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first top bracing, critique?
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Author:  gratay [ Sun Sep 09, 2007 4:36 pm ]
Post subject: 
Its a Cedar top OM size....and the top thickness is 0.125".....
My initial idea was to make the brace size around 10% bigger than what would be normal for spruce..
so x-brace and tone bars dimensions are 0.3" (7.6mm) x 0.52" (13.2mm); finger braces 0.3" x 0.43" (10.9mm);
upper brace is 0.555"(14mm) x 0.555"...as a starting point ...then I painstakingly have been carving everything with a chisel......wish I had a little plane but I don't ....
anyway I was wondering what people think of it so far as I'm not entirely sure of what I'm supposed to be hearing when I tap it.....other than i know it is ringing for a little longer and doesn't sound like a dead thud before i started carving....accept where the tone bars join up to the x-brace it still sounds like a thud to me in that area ?
the finger braces still have the same sort of profile as the antes plans i have.....Do they need to be this big?
I'm wondering also whether to inlet the bottom legs of the x-brace also...? and if the bracing is still on the heavy side? the centre point of the valleys on the scallops is around 0.34" ( 8.7mm )...
Overall is there anything glaringly obvious that I should be looking at?
thanks and be as critical as you want, please.
cheers Grant



Author:  KenH [ Sun Sep 09, 2007 5:03 pm ]
Post subject: 

You have a really good start. Personally, I dont like to see square corners on my bracing. I would sand these down until most everything is rounded over. You may also want to consider reducing some of the mass of the transverse brace also. It looks really wide from the pictures, but that may be because of the closeup picture.


 
Author:  bob_connor [ Sun Sep 09, 2007 5:35 pm ]
Post subject: 
G'day Grant

Get that chisel out and have more of a lash at it.

It looks too chunky and overbraced.

If you are concerned about chiselling into your top put a couple of layers of masking tape on either side of the brace while you are carving.

I'd be trying to make those braces tall and narrow so take the bevels almost down to the soundboard. (more a vee profile) And take a some more out of the scallops.

The finger braces look as though they could come down too.

I'm just about to do a cedar top the same thickness as yours with bracess at 6mm x 12mm and I'd be looking at having a lot less timber attached to the soundboard before I started listening for decent tap tones

Depends on your top but cedar is generally not as stiff across the grain as spruce so bear that in mind when taking down the finger braces. You could also change the angle of the x-brace to stiffen it up but it's too late for that on this one, but bear it in mind for the future. I can't really see the x-brace angle from your pics.

Bear in mind that Dave and I tend to make everything fairly light as far as bracing goes so I may be biased in that direction. But I think you could very safely take to this top with more severity to achieve a better result.

Throw some more pics up as you are progressing through it.

Cheers

Author:  Martin Turner [ Sun Sep 09, 2007 7:43 pm ]
Post subject: 
Grant,

Check out my recent bracing critique and then dont do everything I did and you should be right!
Author:  James Orr [ Mon Sep 10, 2007 4:17 am ]
Post subject: 
I was going to say to take more off, too, but I'm not sure since they're 1/
2" tall. That's why I haven't said anything. The shortest I've seen are .6".
I wouldn't want to make it too weak by taking more off, and I'm interested
in hearing from others about it.
Author:  tippie53 [ Mon Sep 10, 2007 3:14 pm ]
Post subject: 
I agree that you need to avoid sharp corners, These become force focus points . Also ad some reinforcement to the X brace joint. I personally use a gun cleaning wad
john hall
Blues creek gutiars
Author:  gratay [ Tue Sep 11, 2007 10:00 am ]
Post subject: 
Thanks very much guys
theres some good observations there....I hadn't thought into the sharp edges factor so much and from what you all have said i will be rounding everything.

I am definitely capping the X-brace . Just wanted to post pics and see if anyone saw anything in that region that needs work before i go ahead and cap it.

It is definitely loosened up around the outer rims especially at the end of the tone bar region....but around the bridge plate I'm gathering it may be hard to get as much resonance because of the mass?

Does anyone think the finger braces should just come to a triangular point at the centre of the brace? instead of a long flat brace.

Ken - the transverse brace is slightly larger than most although the pic does make it look quite large..
it started out 14mm x 14mm ...I guess most are maybe 12 -13mm....I can probably take the height down a bit or round the top more or both?

Bob - I will have a lash at it ...and as far as the angle of the x...it is actually a tiny bit wider by maybe 1 or 2 degrees because of the fact it slipped a bit when i was gluing up and I couldn't see the pencil marks because of the squeeze out....don't know what this means as far as sound or stiffness .
I really appreciate you guys taking the time to comment on it...thanks a lot.
Author:  phil c-e [ Wed Sep 12, 2007 9:06 am ]
Post subject: 
grant,

i'm with hesh on cutting the top to your profile plus a bit extra.

i'm just about finished my second cedar topped guitar and have tried to correct the problem i had on my first cedar build. along your line of thinking about how this species is weaker, i made the mistake of overbracing. i used my standard 6mm brace, but went 2mm higher at the x (from 14 to 16) and ended up with a guitar that sounds very 'middy' to my ear. not enough bass and very little of the warmth that cedar is known for.

my guess is that most builders use very similar bracing on spruce and cedar topped guitars and then just live wtih the fact that a cedar top will be more fragile and have lower headroom than a spruce top. just my hunch though. maybe those with way more experience want to confirm or correct.

phil
Author:  gratay [ Wed Sep 12, 2007 2:36 pm ]
Post subject: 
Thanks Hesh, Todd and Phil,

I certainly have a clearer picture in my head now of what I should be shooting for..
and I will probably look at more of a triangular shape as Hesh pointed out.
The closeup does make the transverse brace look huge...
its just over 1/2" square but I can probably go for less mass for this one also i guess.
I will post some pics of the progress and see what the verdict is..
thanks again everyone.
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