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Sorry, but a 10% reduction in thckness of a rectangular part in bending results in a 27% reduction in stiffness or force to yield, not a 35% reduction. THIRD power.
you forgot the extreme fiber distance (c) from the moment axis:

Stress = Mc/I

I = bh^3/12, b = base width, h equals height and strong axis dimension

c = h/2

substitute and solve:

sigma = M *(h/2) / (bh^3/12) = M*12/(2*b*h^2) = 6M/bh^2

Bending stress (sigma) is proportional to the square of height for a rectangular section in bending.
 

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Hardness testing on sheet material is iffy at best. Once a sample is too thin, you cannot test to ASTM Standards.

Why not determine dislocation density via TEM, and evaluate residual stresses by X-ray diffraction?
Yep, Brinell or Rockwell won't give you meaningful results on sheet metal. I've had some success using MicroVickers, but the problem there is that the usual sources of alloy data won't have MicroVickers hardness tabulated. Now if you are just doing a straight comparison of one to the next, MicroVickers would give you comparative data to say which one probably has a higher yield strength.

Of course since we're talking about a purely hypothetical situation here anyway, why not just cut five tensile test specimens from each of the two saxophones and get a direct comparison of yield strength?
 

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you forgot the extreme fiber distance (c) from the moment axis:

Stress = Mc/I

I = bh^3/12, b = base width, h equals height and strong axis dimension

c = h/2

substitute and solve:

sigma = M *(h/2) / (bh^3/12) = M*12/(2*b*h^2) = 6M/bh^2

Bending stress (sigma) is proportional to the square of height for a rectangular section in bending.
Yes, you're right. I HATE it when I don't remember something correctly, especially something so dumb. Like so many, I've gotten used to relying on the computer (ANSYS) to think for me. Haven't calculated stress in a beam manually in years. Not good.
 

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Yep, Brinell or Rockwell won't give you meaningful results on sheet metal. I've had some success using MicroVickers, but the problem there is that the usual sources of alloy data won't have MicroVickers hardness tabulated. Now if you are just doing a straight comparison of one to the next, MicroVickers would give you comparative data to say which one probably has a higher yield strength.

Of course since we're talking about a purely hypothetical situation here anyway, why not just cut five tensile test specimens from each of the two saxophones and get a direct comparison of yield strength?
Funny that you mention that. Several years ago, and colleague and I considered that. We had to test some FCC metals that were in a non-flat condition. As it turned out, it is not so simple if you want high precision measurements. The very act of cutting samples and flattening them to make tensile samples induces work hardening.
 

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Yes, you're right. I HATE it when I don't remember something correctly, especially something so dumb. Like so many, I've gotten used to relying on the computer (ANSYS) to think for me. Haven't calculated stress in a beam manually in years. Not good.
Well you had me guessing. I had to reconstruct 6M/bh^2, to make sure I recalled that correctly. Plus, one of my walk-around bits is increased section height nets a square in stress reduction - we are constantly battling weight/strength in my business.

But back to sax metal, all the brass alloys used should have a similar modulus, E. Or, same stiffness for the same thickness. Best way to increase or reduce stiffness, is to increase or reduce thickness.

Separately, the "softness" is really our intuition telling us some alloys bend with less force than others. Less intuitive, is that the same alloy can bend with more or less force, thanks to heat treatments, aging, etc.

Hardness is a decent rough indicator of the alloys yield strength. Yield strength is what is synonymous with "softness". Annealed carbon steel can yield at a few ksi, or hundreds of ksi - same alloy, just different depending on the heat treatment.

So you cant flex a piece of brass between the fingers and judge the "softness" or yield strength. Or hardness for that matter. But you can flex a key rod with your fingers, and determine if its thinner/thicker, more flexible. You still don't know (without bending it, yikes) if its "soft" or ductile with a low yield strength.

Lots of good discussion on this. I'm pretty pumped folks are interested in this stuff, its rare I have any discussion like this outside the office.
 

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Well you had me guessing. I had to reconstruct 6M/bh^2, to make sure I recalled that correctly. Plus, one of my walk-around bits is increased section height nets a square in stress reduction - we are constantly battling weight/strength in my business.

But back to sax metal, all the brass alloys used should have a similar modulus, E. Or, same stiffness for the same thickness. Best way to increase or reduce stiffness, is to increase or reduce thickness.

Separately, the "softness" is really our intuition telling us some alloys bend with less force than others. Less intuitive, is that the same alloy can bend with more or less force, thanks to heat treatments, aging, etc.

Hardness is a decent rough indicator of the alloys yield strength. Yield strength is what is synonymous with "softness". Annealed carbon steel can yield at a few ksi, or hundreds of ksi - same alloy, just different depending on the heat treatment.

So you cant flex a piece of brass between the fingers and judge the "softness" or yield strength. Or hardness for that matter. But you can flex a key rod with your fingers, and determine if its thinner/thicker, more flexible. You still don't know (without bending it, yikes) if its "soft" or ductile with a low yield strength.

Lots of good discussion on this. I'm pretty pumped folks are interested in this stuff, its rare I have any discussion like this outside the office.
Right now I am not working on this but until about a year ago I was involved in chassis designs for data center servers. Weight wasn't the issue but increasing sheet metal thickness from 1mm to 1.6mm vs. adding ribs to counter sag in a design where we were fighting for every 1/10 of a mm ... I actually enjoyed the math and running the simulations (and the BS that some folks threw at me :) )
 

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I have a question about how to handle the extra keys found on some vintage horns like the G# trill and fork Eb. What's the consensus on what to do with these keys:

1. Ignore them
2. Learn to use them
3. Modify them so they no longer function
 

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I have a question about how to handle the extra keys found on some vintage horns like the G# trill and fork Eb. What's the consensus on what to do with these keys:

1. Ignore them
2. Learn to use them
3. Modify them so they no longer function
I would learn to use them, and if they proved a positive outcome, I would continue to incorporate them in my technique. Otherwise, I would ignore them.

This would be an interesting poll.
 

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I would learn to use them, and if they proved a positive outcome, I would continue to incorporate them in my technique. Otherwise, I would ignore them.

This would be an interesting poll.
Indeed - I tried, but found I just didn't use the extra keys on my Conn NWII, I reversed the spring on the one I could just to rule out possible leaks on a never used key.
 

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I have a Buescher alto, made between 1935 and 1941 (it is a stencil, so I don't know the exact year) which is the most comfortable horn that I have ever played, and it sounds great. I like it better than my other alto, a Yamaha 62 purple logo in mint condition. The Yamaha is really nice, but I like the Buescher better. I have 3 tenors, Yamaha 62 generation 1, 1938 Conn stencil and 1954 Buescher aristocrat. I like the feel of the two older horns better than the Yamaha. Again, the Yamaha is really nice, but I like the older horns better. For me, the Conn is the most comfortable, but I always am more satisfied playing the Buescher.
 

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Modern horn keywork usually makes me feel like I'm being micro-managed and the horn is demanding that I have my fingers and hands in a specific position that I just don't like. Vintage horns, to me, are a little more "generic" in the sense that they feel more welcoming to different hand and finger positions and angles.
 

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Modern horn keywork usually makes me feel like I'm being micro-managed and the horn is demanding that I have my fingers and hands in a specific position that I just don't like. Vintage horns, to me, are a little more "generic" in the sense that they feel more welcoming to different hand and finger positions and angles.
That is interesting. Do you think it is because of the shape of the thumb hook and height of the palm keys? Perhaps more deeply dished (vs worn) pearls? I don't recall noticing such a thing when switching between vintage and modern horns, but I likely play different modern horns than you.
 

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Modern horn keywork usually makes me feel like I'm being micro-managed and the horn is demanding that I have my fingers and hands in a specific position that I just don't like. Vintage horns, to me, are a little more "generic" in the sense that they feel more welcoming to different hand and finger positions and angles.
The horn is demanding that your hands and fingers be in a specific position? I think that's true for all horns whether or not they're new or modern. As far as I know there is very little adjustment to the keys on the saxophone and most of those that do have some are modern. I sold most of my vintage horns and up-graded to modern. The only two I have left I couldn't get what I wanted for them, so I kept them. One is a Selmer Largebore alto the other is a Buescher Aristocrat tenor. What I can tell you is that when I was playing them regularly I didn't really notice just how bad their ergos were. Since I've been playing Cannonball and Yamahas I feel totally uncomfortable playing the vintage stuff. Not so much with the modern stuff, I adapted to them right away.
 
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