Re: [Harp-L] The reed issue

[Zombor Kovacs <zrkovacs@xxxxxxxxx>]

Maybe it was not clear to everybody.

Fatigue limit is the stress at which the part (in our
case a reed) will not break after an infinite numer of
bending cycles. So in case of a certain reed material
and thickness the maximum stress occuring during the
vibration of the reed does not exceed the fatique
limit ( a certain stress) it will never break. This
goes for steel and titanium alloys for example. But
not for copper alloys. They will break after a finite
numer of cycles no matter how low the stress is. This
is the theory. However one of the practical things is
that the grinding marks in the reeds will definitely
shorten reed life, this is the reason why people try
polishing them (not the factory because of sales
figures). 

THis is certainly my private opinion. 



--- Joe and Cass Leone <leone@xxxxxxxx> wrote:

> I find the following: flexing wire
> aluminum...... ridiculously low number of bends (6
> to 10). Alum is  
> best used in sheets where the load can be spread
> over a flat surface.  
> Modulus of elasticity is poor. Not good for
> trailers, cars, trucks or  
> vehicles where sudden shock is put on it (especially
> at the welds).  
> Best used in aircraft.
> 
> brass...... very maleable. (20-25 bends) Older
> plumbing is red brass  
> (good stuff). Newer plumbing is yellow (naval) and
> still decent.  
> Modern brass has too much recycled scrap in it.
> 
> bronze....... same as alum. Fairly brittle. 6 bends
> (at most)
> 
> mild steel.....10-15 bends. Not as maleable as
> brass.
> 
> stainless.......15-19 bends. (If not hardened)
> 
> copper........more than 25 bends.
> 
> silver........more than 15 bends
> 
> disclaimer. Naturally, there are in infinite number
> of alloys  
> available today. This makes our search
> overwhealming. This plethora  
> of alloys also complicates things as it tends to get
> into all the  
> other metals in amounts anywhere from trace to much.
> 
> Suffices to say that ANY spring material will work
> as a reed. (Even  
> bamboo, plastics, celluloids, carbon fibre, glass
> fibre, bone). I  
> (personally) feel that a copper berrylium silver 
> alloy (Silcober)  
> would do it.
> 
> smo-joe
> 
> 
> 
> On Mar 24, 2007, at 11:59 AM, Zombor Kovacs wrote:
> 
> > I don't have much experience with Hohner, but
> others
> > will tell us about their experience.
> > How much has Hohner invested in investigating reed
> > fatigue? As it is known copper does not have a
> fatigue
> > limit. It will fail after a number of cycles
> anyway.
> > Below the fatique limit steel and titanium alloys
> will
> > theoretically not fail after an infinite number of
> > cycles. Certainly a harp which never fails is no
> > business for Hohner (nor for others), no matter at
> > what price it is sold.
> >
> >
> > --- Fernando Bresslau <fernando@xxxxxxxxxxxxxxx>
> > wrote:
> >
> >> The balance that we try to keep at Hohner is
> between
> >> tone and
> >> durability. We want to have both, good tone and
> long
> >> life expectancy.
> >> From our experience, you don't get both at the
> same
> >> time.
> >> A harmonica with short life expectancy gives the
> >> opportunity to the
> >> customer to change brands, and we don't want
> that.
> >> In any case, nobody at Hohner believes that
> >> harmonicas which go south
> >> faster will increase sales.
> >> We have assembled and I have played harmonicas
> with
> >> SS reeds. They
> >> sound just fine and play well. But the
> manufacturing
> >> process is much
> >> more complicated and we don't have reasons to
> >> believe that reeds will
> >> last much longer. The Harmonetta had SS reeds and
> >> had issues with
> >> durability.
> >> But Hohner continuosly tries new materials out,
> and
> >> we are already
> >> clearly at a better performance/tone point than
> we
> >> were in the 80s or
> >> even the 90s.
> >> Other manufacturers are making interesting
> >> experiences. We are curious
> >> to see what results they get, and are open to new
> >> ideas.
> >>
> >> Cheers,
> >> Fernando
> >>
> >
> >
> >
> >
> >
>
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> 



 
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