Purpose of notching lining for tone bar ends?

Sorry to be late to the party, haven't been on the site lately. I totally see how notching the linings is a good idea. I think that Beau, Allen, Pete, et all are doing top work and whatever they say is worth listening too. At Mya-Moe, we have never done it. I do all the warranty and repair work for Mya-Moe, so I have seen it all. When a uke takes a hard hit to the top, we do sometimes get a loose brace end. But in that case, the top is usually cracked anyway and I'm not totally sure that notched linings would have solved the problem. I have noticed that feathering the brace ends down to paper thin, instead of leaving them square or stocky, makes the brace end more flexible and less likely to pop loose under pressure.
Cheers
Aaron
 
My experience of working in metal rather than wood encourages me to believe with Maya-Moes practice is the better of the options - though the alternatives obviously work well enough too - it’s better both for ease of use and in load distribution. With metals a sudden change in thinkness causes localised stresses to increase which, without other care, leads to parts breaking. I can’t see why wood should be any different in that respect.

Thoughtfully building flexibility into structures makes them more resilient and overly stiff structures are more likely to fail than those with a degree of give built into them. Though it might be counterintuitive flexibility can, dependant on the circumstances, be a very good thing: I find pneumatic tyres are far more fit for purpose than sold ones and trees that bend in the wind are the ones that break less often, etc.
 
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I can’t see why wood should be any different in that respect.

Uh, because metal is homogeneous with consistent structural properties in any plane through the material (in the absence of manufacturing defects) and wood isn't?

What Pete said about best practices, with due respect to MyaMoe's excellent record.
 
Uh, because metal is homogeneous with consistent structural properties in any plane through the material (in the absence of manufacturing defects) and wood isn't?

So what you are saying is that a sudden change in wood thinkness does not cause localised stresses to increase and therefore there is no danger of those parts breaking. If so then that’s rather interesting, I would agree that wood and metal can fail in different ways - some properties are common and some are not.

What Pete said about best practices, with due respect to MyaMoe's excellent record.

What are best practices and who decides? Is best practice something that you do because you have discovered that that is the best way for you to do something or is it something that you do because you copy others? Often we use ‘best practice’ when you’re not certain how something else might turn out. Tradition is a form of best practice but should always be questioned. I understand that Pete’s ideas on many things have been challenged, changed and evolved over the years; isn’t that true of forms of best practice too? Anyway, why does something have to adhere to ‘best practice’ - what ever that might be - when another way of doing something can deliver perfectly satisfactory results?

All that aside you’re the Luthier, you build fine stuff so your beliefs are working right for you.

The counterpoints have been answered and I made my main comments in #22, no point in debating further and I too (see #19) think that this thread would be best locked, too much dispute coming out of it.
 
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What are best practices and who decides?

In the case of an arcane and traditional craft like instrument building, hundreds of years of success is more helpful in identifying best practices than is a Gedankenexperiment about what might be. Just ask Schrödinger's beleaguered cat. :)
 
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I don't think the thread should be locked at all. I was just joking in reply #19... I think this is an important question and not trivial. For what it is worth, I've done it both ways and no longer notch and butt mainly because it is a lot of extra work and just taper the thangs up to the linings. I think maybe a good point that was missed is that butted braces can expand under certain conditions (i.e. high humidity) and push against the binding (weak point) and cause them to fail (i.e. come unglued). Not a good thing. I forget who pointed out this potential failure and I'm too lazy to track it down, but it is certainly a point to ponder.... Oh and I looked up Schrodinger's cat; not sure how that applies to building ukuleles, but it is a cool thought. Poor cat. Or not.

Schrödinger's cat: a cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal monitor (e.g. Geiger counter) detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison, which kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead not both alive and dead. This poses the question of when exactly quantum superposition ends and reality collapses into one possibility or the other.
 
I always tuck the transverse braces into the linings. Having repaired many vintage instruments, a transverse brace seems to curl up on the ends over time if left untucked. As far as cutting the ends of the braces so they do not make contact with the sides, rarely have I seen the brace push out the sides, only in very thin sides and very old have I seen this happen, and only in Koa ukes. I have never seen in happen in a guitar of any age. Just my observation as a repairman.
 
This post has to do with x-braces on guitars but is instructive nevertheless:

http://luthiersforum.com/forum/viewtopic.php?f=10101&t=50143

Sequoia, the cat "experiment" has some relevance to thought processes but doesn't directly bearing upon wisdom in ukulele building. The point is that thinking doesn't necessarily get you there. After all, we're more than a century into quantum mechanics and can't tell if the poor kitty is dead or alive. ;)
 
Best practice is attached to current thinking that is articulated by common experience. This is sometimes static and some times evolving. It is nevertheless an established paradigm. Those of us who work at this business in a professional capacity often have to take positions because the luxury of experimentation is for those who already have an income. If you have anything about you, you will do the research, make your mistakes and arrive at something that works consistently without failure - hence best practice.

Side bar - it always amuses me how much hair splitting goes on here...
 
One can only hope the cat won't eat the poison and scratch the creep who put him in there eye out when he looks in the box.

The braces don't expand in length. Humidity will not lengthen quarter sawn wood in that direction though the top or back wood can shrink having the same negative effect.
 
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Side bar - it always amuses me how much hair splitting goes on here...

Well amusement is half the fun of the forum isn't it Pete? Glad to hear you are amused...

The braces don't expand in length. Humidity will not lengthen quarter sawn wood in that direction though the top or back wood can shrink having the same negative effect.

This is a good point and I agree... I guess my hairsplitting point is that perhaps this join is trivial and ultimately weak and of no consequence either way so why put in all the work of making it in the first place other than it is "standard practice"? I just don't see the structural gain and I do see possible acoustic loss. Sometimes simpler is better?
 
Sequoia, you may be right, May not make much difference. I have always made the notch thinking it added strength, but I have just finished making three Kasha tenors and the soundboards have no transverse braces, just twelve smallish tone bars, none of which reach to the sides or under the linings. It can't be as strong a top as a traditional two transverse brace tenor, but boy do they sound good. More of the soundboard is vibrating. I'm not planning to play tennis with that uke so I think it is strong enough.
 
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