massive but the trussrod access hole has left very little material on the outer face.


As I said, structural comments only no comments re tone.
Author:  phil c-e [ Wed Sep 26, 2007 8:44 am ]
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grant,
based on the seven that i've built it looks to me like your in the ball park, but probably on the heavy side of the park. looks like the braces are wider than the 1/4" (or 6mm) that is often used by hand builders. my x and tonebar profiles look a lot like yours, but 6mm. the finger braces could probably stand to loose some beef.
what i did on my first build (also an OM) was spend time looking at the top bracing pics on frank fords 'frets' web site. i stared for a long time at the picture of the santa cruz om bracing and tried as best i could to imitate it. check it out. it's worth it. i think it's also worth remembering that most first time builders will err on the side of leaving too much bracing.
but like i said, you're definitely in the ball park. you're going to love your guitar.
phil
Author:  John How [ Wed Sep 26, 2007 10:11 am ]
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Looking good Grant but as others have said you could safely remove a little more height and still be safe and the finger braces are definately on the beefy side. It'll no doubt make a fine guitar if you finished it as is but I think I'd take a bit off all the braces in the lower bout, The peaks don't need to be too high either. The upper looks good to me. Tucking those lower X legs is a bit more work and I don't bother, I just treat'm like you did your other tone bars. Nice work too by the way, it looks real good and will make a wonderfull guitar.
Author:  Philip Perdue [ Wed Sep 26, 2007 6:00 pm ]
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Grant,

Bravo for showing your work and requesting a review of your work. Your work looks pretty clean. I am about to close my first box but would never show my bracing. Mine looks ok but is not going to be over braced. The problem with mine is that it looks like a 5 year old attacked it with an ax and had little skill to work with at that. Your work looks pretty good. The people on the OLF have a lot of knowledge and it looks like you are taking their comment as given in the spirit of positive sharing and not as a negative. All I know is that in the couple of years I have lurked or participated at this site everyone, I think to a man or woman, has said that their first or first few were overbuilt. In fact, I'm not sure if I have ever heard someone say they underbuilt one. I have been trying to avoid over building my soundboard but the lutz in really really stiff and I keep working on it a bit at a time. John Mayes DVD on tap tuning is pretty good and I too would recommend it.

Someone once told me that if it looks like a guitar and is built like a guitar then it will sound like a guitar. This has alway helped me because I figure it means if you pay some attentio to your work it will turn out fine.

Sheesh, a bit off my face here. Guess I shouldn't be posting now

Its looking good so take your time and enjoy the process. It will be fine and you will alway have a smile on your face when people say "wow, Its a bonzer ..you built it yourself".

So no worries grab a slab and relax.

PHilip
Author:  gratay [ Wed Sep 26, 2007 8:25 pm ]
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cheers guys ,...thanks for the help so far
JJ,..i tried the pushing at the bridgeplate area and it does flex ever so slightly and thats with a fair amount of pressure ..I guess once its glued to the rims it will be a lot stiffer.
as far as tap tone its a low note all around the lower bout and rings for a fair amount of time. Except in the area around the x where the tone and finger brace meets the x..I guess there is a lot of mass around that area but i took some more out of the x scallop today.

Todd ,..I read and read and decided to not tuck and have feathered the bottom legs out today

jeffhigh, i wasn't exactly sure how long the cap should be so i had a bit of a guess

phil, yeah your right the braces are slightly wider than 6mm..they are between 7-7.5mm wide. and i did a bit more work on the finger braces today ...I will have a look at frank fords site for what you are talking about

john how , the concensus so far has been the beefy finger braces here and other forums i frequent so I will need to look at that and the height that you mention, thank you

and phillip,
yes I like the spirit of sharing. I can learn something and more importantly by posting these things hopefully it will help someone in their research down the track..
and you also remind me that john mayes voicing dvd wouldn't go astray...I will have to get that someday.

thanks to all
Author:  Michael Dale Payne [ Thu Sep 27, 2007 2:55 am ]
Post subject: 
Unless I just missed it no one mentioned the shape of the x brace in the bridge plate area. I will shape my x-brace to a parabolic or triangular shape from 1" in front of and behind the x intersection. I do this before I scallop the brace. you is pretty much rectangular in shape for a good 6" behind the x intersection. That is a good bit of mass that you could get rid off.

Like the other have said the upper transverse brace is too beefy as are your finger braces.

That said truth is most all of us over braced our first several guitars.
Author:  PDeWitt [ Thu Sep 27, 2007 12:07 pm ]
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[QUOTE=MichaelP] I will shape my x-brace to a parabolic or triangular
shape from 1" in front of and behind the x intersection. I do this before I
scallop the brace. you is pretty much rectangular in shape for a good 6"
behind the x intersection. That is a good bit of mass that you could get
rid off.
[/QUOTE]


Michael,
I was reading this thread and found your insight here helpful. Clarifying
question:

Over what length of the x-brace do you make a parabolic cross-sectional
shape for the braces?

Thanks!
Author:  gratay [ Thu Sep 27, 2007 9:11 pm ]
Post subject: 
[QUOTE=MichaelP] Unless I just missed it no one mentioned the shape of the x brace in the bridge plate area. I will shape my x-brace to a parabolic or triangular shape from 1" in front of and behind the x intersection. I do this before I scallop the brace. you is pretty much rectangular in shape for a good 6" behind the x intersection. That is a good bit of mass that you could get rid off.

Like the other have said the upper transverse brace is too beefy as are your finger braces.

That said truth is most all of us over braced our first several guitars.[/QUOTE]
thanks michael, I was wondering about the mass in this area.. because its definitely not as lively when you tap around there..I wish i had done some work on the x - brace before gluing the others on ...its not to late but it would have been easier.
cheers I will endeavour to lighten it up some more.
Author:  Michael Dale Payne [ Fri Sep 28, 2007 12:23 am ]
Post subject: 
I actually said that in what I posted. I shape the full length of the X-braces except about 1"-1 1/2" either side of the intersection joint.

What I did not say was, this leaves me plenty of room for a full width cap about 2 1/4" long . Once the cap is glued up and cured I go back and blend the shape up to the outer edges of the intersection and across the cap. this leaves me with little to no sharp edges prior to scalloping. After tuning the plates I take 22 sandpaper an lightly remove all sharp edges left by the scallops. I don't round over the scallops I just knot the sharp edges off the sides.
Author:  Michael Dale Payne [ Fri Sep 28, 2007 1:49 am ]
Post subject: 
220 sand paper
Author:  Michael Dale Payne [ Fri Sep 28, 2007 5:25 am ]
Post subject: 
This is an OM or OOO body I believe. Your X-brace appears to be at least 3/8" thick if not more. An OM does not need that thick of an X brace. On OMs I use to make mine 5/16 (.313") now days I make mine 7mm (.276") my tone bars are 1/4" (.250") and my Upper transverse brace on an OM is 3/8"(.375") on less the tops cross gran is less than desired. My fingers brace now days are 7/32" or 5.5mm (.219") on an OM.
Author:  Steve Walden [ Fri Sep 28, 2007 5:41 am ]
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Hesh and Micheal,  That is the most easily understood explanation of voicing I have seen to date.  Thank you.
Author:  gratay [ Fri Sep 28, 2007 3:51 pm ]
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First off, thanks hesh , michaelP and everyone else for giving me a very clear understanding of what the objective is....don't know how you guys can put it to words to make me understand , but you have... which made me realise that I wasn't finished yet..

and boy am I glad I kept plugging away at it because its really starting to sound nice now ..i also have a better understanding of what it should sound like having tapped it to death over the last couple days.


Progress report:-
first off I made the scallops a bit deeper then carved the x-brace and tone bars to more of a triangular shape to get rid of a fair bit of mass...this has helped immensly.
I also lowered the finger braces 1mm and shortened the length by 3mm where they join the x to try and free up some mass there..i also made them a bit more triangular.
I took a bit more of the squareness out of the transverse brace.

I still may do some work on the finger braces and maybe replace the cap with a longer one .
but overall I am really pleased with the way its going
thanks everyone.







Author:  Bruce Dickey [ Sat Sep 29, 2007 1:31 am ]
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Gratay,
What is the thickness of your soundboard?

Just wondering....
Author:  TonyKarol [ Sat Sep 29, 2007 2:13 am ]
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The latest AG has an ad in it for Huss anbd Dalton - there is a great picture of how they shape/scallop their bracing in that ad... just an FYI. FWIW, I think you fingers are still way too big - mine have no peaks at all, they are like a Larrivee, 1/4 wide and 1/8 tall, flat, and then tapered at the end to nothing, untucked. They are more for cross grain support than anything else. See the HD ad for the peaked ones shape.
Author:  gratay [ Sat Sep 29, 2007 9:41 am ]
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cheers Tony ,I will have a look at that add ...and do a bit more research into finger braces.

Bruce , the soundboard thickness is 0.125" (3.15mm).
it didn't feel particularly stiff so thats why I stopped there when i was thicknessing.
It may be on the thick side ..I'm not sure

thanks guys
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