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While watching Robbie O'Briens/LMI latest Tips du Jour video on acoustic guitar top bracing, he states that he glues the ends of the braces that come in contact with the x-brace, to the x-brace.

I would like to know If I compromised the stability of the top of my weissenborn style guitar by not doing this?

I don't recall reading about gluing the brace ends to the x-brace in Tradition and Technology either (It's possible I overlooked it), which I'm using as a reference guide during my first build. Is this common practice?

Also, since I don't recall reading about this in Tradition and Technology, my thinking is that perhaps this is something that some builders do, but not all. I'm very interested in your comments, thanks.

Ron M.

Not all builders do it but I take the view...what do you have to lose by not doing it? I picked up the habit during a guitar building course run by Paddy Burgin and Dave Freeman.

If youve already braced up your Weissy and not put glue between the X brace and tone bars then I wouldnt get too worried about it.

Cheers Martin

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I feather the ends of the tone bars and finger braces to paper thickness towards the x-brace so no glue needed there. I inlet the "A-brace" legs above the soudhole into the upperer x-brace arms, and I do glue these in. If you do not inlet, I don't know if glue is going to make a whole lot of difference; I mean, its a very small end grain glue surface just butted up against a brace? I think inletting or feathering is the best insurance against these brace ends popping lose for whatever reason.

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Rian Gitar og Mandolin

I'm an inletter, all of my braces that meet the X are inlet into it, so that the whole bracing system is connected intimately.

For instance all of the braces, tone, finger, A, and the brace behind the bridge plate are all inlet into the X. The A is then inlet also into the headblock.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Good Morning Everyone,
Thanks for your replies. I thought not doing this was a big mistake. I made enough mistakes on this guitar, don't need anymore. Thanks again.

Thanks for posting the photo Colin.

Regards,
Ron M.

I am a butt man myself and just butt my brace ends to the X and then feather them away to nearly nothing. In the process of gluing these braces some glue will unintentionally migrate to the butted end which is fine with me. But again in the feathering it is sliced off.

I also think that inlet braces can complicate repair but braces that are not inlet are "perhaps" more likely to come loose too. Then there is the issue of how where the braces intersect the X the top gets very stiff and flexibility is needed at these intersections since we are not making bank vault doors.......

Ron buddy I think that you are fine and would not worry about it.

Any joint between two pieces of wood that is not glued has a potential to buzz. Even though the end grain does not bond well it does bond some. Gluing brace ends is a small bit of insurance against problems for me more than any measurable difference in tone.

Greg N

New York Martins had the bridge plate set into the X. This stopped long before WWII. I have never seen a Martin with tone bars or finger braces set into the X.

I can't see much point in an end grain butt joint that is likely to break loose and create a potential buzz. It also makes the brace that is butted more likely to separate on its glued surface to the top if the top is struck a blow at that point.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard, do you tuck them?

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Colin, I do know of some 12 step programs for this problem.

Just kidding, of course!

From an outsider's viewpoint, as I have yet to build, yet with lots of wood working experience and a mechanical engineering background, I opine the problem is minute. The force required to break the glue is much more than to break the grain of the X-brace. The end grain of the finger brace, unless finely sanded, will have a better mechanical/chemical bond with the glue than the glue to the side of the X-brace. The X may split or at least loose a few thou of wood.

If the instrument received a blow strong enough to dislodge this bond you are going to have greater issues with the top.

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Steve Walden
Aspiring Builder,
Bartlesville, OK

I subscribe to the entire bracing system working together. Like a system of rivers transferring the vibration from the bridge down the braces and out the fingers.
I use to tuck them, I butt them now with a well fitted joint.

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Lance@LuthiersForum.com

I agree with Todd !
As a repairman for over 30 years -a tucked brace that's let go is a "B" to reglue!

If you need extra stiffness for a 12 string or Harp Guitar then glue your little braces to the X.

But for a well planned & made guitar -there is NO reasom to do it!

I want my tops to be alive!!

Mike

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Mike Collins

The last thing on my mind when I'm bracing a guitar is "Oh dear, this will be difficult for a repair man to reglue in thirty years time". If it's difficult, tough, I have no interest in the repair man's problems, I'm building a guitar to sound the way I want it. I like my braces to act as a single integrated unit, and to achieve that I inlet them to form a single integrated unit. To say that there is no reason for a well planned and made guitar do it without reference to the particular design and voicing is I'm afraid too sweeping a statement to have any basis. Some of the best makers I know inlet all of their braces, I'd better tell them to stop as the repair guys don't like it .

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Here's my take on that.
I have used well fitted butt joints for the finger brace ends at the X for a long time. Recently I put a slightly heavier set of strings on a 5 year old very lightly braced personal guitar and it caused the end of the strut on the treble side to come unglued for about the first inch coming out of the X brace. It caused a nasty buzz on the high e string up the neck. I thought it was (and sounded like) a fret that had popped up, and when leveling the frets didn't take care of the problem I started looking around inside and found the loose brace. I have always used light gauge strings on the guitar and I tried a set that had a slightly thicker core and the extra overall tension was enough to cause the problem. This is a parlor guitar with a relativley thin cedar top, so there was quite a bit of distorting of the top. The struts comes right off the upper corners of the bridge on this guitar, and that is where something would let go if it had too, right beyond the bridge/soundboard/bridge patch "sandwich" area. The X brace was also scalloped. There was a notable increase in distortion of the soundboard with these strings, so I wasn't surprised when I figured out that it had popped a brace end. It sounded great before that though!
The last few guitars I have put together have had notched braces.
I think that if your a builder who likes a thicker top (and don't want to see any deforming of the top when strung up to pitch) there shouldn't be a problem with the butt joint approach, but if you are taking things down to minimum thicknesses notching makes sense. It only takes a tiny bit of effort to notch a brace in and lock it in to keep a brace end from coming loose. It' a good idea to make sure you are using well quartered, split braces here too. I have repaired guitars in which the brace bottoms stayed glued down but the not-well-quartered spruce brace (getting close to slab cut) gave it up between the grain lines.

Howard my friend I am not sure if you feather them away to nothing or what too?

Please enlighten us?

Whether it's enlightening or benighting is uncertain. I inlet a pretty substantial amount of the X ends in the upper bout, almost none in the lower bout. Most braces get tapered to the top where they meet the X, but some taper faster than others. The two higher finger braces don't get tapered quite to the top at the X, because they fall under the bridge and are therefore protected from getting knocked or flexing loose. They also get a little inlet to the liners at the other end. I see those two finger braces as important to keeping the bridge from rotating forward too much. Lower face diagonals feather all the way to the top at both ends, but feather further back at the lower end. Upper bout transverse gets a substantial amount of inletting to the liners.

There are lots of systems that work. If it doesn't make sense to you, my advice is to do something that does. And think of the bracing as a system. What you do in one place affects what you do elesewhere.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

It sounds like you have had the good fortune not to have one of your instruments come back to you for repair. Am I hearing you say that should a brace somehow pop loose on one of your itstruments, that you will tell your customer that it is now "some repairman's" problem? Good luck with that attiude, my friend .

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It's not the miles ahead, it's the stone in your shoe


In Markham,Virginia

I was taught to set the tonebars into the X brace and the finger braces just get glued on...

No, what I'm saying is that to build a guitar with the attitude that you have to make it easy to repair is one of the most negative and depressing things I've heard in a long time. Ford may build their cars from 15000 parts all sourced from the cheapest tender, knowing that some of them will fail and their cars will need repair, but Rolls Royce only build with the best materials to the best design knowing that their cars will only need repair if the owner does something stupid. I thought we were trying to build Rolls Royces not Fords.

And no, I've never had a brace come loose on any of the guitars or lutes I've made over the last ten years or so. I've repaired a lot of instruments, all from the 19th century and earlier, some in the £100k range, and very rarely have to reglue braces, but then they are the Rolls Royce instruments, they were built well to start with.

So I will continue inletting my braces into the X, and the UTB and upper arms of the X into the linings, and if that's a problem for some future repair man so beit.


Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I am not really sure of why such a controversy? Surely sometimes there is too much made of these very subtle differences and there are strong arguments for both... at the end of the day if what you build sounds good, and you and your customers are happy with the result does it actually matter?

I appreciate some of you love the science and indepth analysis of the acoustic engineering of these wooden vibrating structures we build... and thats fine, but ultimately I think one of the best aspects of building wooden instruments is the mystery associated with it.

Its logical to look for practical solutions to the problems faced by acoustic instrument designs but I dont quite believe there is s right or wrong between whether your braces are joined in some way surely? I have played guitars with both and each have their own charms if the quality of the tonewood is high and they ahve been well made.

Taking the quality of instruments made for yourselves or your customers seriously is important, but there does come a point where it can be taken TOO seriously?

I prefer to think that I am trying to build Aston Martins......

I've started doing something different on the last couple of guitars. I like the idea of tying the braces together to work as a unit, but I was bothered by cutting lots of notches in the x-braces since I worried about the loss of stiffness this might cause. So I came up with a pinned joint that seems to work fairly well. I butt the end of the tone bar up to the x-brace and drill a 5/64" diameter hole through the back of the x-brace that extends into the tone bar about 1/4". I then insert a wood toothpick into the hole when gluing the brace into place. The pin adds negligible weight. And the small hole in the x-brace should not cause any loss of stiffness. The only complication comes from finding a way to drill a hole parallel to and about 1/8" above the top.

Barry, why does notching the x-brace close to the soundboard cause loss of stiffness, as long as the edge facing the inside of the box (where the shear force is greatest) remains intact? And how do you drill those holes...?

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Rian Gitar og Mandolin

Arnt, Notching removes nearly half the x-brace so I worry what that might do. I have no data to support this, however. I know the joint will be stiffened somewhat when the brace is glued in, but there is no way to glue a splint over the one-sided joint like we do at the x-brace joint.

I drill the hole by making up a drill bit holder. I take a 1/4" wood dowel and drill a centered hole in the end and glue the drill bit into this. Then I chuck the dowel into the drill and hold the dowel against the top while I drill the hole. This ensures that the center of the hole is 1/8" above the top, which seems to be a good location for the size of my bracing.

So far, I have only done this pinned joint on my tone bars. It seems like it might be overkill for the finger braces, but I might eventually try it there too.