Hi Jan,

A hacksaw blade can become a very sensitive spring.  Other sources of 
good spring material are the recoil springs from lawn mower motors, or 
even smaller, the recoil spring from a tape measure.

You could calibrate horizontal beam deflection with the use of weights 
previously measured with your vertical  balance scale.  Install the beam 
for vertical measurement. Establish a fixed distance from the beam 
support for a calibrated displacement line which will become your 
scale.  Then place the previously measured weights on the beam and mark 
the deflected position of the beam.  One previously measured weight 
would  be enough but you could test for linearity and accuracy if more 
than one previously measured weight was used for calibration.

It sounds like an interesting project.   Good luck.

Roger



psn-l-digest-request@.............. wrote:

> <>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1 |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: force gauge/transducer
> From: Jan Froom 
> Date: Mon, 30 Jan 2006 12:12:21 -0800
> Anyone know of a simple... quick... force gauge or force transducer...
> 20 - 30 grams max with a resolution of .1 gram. that I could make or buy?
>
> I'm working on a wind tunnel for my grandson's science fair project and
> we need a way to measure the lift and drag.
> I can measure lift with a beam balance scale... but the drag is in a
> horizontal direction and because the force is so low, I hate using a
> pulley arrangement to change the direction from horizontal to vertical.
>
> Oh... and did I say cheap?
>
> I'd settle for a spring gauge if I could find a source... that's
> accurate at this low a force.
>
> Thanks.... Jan in Gilroy
>
>
>
>  
>
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