Re: [Harp-L] Fatigue and reed life

["Vern Smith" <jevern@xxxxxxx>]

----- Original Message ----- 
From: "Joe and Cass Leone" <leone@xxxxxxxx>
To: "David Payne" <dave@xxxxxxxxxxxxxxxxxxxxxx>
Cc: <harp-l@xxxxxxxxxx>
Sent: Thursday, April 17, 2008 10:07 PM
Subject: Re: [Harp-L] Fatigue and reed life


> On Apr 17, 2008, at 9:27 PM, David Payne wrote:
>
> > The Steel appears to me as virtually identical to brass reeds in 
> > thickness.

Because SS has a greater modulus of elasticity than copper alloy, it can be 
expected to be thinner where it flexes near the rivet.  Because SS has a 
lower density than copper alloy, it can be expected to be thicker at the 
tip.  If the SS reed is designed to have the same pitch and response to 
pressure as a copper alloy reed, then its geometry must be different. 
People in the past have made flat SS reeds and have then mistakenly drawn 
conclusions about the SS material.  The differences that they could perceive 
playing the harp were differences in reed design.

If SS and Cu-alloy reeds had the same shape,  the pitch of the SS reed would 
be very much higher because it would be both stiffer and lighter in weight.

Vern
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