Re: [Harp-L] ...Why do reeds go out?

[Ryan Mitchell-Smith <music@xxxxxxxxxxxxxxxxxxxxxx>]

I always thought it was down to the acidic nature of our saliva... It 
eats away at the reeds over time.

On 19/05/2012 22:03, Joel Fritz wrote:
> I'm not sure if fatigue makes them go out of tune, but I was a heat 
> treater for nearly fifteen years.  Most every variety of brass is not 
> hardenable by heat treatment.  I'm assuming that the reeds are work 
> hardened by forming.  I'm just about positive the reeds aren't made 
> from beryllium copper, the most common heat treatable copper alloy.  
> IIRC you can retune a flat reed by shaving it.  Now I'm getting 
> curious if hardness (tensile strength) is a factor in the frequency of 
> something fixed at one end that vibrates.  From what I vaguely 
> remember from high school physics the variables are mass, length, and 
> tension.  It was a long time ago though.  :)
>
> On 5/19/2012 12:36 PM, Chuck Linville wrote:
> > Hey y'all, happy weekend. I've been getting my feet wet with harp 
> > repair and re-tuning. Been playing for a few short years, I'm a 
> > machinist by experience, and I've always been interested in opening 
> > these things up, but never made the time. Well, now I have the time 
> > (unemployment can do that) and I am just fascinated with these 
> > things! Anyway, this tuning business has really got me wondering; 
> > what exactly makes them go out of tune? I've got a box of old harps 
> > from a friend and I am going through them, mostly Special 20s. I've 
> > been able to correct some by cleaning them. Others look 
> > indistinguishable from a good reed and I can't do anything a thing to 
> > cheer them up. All the gaps look fine and the rivet is solid. The 
> > only other thing I can imagine is metal fatigue from having been 
> > vibrated a gazillion times. Am I right? Thanks in advance! -chuck  
> > (PS: If so, has anybody had success re-tempering?)