[pianotech] Breaking bass string

[Delwin D Fandrich]

It could also be that wire--generally--is tougher than it is given credit
for. The formula commonly used by scaling and/or rescaling programs is one
popularized by Al Sanderson and it is significantly conservative. I'm not
sure what wire specifications he based it on but it gives a % of breaking
strength that is considerably below that of actual test with both Roslau and
Mapes IG wire. 

Both of these wires will take a 52 to 56 mm speaking length at C-88 without
causing much trouble. Obviously, 52 to 54 mm is going to be safer and, like
you, I wonder if those extra couple of mm actually translate into any
improvement in tone quality. 

When I say there hasn't been a lot of string breakage I speak, not just for
myself, but for the industry generally. I've been involved with enough
companies producing pianos with treble sections like this that I would be
aware of any significant warranty issues with breaking strings. I've also
come in contact with enough technicians of all skill levels around the world
that I think I'd be aware if this were an endemic problem. 

The only specific piano I know of that does have a consistent problem with
treble string breakage is the U.S. built Steinway S but with this piano I've
measured speaking lengths at C-88 upwards of 58 mm. And I've heard reports
of speaking lengths well upwards of 60 mm. That's when technicians call me
to ask if they are doing something wrong--they can't tune the things to
pitch. New wire helps for a couple of years but that's about it. Yes,
strings are going to break. 

ddf

Delwin D Fandrich
Piano Design & Fabrication
6939 Foothill Court SW, Olympia, Washington 98512 USA
Phone  360.515.0119 — Cell  360.388.6525
del at fandrichpiano.com — ddfandrich at gmail.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of John Delacour
Sent: Monday, April 11, 2011 1:12 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Breaking bass string

At 15:29 -0700 10/04/2011, Delwin D Fandrich wrote:

>Over the past 5 to 7 decades there have been quite a few pianos built 
>with speaking lengths at C-88 between 52 and 54 mm. Quite a few of the 
>Japanese pianos have come with C-88 speaking lengths of 55 and 56 mm. 
>Aside from those pianos using excessively dense and massive hammers 
>there hasn't been a lot of string breakage.

It could be that the Japanese wire is stronger at least in these sizes;  I
have no idea, but surely the only question worth asking is, do these pianos
produce a better or a stronger sound in the high treble?  Then, you say
there hasn't been a lot of string breakage, but you are someone who is aware
of the dangers.  That can't be said for all tuners.  I wonder how much
string breakage there is under less careful hands.

Another question that I raised off-list with someone is whether the actual
tension required to bring these very short strings to pitch is less than the
calculated tension.  I'd like to test this one day.

JD