Thinned and braced top of a small body guitar

[Henning]

Hello, i'm going to set a splint in the crack. Bur otherwise, do you think this top can be the part of a well sounding and long lasting guitar?
If not what should i change, please?
It's not over braced, is it, please?

https://www.dropbox.com/scl/fi/bvcbb...htlktb9il&dl=0

https://www.dropbox.com/scl/fi/tc8p0...mbjnf1fbk&dl=0

Regards

The top is thinned to 2,4 mm except above the bridge where it is below 3 mm. The thickness of the bridge plate is a little less than 3 mm. I used a 1/4" width for the bracing.

[Fathand]

Do you mean the X braced top or the other? How wide?

When you say carved top, do you mean arch top? Is there a pic of the front?

[Henning]

Hello Fathand, I've changed the headline. The question is only about the top and it's bracing. I am sorry, when first uploading the photos, the second happened to be a one of the old fan bracing. It's changed now.
I do understand if it is difficult or perhaps rather impossible to answer. But if you can see if there is anything that seems wrong about, that can easily be improved.
I try to tap-tone it, but can't really say if I'm "done" or not. So that's the main question.
I kept, or rather tried to, keep the original lacquer. It's much darkened to dark yellow or light brownish.
My doubts are about it being such a small body (body length: 40 cm, body width lower bout 32 cm, body depth 8 cm) it will not be that easy to get a good bass out of it.
Regards

[printer2]

Is the bridge plate wider than the bridge?

[Henning]

Originally Posted by printer2

Is the bridge plate wider than the bridge?

Yes, it is.

[Fathand]

I just built a similar sized guitar, about 12 1/8" wide. I call it a size 2-14 fret.
Mine is almost 4 " deep maybe 9.8cm, 3.5" soundhole. My top is .095" thick Sitka. It has very good volume and tone.

My bracing pattern is the same as yours. My bracing is 1/4" 6.35mm wide, 9/16" 13mm tall. Your transverse brace looks heavy to me, mine about 8 or 9mm wide. Also your soundhole bracing, mine is flat like popsicle sticks.

[Henning]

Thank you!
I have been removing slightly from the peaks of all the crests, lowering them to be comparable to what the Grellier plans indicates. Supposedly, the transverse bar area doesn't contribute very much to the tone. But I intend to make the slant form longer to remove some mass there, out of balance reasons. I had to make a thicker sound hole bracing to straighten the top. What if I taper the tone bar to zero to end on the top instead, perhaps an inch or 1.5 inches from the edge of the top? How would that effect the tone and response of the guitar, please?

[LHawes]

Originally Posted by printer2

Is the bridge plate wider than the bridge?

Please take this observation with a grain of salt but from what I've read and seen here about top bracing and bridge location isn't it typical or advised to have the corner wings of the bridge bear on the 'X' brace to keep the bridge/top from rotating too much and more importantly to keep the area in front of the bridge from sinking too much? Scale length might also be important as a longer scale will put more stress in the locations both in front of and behind the bridge.

The current bridge plate location and size relative to the smaller bridge size seems like it might set up the bridge for excessive rotation and/or the top in front of the bridge for excessive movement or sinking. Curious what others think.

[printer2]

Originally Posted by LHawes

Please take this observation with a grain of salt but from what I've read and seen here about top bracing and bridge location isn't it typical or advised to have the corner wings of the bridge bear on the 'X' brace to keep the bridge/top from rotating too much and more importantly to keep the area in front of the bridge from sinking too much? Scale length might also be important as a longer scale will put more stress in the locations both in front of and behind the bridge.

The current bridge plate location and size relative to the smaller bridge size seems like it might set up the bridge for excessive rotation and/or the top in front of the bridge for excessive movement or sinking. Curious what others think.

I asked because I did not know the size of the guitar and did not know how the bridge plate size related to it. If the plate was larger than the bridge I would have no concern (was concerned on the tall bits of the braces but the OP already adressed that).

[redir]

I think what LHawes is pointing out, and I agree, is that the X-Brace angle does look pretty wide at least in the pics. You definitely what to have the corners of the bridge wings over the X-Brace for reasons mentioned including the bridge delaminating from the top. I had this happen on one of my early guitars and regluing the bridge didn't work, I had to make a longer bridge that went over the X-Brace arms and it has been stable ever since.

By eye from looking at the pics it looks like you are going to have to have a very long bridge to accomplish that. I would also say that the bridge plate is pretty thick looking but otherwise doesn't look over braced.

Question in the first place though, why are you using that broken up top? IS this from some vintage instrument? Do you have the bridge? If so lay it across the bridge plate on top of the bracing in the approximate position of where it should be based on scale length. Do the wings go over the X-Brace?

[Henning]

Thanks for your answers and questions. The guitar is from 1948 so is the top. It has a ridiculously wide bridge i.e. long wings. Horizontally the bridge will stick out of the x-brace some 2-3 mm in the top corner of the bridge on both sides.
The x-brace angle is +90 degrees, less than 100, probably less then 95.
What about the ending of the x-brace and tone bar? Should i remove some wood there, please?
The x-brace cross is 15 mm, the x-brace crests are 11 mm, the tone bar crest is 10 mm respective 9 mm. The x-brace low is 6,5 mm and the tone bar low is 5,5 mm height.

https://www.dropbox.com/scl/fi/9btri...g4ue6w3cm&dl=0
https://www.dropbox.com/scl/fi/bne5t...an0b5al2k&dl=0

Once again, thanks for your concern and attention. The scale length is 580 mm. https://www.vintage-guitars.se/Levin...orita_info.php
Kind regards

[redir]

Ok so I assume you are following the original bracing pattern? Or was this a ladder brace guitar? Anyway sounds like you got that covered.

Nonetheless some people like to tuck the brace ends into the linings some don't. I build one small parlor guitar that I tuck the ends in at about 1/8th inch thickness. All other guitars I feather to zero and glue the linings right over the paper thin edges. I only do it this way on the parlor guitars b/c the very first one sounded fantastic and I want to replicate it.

Otherwise loosening the top up by thinning the braces as they approach the sides is a common practice that makes sense acoustically.

[Henning]

Originally it was fan braced, designed for either steel or nylon strings(!?), with a top thickness of 3,7 mm.

[RJVB]

Originally Posted by Henning

Originally it was fan braced, designed for either steel or nylon strings(!?), with a top thickness of 3,7 mm.

3.7mm seems thick for a nylon string top if it has to have any kind of volume. NB: nylon strings were put into production in 1948, same year as the guitar - and I have no idea if at the time these novelty strings already allowed higher tensions than were common with the gut trebles and silk basses that were prevailent before. But I may be wrong if the guitar was originally fan-braced

[Fathand]

Originally Posted by Henning

Originally it was fan braced, designed for either steel or nylon strings(!?), with a top thickness of 3,7 mm.

Since you are changing to X brace, are you going to be using steel strings and a pin bridge?