Tom Rauch wrote:
>> When any wire or cable is tightened, it becomes more
>> rod-like. At that point it doesn't really make any
>> difference what the material is - it still exhibits
>> the same property - and deflection, which is what
>> you're measuring. If cables are the same size, they'll
>> read the same.
>>
>> I've even measured Phillystran with one (it'll only
>> measure the HPTG4000 - it's the only one that'll fit
>> into the mouth of the gauge).
>> You'll nootice that the Loos is about a foot long.
>> It's just measuring the deflection in whatever it's
>> attached to. I think there are just some simple physics
>> involved to measure the tension. The Loos gauge was
>> designed for sailboat rigging but measuring other cables
>> is no problem.
> I've been thinking about this and I don't see how any
> tension gauge that requires scale compensation for wire
> diameter could be immune to effects of wire stiffness.
>
> When I look at it, it appears to me the Loos tenisoon gauge
> actually measures bending of a tiny area of wire between the
> two nubs at one end with the long area just serving as a
> "reference point" for the bending between the two fixed nubs
> that are at one end.
>
> Or do I have that wrong?
>
> 73 Tom
Right, it's a measure of the force required to bend a wire
under a particular tension.
So there are two components of the 'resistance': that caused
by the tension, and that caused by the wire stiffness.
The wire stiffness remains constant. At low tensions, it
dominates. As the tension increases, becomes a smaller and
smaller percentage of the total. The question is what
percentage of the total at common (10%) pre-tensions?
I don't own the Loos gauge, but gather that:
1) The supplied chart or table does not give alternate
calibrations for different guy material.
2) The chart is calibrated for flexible cable (wire rope).
The larger gages I own have alternate calibrations, but
only for the overlapping guy size range (1/2" to 3/4")
where EHS is available in both 1x7 and 1x19 configurations.
I would think it might be useful for someone to actually
calibrate the Loos for 3/16" EHS at 400 lbs, and 1/4" EHS
at 600 lbs, and take away any doubt. I may pick one up
from Champion and do it. I should have one of these in my
kit anyway.
73,
Steve K8LX
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