Official Luthiers Forum!
http://www.luthiersforum.com/forum/

top bracing critique
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21467		 Page 1 of 1
Author:  J Hewitt [ Sat Mar 14, 2009 6:54 pm ]
Post subject:  top bracing critique
Hi,
I know others have posted the same thing......hope ya'll dont mind another. I find it interesting and educational all the different opinions about top bracing.

This is a small body 13-1/2 lower bout....10 upper bout. My top thickness is .110

This is my 5th guitar and I would like to have some feedback on what I have done so far with my bracing. I believe the last guitars are over braced somewhat and would like to start doing a little better in that area....
My X-brace is .5 in height at the X
Tone bar is about .375 in height at hightest point.
Finger braces about 3/16 in height.

I dont know anything about the tap tuning process. Only what I have read here in the archives. If you notice the photo with the black spot at left hand side of picture....that is were I held the top. I've tried a couple of other spots but this one is were the ring sounds the clearest and loudest. At this point there is a nice ring when taped at various points on the top, especially on the treble side.

I'm not sure if I should stop or keep going a little more.

I certainly would appreciate any feedback!

I have ordered John Mayes "Advanced voicing" DVD but might be awhile before I get it.

Thanks,
Jeff
Author:  Burton LeGeyt [ Sat Mar 14, 2009 7:22 pm ]
Post subject:  Re: top bracing critique
Hi Jeff,

The things that I notice right off are that your x angle is not very wide and your tone bar is at about a 45 or so. Usually if I am using less than 90 on the x brace angle I figure there is quite a bit of long grain added stiffness and I run the tone bar more across the grain. If you have a well quartered piece of spruce with good cross grain stiffness opening up the x will help it sound more open in my experience. Assuming also the spruce is stiff and since the guitar is pretty small I would thin the top some more. The upper bout is fine at .11 but I would be below .1 below the bridge and even a little thinner toward the edges. I think you could safely go down closer to 5/16 or so on the tone bar and I would taper the bridge plate at the back(make sure the tapering starts behind where the pins will anchor). Less mass in that area can help a lot.

Please take this with a grain of salt of course but that is what I notice. The work looks really impressive and clean.
Author:  J Hewitt [ Sat Mar 14, 2009 9:13 pm ]
Post subject:  Re: top bracing critique
Thanks Burton,
The angle on the X is about 84 deg..... The first one I built like this the X was about 92 deg.... and I scalloped this braces. Maybe I should have stuck with that X brace layout?

The top is'nt all that stiff. I left it at .110 and figured once the box is glued up and I do final sanding it will be somewhat thinner...

Thanks for your help and critique!

Jeff
Author:  Burton LeGeyt [ Sun Mar 15, 2009 12:22 am ]
Post subject:  Re: top bracing critique
No problem Jeff!

I read through my post again and I realized I wrote cross grain where I should have written long grain. It should have read if the long grain stiffness is good (or high in relation to the cross grain stiffness) I open up the x brace. I just wanted to clarify that.
Author:  J Hewitt [ Sun Mar 15, 2009 10:46 am ]
Post subject:  Re: top bracing critique
Well....126 veiwers and only one person to give there input.....

How should I take that?? Is there not enough info to go on?

Jeff
Author:  woody b [ Sun Mar 15, 2009 11:21 am ]
Post subject:  Re: top bracing critique
The bridgeplate looks big to me, but it might just be the picture or my perception. I keep my bridge plates between 1 1/4" and 1 1/2" depending on the guitar. I also like for my X-brace to be spaced wider at the ends(more angle). It could just be that way the picture looks though. What angle is the X-brace. It looks like it's 90 degrees or less. I use anything from 98 degrees (like every Martin I've measured) to 105 degrees (like a Gibson Advanced Jumbo). Larrivee's use a 90 degree X Brace but their tone bars are at a right angle to the centerline of the top. The taper on the braces looks good. .110 is probably waaay thick for the top but I thickness tops by feel instead of measurements. I also graduate my tops. My tops usually end up .010 to .015 thinner around the edges than they are in the middle. I can't tell much about the width and height of the braces.

Disclaimer: I'm not an expert, and I'm not pretending to be. I've just giving my opinion since you asked.
Author:  SimonF [ Sun Mar 15, 2009 11:31 am ]
Post subject:  Re: top bracing critique
Hi Jeff,
I would likely get those x-braces thinner if at all possible. My bracing system is a bit different than most. I use a brace behind the bridge plate and that changes the amount of bracing needed to temper lower bout bellying. Having never done the normal lower bout tonebar layout, I can't tell you whether that one brace is more or less sufficient than you need.

Structurally, the way I approach bracing (regardless of the pattern being used) is to make the complete top as light as possible but still very strong in the critical areas.

To give you an idea of how thin I make my bracing, here is a picture from my website.

Image
Author:  charliewood [ Sun Mar 15, 2009 12:56 pm ]
Post subject:  Re: top bracing critique
I cant comment on your bracing as Im working on my first 2 guitars myself - its nice and clean.... that I can say -
What I can comment on is this comment
Quote:
Well....126 veiwers and only one person to give there input.....

How should I take that?? Is there not enough info to go on?

Jeff


There is alot of non participant traffic on the OLF - and more lurkers,,,, who just dont comment period.... There is also the fact that weekend traffic is a slow time to recieve posts from the regular forum members,,, they tend to be off doing things... and the discussion traffic picks back up during the week,,
Sometimes the first poster sums up the thoughts of many other would be posters and they feel the need to echo the sentiments...
So dont feel any way about that bud... youll get some responses - but be patient
Cheers
Charlie
Author:  Howard Klepper [ Sun Mar 15, 2009 1:02 pm ]
Post subject:  Re: top bracing critique
Your bracing looks pretty good; not oversized to my eye. I taper the lower face diagonal down to the top where it meets the X, and I do not find a lot of sense in so-called "parabolic" (i.e., convex) bracing. But others say they are pleased with their results. Part of the problem in commenting is that people work out systems that work for them, and it isn't just one thing or another that changes; it all works together.

One thing I say regularly, although I have no idea if anyone is listening: The first fixed point in laying out a brace design is bridge location. The second is where you want the arms of the X to cross the bridge wings. Then you have a range for opening or closing the X depending on where you anchor the arms in the upper bout. Do not start with an angle, or a distance from the soundhole to the X, or from the bridge to the X, or "forward" X or the like; these are artifacts of your other choices.

At least that's how I do it. Others may get good results approaching the issues differently. My overriding advice is to have the system make sense to you; if you are designing a bracing system, as opposed to following a plan, don't do anything you for which you don't see the purpose.
Author:  Lillian F-W [ Sun Mar 15, 2009 1:09 pm ]
Post subject:  Re: top bracing critique
J Hewitt wrote:
Well....126 veiwers and only one person to give there input.....

How should I take that?? Is there not enough info to go on?

Jeff



Not necessarily Jeff. I for one am sitting on the sidelines waiting for experience to weigh in and see what gets said.
Author:  Bruce Dickey [ Sun Mar 15, 2009 6:24 pm ]
Post subject:  Re: top bracing critique
I like it a lot for a small body guitar. I'd be tempted to put a second tone bar in there, but the reason I think you can rightfully leave it out is that you put the requisite cleats in on the seam.

Take careful measurements and notes and let 'er rip. I think you have a winner. Beats the heck out of ladder-bracing of years past me thinks.

Congratulations on a nice job.
Author:  Dave Rickard [ Sun Mar 15, 2009 7:33 pm ]
Post subject:  Re: top bracing critique
Howard Klepper wrote:
One thing I say regularly, although I have no idea if anyone is listening:

Trust me Howard, when you talk I perk up on the edge of my seat and pay attention.
Your answers are always concise and easy to read.
THANKS
Author:  Rod True [ Sun Mar 15, 2009 7:49 pm ]
Post subject:  Re: top bracing critique
Howard Klepper wrote:
...
One thing I say regularly, although I have no idea if anyone is listening: The first fixed point in laying out a brace design is bridge location. The second is where you want the arms of the X to cross the bridge wings. Then you have a range for opening or closing the X depending on where you anchor the arms in the upper bout. Do not start with an angle, or a distance from the soundhole to the X, or from the bridge to the X, or "forward" X or the like; these are artifacts of your other choices.

At least that's how I do it...


That's the way I do it too. Locate the bridge, place the X in relation to the wings and everything else follows from there. [:Y:]
Author:  crich [ Mon Mar 16, 2009 11:10 am ]
Post subject:  Re: top bracing critique
The reason for the low response is that the bracing looks fine. Eat Drink Might want to thin around the perimeter a tad after scraping binding. Clinton
Author:  gozierdt [ Mon Mar 16, 2009 8:53 pm ]
Post subject:  Re: top bracing critique
Jeff,

I think the bracing looks pretty good, I wouldn't make any changes. I just finished two smaller bodied
guitars with similar dimensions to yours, and I took the tops down to about .095"-.100", and so far both
are doing well, but I certainly wouldn't take them any thinner. I'd leave your top just as it is, and string
the guitar up before finishing, if you want to experiment with a thinner top...

I also agree with several of the posters above that the X-brace angle looks smaller than I usually use. It's
unusual for the top of the X-brace to come so close to the UTB. I wouldn't change it on this guitar, see
how it sounds.
Author:  David R White [ Mon Mar 16, 2009 8:56 pm ]
Post subject:  Re: top bracing critique
IMHO .11 inches for a guitar with a 13.5" lower bout is considerably thicker than most would build with - even if it's not stiff.
Author:  Dave Anderson [ Mon Mar 16, 2009 10:13 pm ]
Post subject:  Re: top bracing critique
Dave Rickard wrote:
Howard Klepper wrote:
One thing I say regularly, although I have no idea if anyone is listening:

Trust me Howard, when you talk I perk up on the edge of my seat and pay attention.
Your answers are always concise and easy to read.
THANKS

Yes, I'll second what Dave R. said....When Howard speaks, We listen!
On your bracing- I think it does look good as long as your bridge wings are over the
lower X braces.
Author:  Colin S [ Tue Mar 17, 2009 5:22 am ]
Post subject:  Re: top bracing critique
Golden rule of the OLF, always listen to Howard's advice.

As to your bracing, looks fine to me as well, though without the top in hand it's always impossible to give reliable advice on these top bracing questions.

Colin
Author:  Terence Kennedy [ Tue Mar 17, 2009 6:21 am ]
Post subject:  Re: top bracing critique
I think it looks fine as well. If it sounds a little tight after closing the box you can always thin the edges of the top a bit in the lower bout before binding.
Terry
Author:  J Hewitt [ Wed Mar 18, 2009 3:44 pm ]
Post subject:  Re: top bracing critique
Thank you for all who commented!
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/