finalizing top bracing

[turnertj]

Hey all...

Got a question about the fitting of the x-brace with all the other components - finger braces, tone bars, bridge plate, etc...

Do all of those components fit completely under the entire x-brace, or just a small portin to hold them down better? I guess in particular I'm asking about the bridge plate. Do I need to notch out sections through the entire brace width or just at the edge to tuck it under?

Thanks!

[tippie53]

In the pre war days the braces were all tucked into the X brace. This is a matter of choice . You don't have to do it that way. Modern Martin guitars have the bracing joint butted against the main X braces. On the top only the Truss rod brace and main X braces get inletted into the kerfing.
All other bracing is faded to the top just short of the kerfing. All braces on the back are inletted to the kerfing

[turnertj]

Thanks John...

What do you recommend for bridge plate material? I have some appropriately thicknessed maple and EIR. I've read there is a difference between them. Any recommendations?

[tippie53]

Avoid the EIR , When I look at bridge plates I want something very hard and cut off quarter. I also like the grain to run about 45 degrees from the top grain. I don't like all the bridge pins setting up on the same grain line.
Hard maple has been used for many years and is proven . I have used osage Orange , Brazilian rosewood , black locust and even cherry.
This is one of the cup is half full or half empty. I do like the maple it is proven and it works. It glues well and is easy to repair should the need be. Osage orange also works and to be honest , I can't say I hear any real difference.
Size is a big thing here , you need it to do the job so don't make it over sized. Here if you tuck bracing you can get away with a smaller plate. Martin used 1 3/8 wide when they tucked braces then went with that monstrous surfboard later. Many of them were pulled to be replaced with the more modern 1 3/4 plates we see today. Here is a bracing library reference from the UMGF. It may prove interesting .

http://theunofficialmartinguitarforum.y ... wmZA4GLOwo

[turnertj]

Perfect, thanks John. Exactly what I was looking for. I'll go with the maple.

[turnertj]

Hey guys...

Do any of you use a diamond shaped centerline seam reinforcement on your soundboards?

Also, and this is going to be a REALLY dumb question (remember I'm a rookie...) What is the purpose of the tonebars? I'm assuming they help refine the frequencies that the soundboard moves when subjected to the changing string tension. The reason I ask is that I'm building a fairly small bodied guitar, and the plans that I am using (modifying to use actually...which is where the problem comes from) have two tone bars. But I've found many other examples online that only use one is such a small bodied guitar.

Thanks...

[tippie53]

I don't use a wooden cleat there as I have seen them loosen. I use a cloth patch. Use what you like but you need to allow a touch of movement on the patch. On the area at the end of the patch taper the ends so there isn't a sharp corner and it can wiggle a bit in the area on the edges.
That seems to create a stress riser to loosen the glue joint. Either one will work .

[ckuo]

Hey there,
There's nothing dumb about those questions. I'd say it's great to be asking about the form and function of top bracing since they influence the sound of the guitar greatly. Here's a question for you - how is your x brace joint? Is it tight? Is it capped? I only ask because that was my big fail on my first guitar.

-Charles

[turnertj]

I just made the jig to make my x-brace. I actually made a few x-braces, but wasn't happy with either of them. I'm making another jig next to hold an interchangable pattern for shaping the braces to rough shape before glueing. There's no way I'm glueing down a full brace block without pre-shaping and then using a chisel. I just don't have that much skill. I will make it very tight, which I already managed on one of my trials, and then I will cap it as well.

John... when you say you use a cloth patch instead of the cleat, how big is the patch-the size of a cleat, or longer, i.e. the length of the seam between the tone bars, etc?


Thanks...

Tj

[tippie53]

I use about 1 inch round cotton patch