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

[Alan McCoy]

Ric,

Would you mind quantifying "thin" and "sharp" for me? Ted Sambell talked
about a 2.5mm radius, which works out to 0.1" or between a sixteenth and an
eighth inch radius (for metric-phobes).

Thanks.

Alan


-- Alan McCoy, RPT
Eastern Washington University
amccoy at mail.ewu.edu
509-359-4627


> From: RicB <ricb at pianostemmer.no>
> Reply-To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Date: Fri, 20 Apr 2007 23:46:46 +0100
> To: <caut at ptg.org>
> Subject: [CAUT] Hardness of termination vs string breakage (was Re: restrung
> D)
> 
> String breakage at the capo is more complicated then just one bit.  I
> have a 9 foot Petrof under my care with the same feature (actually a
> pretty good one in my book as well...)  The <<soft>> capo sharpened will
> indeed groove over time... but if other issues such as speaking length
> of the string and counterbearing angle are compatible with the soft,
> sharp capo... then whatever trouble you have with string breakage must
> find its roots elsewhere.  I havent seen a broken string on this Petrof
> (strangely enough) for over 18 months except in the bass and agraffe
> sections... and its played hard 6 days a week 10 months of the year.
> Three quarter medium strike weights for what thats worth.
> 
> Each instrument is different to be sure, but by and large most whose
> experiences I have listened to through the years have reported fairly
> consisitently that thin, sharp, and soft works much better over time
> then wide round and soft.
> 
> Again... I suggest reading McMorrow for some interesting perspectives on
> exactly this subject matter.  I agree tho... the proof is in the
> pudding.  I've been handling capos as mentioned in earlier posts for
> well 25 years now... and have had ample opportunity and more to watch
> the results over time.  Petrofs and Bosies are not, definitely not
> proverbial high treble string breakers.  God knows Petrofs have problems
> they need working out... but this is not one of them.  Not in my
> experience anyways.
> 
> Cheers
> RicB
> 
> 
>     With all due respect. I had an experience several years ago with a
>     Bosendorfer grand which seems to contradict this. It continually broke
>     strings in the top section. Bosendorfer, and I believe Petrof have
>     retained
>     a feature found in early 19th. century pianos such as Streicher and
>     Erard,
>     namely, a removable treble capo bar. I removed this and found it to
>     have a
>     very sharp edge, and to be badly grooved, the edges of the grooves
>     still as
>     sharp as the unworn arears. The metal was quite soft , so I was able to
>     easily reshape it to the radius resembling that of a 2.5mm rod, and
>     polish
>     it. I then re-strung the section  (actually the two top sections)
>     and there
>     has never been a broken string since over many years. The piano is used
>     quite heavily by good pianists. Moreover, if anything, the tone was
>     better
>     than before. A vibrating string is quite evidently being stretched at
>     amplitude . and the consequent lengthening is offset by the alternating
>     termination point caused by the deflection of the wire around the
>     radius of
>     the bar. As is said, the proof of the pudding is in the eating.
> 
>     Ted Sambell---- Original Message -----
>     From: "RicB" <ricb at pianostemmer.no>
>     To: <caut at ptg.org>
>     Sent: Thursday, April 19, 2007 3:00 AM
>     Subject: [CAUT] Hardness of termination vs string breakage (was Re:
>     restrung
>     D)
> 
> 
>> 
>> It is a matter of all these things, including hardness. Really,
>     this kind
>> of goes without saying.  A soft sharp profile will wear and
>     groove, and it
>> will do so in a way that works out nicely over time.  A rounded soft
>> profile on the other hand will buzz like crazy with wear.  Dig out
>> McMorrows book for some good perspectives on it.
>> 
>> Fred,  there is friction at the bridge pin from something... this is
>> obvious because of the pins getting damaged over time. If the
>     metal of the
>> pin was significantly harder then the string... these same
>     moments would
>> still be at work and the wear and tear would be transfered to the
>     string
>> material.
>> I mean... why would we have any use for super hard abrasives like
>     diamond
>> files or any such thing unless the basic idea that harder vs softer
>> results in softer loosing ?
>> 
>> Cheers
>> RicB
>     -- 
>