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I decided to use a neck extension block and I eliminated the upper "thin" brace as on my drawings. The upper face brace is 13/16" tall. It looks huge. If I'm using a neck extension should I cut my upper face bracing height down? Clintoncrich38801.6510069444

Looks a little high to me, but whatever works.

Al

I use 9/16" ...just enough to hide the edge of the plywood "paddle"...looks traditional still if you're peeking inside the soundhole...

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I don't use an upper graft & I make the upper transverse brace about 1/2 wide & 5/8" high.
It might be better to feather your short baces down to nothing at the ends to prevent glue failures at that point.
Looking good!
I don't scallop the upper section of the X braces anymore... Though it looks really cool through the soundhole.

I extend the two 'A' braces on either side of the soundhole up through the shoulder brace, and inlet them into the 'chin'. It helps to keep the neck from shifting inward when the guitar gets dropped on the back of the neck.

I wondering about any advantages of sanding the ends down. That's tuff to do without hitting the sound board. Maybe I'll use some tape to protect it. I don[t understand how this prevents glue failure? Can you explain. Thanks for all the suggestions! CLinton

Hey Critch;
If you leave an abrupt end on an untucked brace, the flexing stresses concentrate at the brace end. If you feather the brace, the tip is able to flex with the top, which spreads the load over a larger area.
If you use a sharp chisel with the bevel down, you can feather the brace end to nothing. As you approach the tip of the brace, lean down on the handle of the chisel gently & it will cut in an up curving motion.
The thin glue line will actually help you out by resisting the cut & riding the chisel edge up level with the top.
Use a chisel which is only a little wider than the brace, so the corners don't dig into the top if you aren't perfectly flat to the top.
Does any of this make sense??? It's pretty hard to explain in words. Come on over for a coffee & I'll show you!

Yeah, it's makes sense, just never looked at it that way before. Thanks for the explaination, I would lay in bed at night and drive my wife crazy thinking of things like this. Thanks all ! Clinton

Just wondering how you are going to attach the neck? Bolt on butt joint?

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Joe Beaver
Maker of Sawdust

I build most of my guitars with peghead adjusting nuts on the truss rod. I mention this first because I will not have truss rod access hole in my upper transverse brace. That said the upper transverse brace main job is to make the area above the sound hole rigid and carry the torque load of the neck and FB extension and prevent the top from bowing in from this torque load of the FB extension. You can achieve this with wider but lower brace or taller and thinner. either works if you provide enough strength to resist the load. On small body guitars I us 9/16 wide x 3/4 tall.

Also as others have stated. If you do not tuck a brace into the lining, then feather it to zero to eliminate stress risers.

I was bolting on with a tenon and mortise. As you can see from the pictures I'm planning on using a extension block that is glued to the neck block. Thinking that with that I won't need a large upper face brace and therefore maybe shave that puppy down. I was wondering how much can I shave. Clinton

Why take material off the shoulder brace? The only guitars I've seen where that part of the soundboard does much at low frequencies are archtops. Leaving that brace tall almost certainly does not hurt the tone, the weight is hardly an issue, and you might find you want the strength, even with the chin there.