Purpose of notching lining for tone bar ends?

HogTime

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Why notch the lining vs. not making the tone bars long enough to reach the lining? Is this structural strength related?

I'm working on a StewMac concert kit now and it requires the linings to be notched out. The first StewMac kit I built about 3 years back was a soprano and I don't remember notching it.

Thanks,
 
Others may use terms differently, but to me tone bars are the longitudinal braces that are also called fan braces and extend from the lower transverse brace to the tail. I've never seen a tone bar notched into the lining. The usual practice as far as I know is to sand them down to nothing just short of the lining. The transverse braces that are just above and below the sound hole are notched into the lining by most builders, though there are exceptions. This helps to discourage splitting of the top since they go directly across the grain.
 
Thanks for the reply. Improper use of "tone bar" on my part. :)

I see now that it's only the horizontal braces (on both top and back) in my kit that will require lining notching.

Sounds like the notching is more for tradition than something actually needed. Although, it looks like it would help keep the top/back from sliding around when gluing. I'll find out if that is true later. :)

Thanks,
 
Good, I'm glad that clears it up. The conventional wisdom seems to be that tucking the transverse braces is structurally important. I've heard of, though haven't actually seen, failures of tops on which the braces weren't tucked but maybe that's just a bad rumor.

Enjoy your build!
 
This is a good question. I asked the question a couple years back about whether it is good to cut through the linings and butt the transverse braces to the sides (To Butt or Not to Butt: That is the question?). As I remember there was no real consensus except from Howlett that it was probably "good lutheries practice" to tie off the transverse braces to the sides. I tend to agree. Since then I do tie them off and when the binding is cut in they glue to the binding creating a stronger structure. Does it decrease the flexibility of the sound board and effect response and volume? Frankly I don't really know but I suspect it does. Again it comes down to flexibility versus stability and therein lies the conundrum of design. I've never really come to a conclusion on this question, but I think it is important.
 
The problem I've seen on some old vintage island ukes that I've repaired is that the tops and backs shrink across the grain (especially on old dehydrated Koa) and the spruce braces push on the sides sometimes pushing through or pushing the bindings off.... I believe it's best to just have them half way into the linings leaving a small 3mm gap from the sides to allow for shrinkage.
 
I seem to remember seeing a YT video where Mya Moe stated the don't notch into the linings. They've made many quality ukes, so maybe Aaron Keim(forum member) from Mya Moe might chip in here to tell us if they have many failures.
 
Thanks for the additional comments.

I'm going to notch the linings per the instructions. Will be good training, if nothing else. :)

The soprano kit I made came with a Mya Moe video, so I'm assuming the kit came from them, too. Since it didn't use notched linings, it confirms the comment by mikeyb2.
 
The problem I've seen on some old vintage island ukes that I've repaired is that the tops and backs shrink across the grain (especially on old dehydrated Koa) and the spruce braces push on the sides sometimes pushing through or pushing the bindings off.... I believe it's best to just have them half way into the linings leaving a small 3mm gap from the sides to allow for shrinkage.

I do think about this little join a lot and I've come to the conclusion that in the end it probably doesn't mean much either way. The ends of the braces are going to be scalloped (or should be) and the area of contact is minimal. Plus it is just a crappy little butt joint and just made to fail as the instrument moves over time rendering it pointless from a structural point of view and possibly a point of buizzing which could be a disaster. So now I don't pay that much attention to the area and just get it close leaving about a millimeter or bigger and moving on. What ev. I got bigger problems elsewhere.
 
From the stand point of a little knowledge (a little knowledge is dangerous) it was ‘obvoius’ to me that the transverse braces should sit into the kerfing because it’s structurally stronger and neater, etc. However, I’m now thinking that gaps are ‘essential’. Reading this thread reminds me that Wood is different from other materials in ways that effect how it can be used. It’s a living material in that it expands and contracts with humidity and it does so at very different rates relative to cut and grain orientation, etc.

The brace and top are different woods and have their grain running in different orientations. For my education how do you match such features such that the woods expand and contract (equally) together, if they don’t then surely (depending on changes in relative humidity) the joint must fail, be prone to it or give in some way?
 
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From the stand point of a little knowledge (a little knowledge is dangerous) it was ‘obvoius’ to me that the transverse braces should sit into the kerfing because it’s structurally stronger and neater, etc. However, I’m now thinking that gaps are ‘essential’. Reading this thread reminds me that Wood is different from other materials in ways that effect how it can be used. It’s a living material in that it expands and contracts with humidity and it does so at very different rates relative to cut and grain orientation, etc.

The brace and top are different woods and have their grain running in different orientations. For my education how do you match such features such that the woods expand and contract (equally) together, if they don’t then surely (depending on changes in relative humidity) the joint must fail, be prone to it or give in some way?

You choose timber that is 1/4 sawn first. You build at a moderate RH so that the timber has some leeway for movement in both drier and wetter enviroments.

Building with a radius in the top and back further allows for them to expand or contract with changes to the RH. Though this certainly complicates the build of the isntrument, especially when it's the soundboard.
 
I think it would be fair to say that we build today to a much higher standard because of the way we now live. One dud instrument and your reputation is shattered as it is broadcast all over the internet what a useless builder you are.... Anyone building would do well to heed the advice given here - all of it good regarding notching. I do it for structural purposes and the bars rarely reach the limits of the ribs. However it is common practice in the guitar making world cut the notches through the sides to accommodate the oversize top, rout off and fit the bindings. All the big guns do this with confidence.
 
Yep.
What David said. I'd also add that by notching in the upper transverse bars and all teh back braces, it helps the braces from popping off due to knocks etc, and (2) it really stabilizes the upper bout area (im only talking transverse bars here) from movement.

also, i havent notched the linings in this vid yet, but id recommend doing this.


Others may use terms differently, but to me tone bars are the longitudinal braces that are also called fan braces and extend from the lower transverse brace to the tail. I've never seen a tone bar notched into the lining. The usual practice as far as I know is to sand them down to nothing just short of the lining. The transverse braces that are just above and below the sound hole are notched into the lining by most builders, though there are exceptions. This helps to discourage splitting of the top since they go directly across the grain.
 
If I'm binding I blow all the way through the sides. Easier and I believe stronger. When I play I'm prone to giving the instrument a violent slap every now and again. I figure some other players are too.
 
Thanks Beau. I tend to butt that upper transverse brace to the neck block and then back it off a tiny bit (1/8 inch) to leave a gap so that the top isn't tied to the neck block when I glue things down. I really think that butting the top brace to the block tends to stiffen up the top too much. It is a small thing sure. I think we must resist the temptation to tie off everything to make everything as strong as possible. Hello little tank. Hello dead ukulele.
 
If I'm binding I blow all the way through the sides. Easier and I believe stronger. When I play I'm prone to giving the instrument a violent slap every now and again. I figure some other players are too.

If you make the braces go all the way through, they can push out the binding if humidity gets too low. I try to leave a little gap.
 
My entire upper bout (from the transverse bar directly below the soundhole) doesn't move, so I lock it all in. WOrks for me.

Thanks Beau. I tend to butt that upper transverse brace to the neck block and then back it off a tiny bit (1/8 inch) to leave a gap so that the top isn't tied to the neck block when I glue things down. I really think that butting the top brace to the block tends to stiffen up the top too much. It is a small thing sure. I think we must resist the temptation to tie off everything to make everything as strong as possible. Hello little tank. Hello dead ukulele.
 
I have been thinking about my statement and thinking it might be wrong so I've decide to flame myself:

I tend to butt that upper transverse brace to the neck block and then back it off a tiny bit (1/8 inch) to leave a gap so that the top isn't tied to the neck block when I glue things down. I really think that butting the top brace to the block tends to stiffen up the top too much. It is a small thing sure. I think we must resist the temptation to tie off everything to make everything as strong as possible. Hello little tank. Hello dead ukulele.

Sequoia writes: That is a stupid way of doing things. Everybody knows that you butt the upper transverse to the neck block extension. This allows the instrument to become one piece and lets the neck become part of the resonating whole resulting in a fruitier tone. You are an idiot!

Sequoia responds: Your mother worked in a flip-flop factory ukulele boy! Any idiot knows the neck plays no part in resonance of an ukulele. I think this thread should be locked!

(self flaming)
 
Any idiot knows the neck plays no part in resonance of an ukulele.

haha- well, all i can say is that i bet that two otherwise identical ukes, but one with a neck attached and one with a neck that isn't attached, would sound different- maybe better, maybe worse...probably worse.
I think necks contribute to more overtones rather than in your face, 'direct' tone (for lack of a better term).
 
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