[pianotech] Breaking bass string

[John Delacour]

At 12:02 -0700 08/04/2011, Wally Scherer wrote:

>The F# that broke has a core diameter of .049" and an outside 
>(single wrapped) diameter of .165".
>
>The F below it has a core diameter of .050 and od of .173.
>
>The G above it has a core diameter of .049 and od of .146.
>
>So, the measurements seem like a suitable progression.
>
>I am guessing that when it was replaced before, the same 
>measurements were kept, which may have resulted in too high a 
>tension for that string, hence its breaking in the first place.

That is often the case, but you need to calculate whether it is or not.

>Maybe I should order one with the same core diameter, and an od of 
>around .160".
>
>Any other opinions?

For a gauge 22 core to enter the danger area requires a tension of 
about 325 lbs, which is pretty high.  To get that tension your F# 
would need to be 125 cm long.

How long is the speaking length?

You can calculate the tension here:

<http://pianomaker.co.uk/technical/string_formulae/>


JD