Bass string scaling question

[John Delacour]

At 7:08 am -0700 28/5/07, David Love wrote:

>I'm not sure I understand the problem with the 33/66 ratio.  Why does that
>create an interference?

By interference I mean that the lengthwise line drawn through the 
tops of the copper coils is wavy and not straight, giving the string 
a very queer look.  It would be interesting to be able to describe 
exactly what happens, but since I know it does happen I simply avoid 
the ratio.  Here's a guess : the frequency with which the peak of the 
top-cover coincides with the troughs in the under-cover causes a 
crushing or squeezing sideways of the inside coils so that the top 
coil forces itself closer to the core.  You might well say that they 
coincide fairly frequently with a 40/60 ratio, but the fact is that 
with this ratio the line of the string is acceptably smooth.

>Also, during the wrapping process, is there some elongation and therefore
>slight thinning of the copper wrapping such that you should build into your
>target outer diameter calculations some factor for that shrinkage, as it
>were.

Absolutely.  Say 10%.  It will vary according to the stringmaker and 
to a small degree, according to the copper gauge.  I made tables 
years ago for my odd string work and for sets I have a factor built 
in to the programme to allow for the stretch.  Thus I specify a 
"target tension" and the programme gives me the actual theoretical 
tension after factoring in the actual copper sizes available and the 
reduction in diameter due to stretch.

If I go on like this, I'll have the boys from the cabal round :-)

JD