Re: [Harp-L] Brass vs Stainless Steel

["Vern Smith" <jevern@xxxxxxx>]

Visit my harmonica website www.Hands-Free-Chromatic.7p.com
----- Original Message ----- 
From: "lil Buddha" <ltlbuddha@xxxxxxxxx>
To: "Harp-l" <harp-l@xxxxxxxxxx>
Sent: Friday, September 05, 2008 8:17 AM
Subject: Re: [Harp-L] Brass vs Stainless Steel


> I am not a metallurgist, but from what I have read here is how it works;
> many metals exhibit the effects of cumulative stress, but steel does not.
> Meaning that brass and bronze WILL eventually fail with repeated load no
> matter how small the load. Steel, theoretically at least, will never fail 
> if
> loading is kept below a particular level.
>
> What am I missing?

Only the technical terms that would make your explanation less meaningful to 
most readers.
"Cumulative stress" = metal fatigue, the gradual propagation of tiny cracks 
that eventually lead to failure.
"Particular level" = fatigue limit.

Even in copper-alloy (brass and bronze), fatigue is non-linear;  i.e. if you 
reduce the stress level by 10%, you get more than a 10% increase in the 
number of cycles to failure.

As you point out, the properties of SS do support the expectation of much 
longer fatigue life.  Knowing harp players, I predict that more robust reeds 
will result in more stressful playing.  You can't win.   ;o)

Vern





> Of course, the key to reed longevity whatever the material is do not use
> excessive force.
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