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  #151  
Old 02-28-2014, 10:48 AM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by Viking View Post
Interesting. Who advised you not to radius the transverse brace?
I've built that way for more than 30 years. I was advised to do it that way by Charles Fox, but there are others who also do so.

Mr. Gore's latest books suggest reducing the radius on the transverse brace, to less than the curvature of the dish. This reduces the amount, he suggests, that the top needs to be thinned to be flat in the area of the fingerboard extension, if using a radiused transverse brace.

To turn the question around, who advised you to radius the transverse brace? (Most likely, it became popular when people started using radiused dishes/forms.)
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  #152  
Old 02-28-2014, 03:44 PM
Neil K Walk Neil K Walk is offline
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I was told by Tim McKnight. He told me that's how Ervin Somogyi does it too. BTW, I was also told not to taper the ends of the UTB and instead have the ends butt up against the interior of the sides to reinforce the upper bout.
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  #153  
Old 02-28-2014, 04:07 PM
LouieAtienza LouieAtienza is offline
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Ervin Somogyi does it that way because he builds the tops on a solera, which has a domed lower bout. But if you look at the picture of the soloera in his book, his solera is domed at the area of the upper transverse brace.

Really, I think it's much ado about nothing, unless you must have a zero neck set angle. You're talking about a strip of flat spot 2-1/4" or so in width in the upper bout; if you sand it [the area below the fretboard] flat, and used a 25' radius dish you are removing .002"(!) on what is largely considered and inactive part of the soundboard (unless you are in the cantilevered neck boat, in which case that area wouldn't be sanded flat anyway.) Plus, if you build in a neck block extension like Somogyi this difference becomes even more moot. I believe Taylor uses a 50' or 60' radius for their tops. I build my tops on a dead flat workboard. I am working on a "hybrid" top of sorts, but won't comment more on it untill I have a working prototype...
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  #154  
Old 02-28-2014, 08:13 PM
Viking Viking is offline
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Goodness, all kinds of thoughts on this subject.

Quote:
Originally Posted by charles Tauber View Post
To turn the question around, who advised you to radius the transverse brace? (Most likely, it became popular when people started using radiused dishes/forms.)
Nobody told me to radius the transverse brace. I guess I simply assumed that given the fact that every other brace on the guitar is radiused for a guitar with a radiused top, that one would be too. Though I had wondered how you glue the fretboard to it if it isn't totally flat. Here's the answer then. Either don't radius that brace or sand that area flat.

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Originally Posted by kwakatak View Post
BTW, I was also told not to taper the ends of the UTB and instead have the ends butt up against the interior of the sides to reinforce the upper bout.
Yes, that's something that Somogyi does as well, if I recall what I read from his book correctly. Partly to help prevent the need for neck resets. Helps resist the downward sinking of the fretboard into the soundhole and changing of the neck angle by the tension of the strings. If the modern acoustic guitar writes off the upper bout in terms of sound production, then that brace's purpose is 100% structural, and there is then no point to tapering it into the kerfing. Butt it into the sides and make it a strong joint.
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  #155  
Old 02-28-2014, 09:13 PM
LouieAtienza LouieAtienza is offline
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Quote:
Nobody told me to radius the transverse brace. I guess I simply assumed that given the fact that every other brace on the guitar is radiused for a guitar with a radiused top, that one would be too. Though I had wondered how you glue the fretboard to it if it isn't totally flat. Here's the answer then. Either don't radius that brace or sand that area flat.
Like I mentioned, the amount of wood removed to make the fretboard area is so small, the wood probably expands and contracts more than the "chord height" at the fretboard area. So either way I wouldn't sweat it too much. If you build a totally flat top then it doesn't matter at all. Where it does matter is when the neck is set. If you make the transverse brace absolutely flat, and you have a dome in the lower bout, that may make the action too high, and after a few days of settling, the action will be higher. And vice versa - if you have too much a dome it may require too tall a bridge/saddle for acceptable action, and that may torque the top too much - or, you have to taper the fretboard, but that may not look "right" visually. Whichever way you go, it will affect everything else after, so a "section" drawing to scale may be needed.

Quote:
Yes, that's something that Somogyi does as well, if I recall what I read from his book correctly. Partly to help prevent the need for neck resets. Helps resist the downward sinking of the fretboard into the soundhole and changing of the neck angle by the tension of the strings. If the modern acoustic guitar writes off the upper bout in terms of sound production, then that brace's purpose is 100% structural, and there is then no point to tapering it into the kerfing. Butt it into the sides and make it a strong joint.
A butt joint is probably the weakest joint you can have since you are glueing end-grain. Then you have a worse situation, since the only thing holding that transverse brace in is the top itself. If it were me, I'd add ribs right below the transverse brace, which would truly support it. What I do now is just notch the transverse brace into the lining, but I taper it only to half the lining height. I also laminate rosewood in the transverse brace to stiffen it up more. I'm in the process of a build now; when I have time I'll post some pics.

In my observations, the back plays just as much a role; as the "dome" of the back flattens, the neck pulls up. Spanish guitars have a "foot" at the bottom of the neck block which supports the neck. Guys like Traugott have a longitudal brace tying the back braces together in an attempt to retain the "dome" shape. I found laminating my back reinforcement strip, which is cross-grained, with a strip of the same back wood, in the same direction as the back wood, helps retain the dome nicely. I also moved the upper bout brace in the back more toward the neck block in order to reinforce the dome shape there.
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  #156  
Old 05-27-2015, 10:17 PM
Viking Viking is offline
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Life and some serious health problems conspired against me. But I am determined to finish at least 1 guitar! lol

So. Onward.

I still have all the stuff, and the components I already built. So I'm just picking up where I left off. I've been working for the last couple weeks, getting ready to brace the top.

Thicknessing the x braces.


Cutting the lap joint. This wasn't too hard.


Thicknessing the bridge plate.


Gluing the bridge plate.


I used my jointing plane to cut the radius into the braces. I used cumpiano's wooden dowel method to draw the initial radiused line into a piece of cardboard. Then I used the cardboard to draw the line onto the thicknessed brace. Then I used the plane below to plane down to the line. It's a bit tricky, but I think it worked fine. I'd be interested in hearing other ways of doing this, as this seems a bit hazardous to my fingers. Wouldn't be that hard to cut a finger tip off doing it this way.


Gluing the first x brace.


Gluing the other x brace.


Gluing the upper transverse brace.


Fashioning the lower "tone bars". I'm not going with the old Martin way of doing things, making the tone bars cross the lower face of the sound board.


The tone bar fit into place.


Another shot of the tone bar. On larger sized guitars, I'll do 3 of these (possibly). For this OO size, just 2. They are a quarter inch tall and a quarter inch wide. They will be shaped to a triangular shape.


Shaping the braces with my hock chisel. I love that chisel. Thing of beauty.


Closeup of one of the fan braces. Not the prettiest thing, but then, I've never done this before. I'm just glad I haven't yet put the chisel through the sound board. lol. Or my hand.


Here is the top with half the shaping done on the braces. Cutting the triangular shape is next. That'll be the hardest part. And after I'm done there, I'll glue the tone bars into place and shape them. The x braces are cut to 1/8 inch at the sides on the lower side, and 3/16 inch on the upper side. Should I go lower than that? Any thoughts there?


For the upper transverse brace, I'm going to leave the majority of the material alone, and cut a steep angle where the brace meets the side/kerfing. I'll then fashion a rib with a complimentary angle to provide a strong, load bearing anchor point to glue the transverse brace to.

I also had already put the x brace patch in place, a small piece of sitka. But I realized after that I probably shouldn't have put it there yet, it gets in the way while shaping the braces. So I planed it off. I'll put it back on when I'm done.
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Last edited by Viking; 05-27-2015 at 10:23 PM.
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  #157  
Old 05-27-2015, 10:22 PM
Viking Viking is offline
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Prior to cutting away all this material, the soundboard didn't have much in the way of a tap tone. But now, goodness. I can hear several different notes in there. And that's saying something given that I'm half deaf. Hearing that many notes is good, right?
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  #158  
Old 05-28-2015, 04:24 AM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by Viking View Post
I'd be interested in hearing other ways of doing this, as this seems a bit hazardous to my fingers.
There are many ways to shape the arch into the braces.

One way is to make up a jig for use with either a disk or belt sander. Clamp the stack of braces to the jig, which has the desired curvature profile on the front of it, and present the curved profile to a long stop in front of the disk or belt. The braces overhand the stop to touch the sanding disk/belt. Then just sand until no more sands off and you have the perfect curvature. Works well, takes 2 minutes.

Another way is to create a jig to use with a router and template bit. Downside is that it can tear the wood, or go at it from the center outwards.

Another way is for those that use arched dishes, just run the brace back and forth on the sandpaper-covered surface of the dish.

Another way is to arch the braces one at a time, placing them in a vice and using a block plane to get the curvature close to a drawn line, then finish off on sandpaper.

Another way that I use these days is to make a fixture that clamps several braces at once. It is exactly sized to fit the width of my block plane. The edges of the bottom of the block plane, to the sides of the blade, ride on a curved surface that is the exact curvature I want. Run the block plane back and forth. When it stops cutting, the braces are ready to glue. Takes about 2 minutes, perfect every time.

One I haven't tried, but would probably work, is to setup a shooting board that has the desired curvature in it for the plane to follow. That would be quick and easy, once the setup is created.

Of course, these days, there is also the possibility of using a CNC machine. Unless I'm doing a lot of them, I can probably do it faster with my block plane fixture.

I'm sure there are other methods, limited only by one's ingenuity.
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  #159  
Old 05-28-2015, 06:41 AM
Ned Milburn Ned Milburn is offline
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Looking good, Viking!

I am curious... Are you using a different bracing pattern than the plans you have? Why do you have a "hollow" cut out above where one brace will fit to the bridgeplate?

I am not at all against "bridges" or hollows in bracing, in fact I use the concept myself, but I can't understand the function from your photos.
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  #160  
Old 05-28-2015, 11:15 AM
Viking Viking is offline
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Quote:
Originally Posted by charles Tauber View Post
There are many ways to shape the arch into the braces.

One way is to make up a jig for use with either a disk or belt sander. Clamp the stack of braces to the jig, which has the desired curvature profile on the front of it, and present the curved profile to a long stop in front of the disk or belt. The braces overhand the stop to touch the sanding disk/belt. Then just sand until no more sands off and you have the perfect curvature. Works well, takes 2 minutes.

Another way is to create a jig to use with a router and template bit. Downside is that it can tear the wood, or go at it from the center outwards.

Another way is for those that use arched dishes, just run the brace back and forth on the sandpaper-covered surface of the dish.

Another way is to arch the braces one at a time, placing them in a vice and using a block plane to get the curvature close to a drawn line, then finish off on sandpaper.

Another way that I use these days is to make a fixture that clamps several braces at once. It is exactly sized to fit the width of my block plane. The edges of the bottom of the block plane, to the sides of the blade, ride on a curved surface that is the exact curvature I want. Run the block plane back and forth. When it stops cutting, the braces are ready to glue. Takes about 2 minutes, perfect every time.

One I haven't tried, but would probably work, is to setup a shooting board that has the desired curvature in it for the plane to follow. That would be quick and easy, once the setup is created.

Of course, these days, there is also the possibility of using a CNC machine. Unless I'm doing a lot of them, I can probably do it faster with my block plane fixture.

I'm sure there are other methods, limited only by one's ingenuity.
Thanks Charles. Lots of ideas. I don't suppose you have a picture of the 2 minute fixture you use with a block plane?

Quote:
Originally Posted by Ned Milburn View Post
Looking good, Viking!

I am curious... Are you using a different bracing pattern than the plans you have? Why do you have a "hollow" cut out above where one brace will fit to the bridgeplate?

I am not at all against "bridges" or hollows in bracing, in fact I use the concept myself, but I can't understand the function from your photos.
Yeah, I meant to mention something about that but forgot. Yes, the lower braces are different than the plan I have. The thought behind those is something I read about here...

http://www.edwinsonguitar.com/Design...nd_Tuning.html

My intent is to limit the amount of wood and mass the bracing has, while providing sufficient structure to resist the upward pull of the strings on the back of the bridge/bridge plate. Having the lower face braces contact the bridge plate seems to me to be the way to do that.

But I should have measured the string spacing on the bridge plate more carefully. The flying part of the brace was intended to give sufficient clearance for the bridge pins, but the way the spacing worked out here, they aren't needed. There is plenty of space on the bridge plate for the bridge pins even if the lower face braces hadn't arched over the bulk of the bridge plate. So in the future, I would make these smaller size guitars without the arch, larger guitars with an arch on the middle brace.
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Last edited by Viking; 05-28-2015 at 11:25 AM.
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  #161  
Old 05-28-2015, 11:25 AM
Ned Milburn Ned Milburn is offline
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Quote:
Originally Posted by Viking View Post
Thanks Charles. Lots of ideas. I don't suppose you have a picture of the 2 minute fixture you use with a block plane?


Yeah, I meant to mention something about that but forgot. Yes, the lower braces are different than the plan I have. The thought behind those is something I read about here...

http://www.edwinsonguitar.com/Design...nd_Tuning.html

My intent is to limit the amount of wood and mass the bracing has, while providing sufficient structure to resist the upward pull of the strings on the back of the bridge/bridge plate. Having the lower face braces contact the bridge seems to me to be the way to do that.

But I should have measured the string spacing on the bridge plate more carefully. The flying part of the brace was intended to give sufficient clearance for the bridge pins, but the way the spacing worked out here, they aren't needed. There is plenty of space on the bridge plate for the bridge pins even if the lower face braces hadn't arched over the bulk of the bridge plate. So in the future, I would make these smaller size guitars without the arch, larger guitars with an arch on the middle brace.
Interesting. Basically a Spanish fan brace pattern blended into the main X.
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  #162  
Old 05-28-2015, 11:36 AM
Viking Viking is offline
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Quote:
Originally Posted by Ned Milburn View Post
Interesting. Basically a Spanish fan brace pattern blended into the main X.
Yes. I'd also like to try a lattice bracing on the lower face at some point. I'm far to OCD to go with the martin tone bars. I need symmetry in my life.
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  #163  
Old 05-28-2015, 12:51 PM
Ned Milburn Ned Milburn is offline
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Quote:
Originally Posted by Viking View Post
Yes. I'd also like to try a lattice bracing on the lower face at some point. I'm far to OCD to go with the martin tone bars. I need symmetry in my life.
Just remember, asymmetry is often used in soundboard design.
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  #164  
Old 05-28-2015, 12:58 PM
Viking Viking is offline
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Quote:
Originally Posted by Ned Milburn View Post
Just remember, asymmetry is often used in soundboard design.
I can see an asymmetrical design being a requirement for something like a fanned fret guitar, or even just a guitar with a cut away, but how does asymmetry help in a standard configuration? It seems to my mind, that even, symmetrical radiation of the string's energy would produce the best and fullest tone. Course, never having even completed a single guitar, that's just the musing of my own analytical mind.
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  #165  
Old 05-28-2015, 03:48 PM
TEK TEK is offline
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Hey Viking,
Good to see you are back at work on your guitar!
I say brace the top however you see fit and learn from there.
You are headed for one of the coolest times in a build, closing the box.
Enjoying following along.
Travis
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