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

[RicB]

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
    --