At 08:46 AM 8/8/2005, you wrote:
>Comparing a link of approximately 1/4 inch OD Fiberglass
>guyline (probably Phillystran) to 1/4 inch EHS steel, both
>in series so they have exactly the same tension, I measure:
>
>30 on gauge scale with EHS
>20 on gauge scale with Fiberglass
>
>33 EHS
>23 Fiber
>
>35 EHS
>25 fiber
>
>The scale on the PT-2 Loos gauge appears to move by
>somewhere about the square root of the tension increase
>(actually a bit more).
>
>30 translates to about 680 pounds tension.
>20 translates to about 300 pounds tension (if it
>extrapolates that far)
>
>Hardly the same, which makes sense looking at how the Loos
>gauge works. It is indeed very material sensitive with
>harder or stiffer material reading higher at the same
>tension, which makes sense also when you think of how the
>gauge works.
>
>73 Tom
Thanks, Tom--
Pretty much what I figured, and saves me the hassle of doing the tests.
Even saves me the hassle of finding my Loos. Confirms that nothing beats
my Dillon series dynamometer!
But this does allow one to make a calibration scale for a different material.
Just put some wire rope in series with the test material, confirm that the
reading on the wire rope is accurate and then take a reading on the new
material and get a correction factor for the specific material. Only issue
then is whether 1x7 EHS is orientation specific, if it has an inherent "set"
or bias or bend.
BTW I got my Dillon series dynamometer at a garage sale for $5, complete
with its carrying case and two clevises.
--John W0UN
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