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What is the best way to shave down bracing on a finished guitar without removing the top? I have come to the conclusion I over-built the top on my acoustic lap slide. They are 3/4" tall in the center and are not scalloped on the lower legs, they just gradually taper down to about 1/8" to fit in the pocket of the kerfing/sides, similar to the upper legs.

thanks,

Damon

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Damon Wack
https://www.facebook.com/LindamonGuitars

this is a skill that takes a little time to learn but is a good skill to learn.. What is the width of your braces ,also scale length and size of the guitar. Also how thick was the top. What gauge stings are you using ?
I use a 9/16 high brace. Is this your own design?

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Those are the same dimensions I used for the braces on my first steel string. They're what is suggested in Cumpianos book.
Instead of shaving them, I converted the guitar to a 12 string.

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Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

I'm wondering how you came to the conclusion that it is your bracing? How old is the guitar? Sometimes they take a while to open up.

The X-bracing on this guitar is 3/4 tall and 5/16 wide., and not scalloped at all, just tapered. On previous guitars I have built (5), the X-bracing was 5/8 tall and 5/16 wide, and well scalloped. On all the guitars I have built the top ranges from .095 to .110 depending on the stiffness I am looking for. On this particular guitar the top was .095. It is Sitka. All of the previous guitars I built were far superior in tone and volume, and two were remarkable. This guitar is thin throughout the range, but especially so in the upper registers, specifically the top two strings ( .018 and .017). It may loosen up some, but is is far below what the others were. I have also had the opportunity last weekend to play some other lap slides that were fairly new, and they were all far superior to mine. I'm pretty sure it's over-braced.

The pull of the strings when tuned to standard GBDGBD tuning of a dobro is around 200 lbs, so I beefed up the bracing, increased the size of the bridge reinforcement plate, and instead of the bottom tone bars I added another X-brace as shown below. It's notched to fit over the bridge plate, I was hoping to derive some pumping action of the lower bout with this. The width of this brace is 1/4 X 1/4, as is the single tone bar below it and the other side bars by the main X. All of these braces are scalloped.

I like the idea of turning this into a twelve string, I had trouble slotting the uncompensated bridge I built (a previous post), so I glued on a Stew-Mac compensated bridge. This bridge will split at some point if I keep it a lap slide because it is not built up enough in front to account for the higher saddle. It is, however, a 25" dobro scale, so it's a little shorter than an acoustic guitar scale.

I think the best solution is to make it a twelve string, but I would still like to scallop the main bracing some and see what effect that has on the sound. As you say, John, this is a good skill to learn!

Sooo....what is the best way to do this?

thanks, Damon

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Damon Wack
https://www.facebook.com/LindamonGuitars

I had to make a new neck/headstock to accommodate the extra tuners, and drill more holes in the bridge for the 6 additional pins (the bridge was extra wide, so this worked out great), but that's the only mods I made.

You may have to use the shared pin method, which someone around here has posted a tutorial for.

Let us know how it goes. I'm very happy with my 12, though I think I'll be making another new neck for it. This one is maple, and so too heavy, also there's a big hump at the neck/body joint because I didn't set the neck angle very well....

_________________
Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

I'm going to have to make a new neck anyway because it's a squareneck right now! Kinda hard to get your hand around!

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Damon Wack
https://www.facebook.com/LindamonGuitars

Interesting that everyone is addressing the question "should you trim the braces on your build" rather than "how to trim braces on an existing build". Sorry I don't have the experience to help you or I would advise.

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Formerly known as Adaboy.......

Hey Damon, I've gone in and refined the bracing on a few of my builds. I use a small stamped metal stanley plane I had in my junk drawer. Hacksawed off the nose and some of the tail to shorten it and sanded a bit of a radius into the nose to help it with the scooping action. Works good, I'm sure some of those little brass finger planes would be ideal. Then reach in and go to work, it's rough on the forearms and I've learned to prefer larger sound holes, they sure make inside the box refinements much easier. Then clean up with sandpaper.

Shave a little, restring it and see how it's working for you. Going slow is a pain with all the re-stringing but it's the only way to feel your way to what you're looking for. You can spread it out over time also to give it a chance to settle in to the changes your making.

It sure beats living with a less than satisfying box.

Good luck,
Joe

I am sure a small plane is the correct tool for this job. Adjusting the bracing of my first guitar, I had no success with the little plane I have (and my limited skills). I love using planes and chisels to carve braces, when I can see, but it's pretty difficult when working blind through a soundhole.

As an alternative, I made a few small (about 3" X 3/4") sanding blocks, some curved and some straight. I started with coarse paper which cuts pretty fast. Even so it's slow work, but you don't want to remove too much at a time--it may not take much to get a big effect. Keep re-stringing and testing as Joe says.

Don't forget the back braces. Following Alan Carruth's instructions to tune the back to complement the top, I took a little bit off the the largest back brace. I knew Alan was very knowledgeable, but I was still dumbfounded when the sound dramatically improved as he had said it would.

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Tim Allen
"Never hurry, never rest."

I also mostly use sanding blocks. You can drill a hole in the back to make them fit over a finger. 80 grit will take braces down pretty quick.

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http://www.chassonguitars.com

Why not leave it as a 6-string slide and try to work with it?

You made a comment that the "Standard" dobro string tension is about 200 lbs... and so you beefed up the bracing and bridge plate.... Did you take into account that the "Standard" Martin Style Dread running Medium strings on a 25.4" scale also has about 200 lbs tension........

Since this is the case..... you may want to try it out with Heavy strings and see what happens....

But... In any case -- What's the balance like? You mentioned flat sounding trebles....
Try out this 1st:

Measure your string heights at the first and last fret markers....... Use automotive feeler gages to get a good measurement -- rulers aren't particularly accurate....

The typical slide setup has tops of the strings are all flat........ but they may not always be level -- aka, the high E may be tallest and the low E may be shortest over the body, or vice versa..... This changes the balance of the instrument quite a bit....

Try adjusting your nut and saddle so that the treble strings are either level with the bass strings, or a bit higher -- and all strings flat across the top.

The other thing that comes to mind is the super-duper beefy bridge plate.... Not much you can do about that now... but you can try sanding the thick belly part of the bridge behind the bridge pins some.... Don't touch anything in front of the bridge pins if you can help it... You can try this out with strings on the guitar -- so you can sand some, then play some and see what happens..... Be sure you carefully mask the guitar top or you will wreck it!

Here's the caveat with sanding/adjusting....... Go Slow... Only do a little teeny bit at a time... It is easy to take it off... Hard to put it back on. Sand a little... Play a lot....

Thanks

John

You are right! Though it is a ligit question because I have seen guitars I thought were muddy sounding and stiff open up nicely.

I would probably make small cork lined sanding blocks and use 60 grit paper, possibly use a scraper to though scrapping spruce is kind of an odd experience.