[CAUT] Hardness of termination vs string breakage (was Re: restrung D)

[Fred Sturm]

On 4/17/07 3:56 PM, "RicB" <ricb at pianostemmer.no> wrote:

> You make the point that there is little or no movement at the bridge
> pin, hence you discard the friction moment and look at hardness alone.
> How then do nicks occur in bridge pins in the first place ?  I guess my
> point is that /whatever/ causes these knicks and grooves would tend to
> cause them in the string instead if the pin was significantly harder
> then the string. 
Hi Ric,
    I accept Ron Nossaman's analysis: bridge expansion and contraction
pushing the string up and down the bridge pin are the main factors in bridge
pin wear. Considerably more friction (between pin and string) is involved in
this motion than in strings being drawn through/past the pins in tuning. I
also accept the notion that there is simply too much friction at the bridge
for wire to slip past both pins and bridge top except when there is a very
large change in pitch (in the 100 cent range), based on experience,
experimentation, and the experiments and analysis of others. Now I guess it
is possible that friction between string and pin caused by bridge rise and
fall would cause wear to the string, if the pin were harder than the string.
Would it be significant, and enough to cause weakening leading to breakage?
I'm skeptical, but I guess I allow it is possible. It wouldn't keep me up
nights <G>. I have never seen a string break at a bridge pin, unless it was
water/rust related.
    About the question of capo hardening, I am merely asking people to set
aside "what seems reasonable" and "what one heard somewhere" and take a
fresh look. Is there really compelling evidence out there, one way or the
other? Is the conceptual model really convincing? The conceptual model
doesn't convince me, unless someone has a different one to offer, and I am
not convinced by what experimental evidence I have been able to gather from
people with experience.
    I have never fooled with capo hardening, nor has anyone in my neck of
the woods, so I have no personal experience to draw on. And no particular
axe to grind, either. It's just an annoying bit of cognitive dissonance I'd
like to see cleared up, or at least made a bit clearer.
Regards,
Fred Sturm
University of New Mexico