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

[Joel Fritz <williemctell@xxxxxxxxx>]

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?)