Re: ATM "Tuning" a wire spider?

["Jim Miller" <jim@jtmiller.com>]

Hi Dwight

I took the suggestion of someone (whose name I forgot...) to determine the
tension by comparison to a "one string guitar" which I made of some scraps
of aluminum angle, a piece of the same string I'm using on the scope of the
same length and a 50lb fishing scale.

Note that I'm not trying to do anything but stay a safe distance under the
rated strength of the line which is 50lb test.

Simple, works great.

have fun

jtm

----- Original Message -----
From: "Dwight K. Elvey" <dwightk.elvey@amd.com>
To: <atm@shore.net>
Sent: Monday, August 19, 2002 9:47 AM
Subject: Re: ATM "Tuning" a wire spider?



Hi
 Because frequency is vary dependent on wire length, why not
make a simple tension gauge. I have one I use on my sailboat.
It isn't complicated. You take a span of the wire and push
it from the side ( perpendicular ). The amount of tension is a
simple vector calculation of the amount that you can push the
wire sideways and the amount of pressure used to push sideways.
The effect of measuring does change the tension a small amount
but if the span is large and the deflection is small, it will
be quite small. Still, it will be quite consistent.
Dwight


>From: MLThiebaux <mlt@ns.sympatico.ca>
>
>
>At 06:27 PM 8/18/2002 -0700, Jim Miller wrote:
>>
>>Anyone have some references as to how to determine the tension on a wire
>>spider by measuring its note as it's plucked? I was hoping it might be a
>>simple function of length and tension...
>>
>
>The fundamental frequency  f (in cycles per second) of a stretched string
can
be found in physics textbooks:
>
> f = sqrt(T/m)/(2L)
>
>or    T = m(2Lf)^2
>
>where T is the tension (force), m is the mass per unit length, and L is the
length.  Let me know if you need help with units.
>
>Martial Thiebaux
>Rawdon Hills, Nova Scotia
>
>
>