On 11/8/2010 12:21 PM, Joe Giacobello, K2XX wrote:
> I had never used Phillystran before, but am currently using the light
> duty grade (1200 lb. tensile) for stabilizing a long aluminum tubing
> stinger atop an aluminum tower.
>
> Based on recommendations from the supplier and info from this forum, I
> used 1/8" (or 3/16"?)
3/16"
> cable clamps to secure the ends of the
> Phillystran. They had been in place for about a month when I undid one
> set to make some adjustments to the guy. I noticed that the clamps had
> compressed or made deep cuts in the the Phillystran so that it appeared
> that its strength was probably compromised.
Probably less than with wire rope. Remember there is a right way and a
wrong way for the clamps to be installed.
First, the compression is normal within reason. The Phillystran is at
least 2/3rds jacket with a small Kevlar core. The jacket and end caps
protect the Kevlar from moisture to which it is very sensitive. As long
as the compression is not over done it really takes place in the
jacket. The cable clamps go with the U-bolt on the dead side (side
with the end of the cable) and the flats on the load bearing side. It
takes 3 of the cable clamps about 2" to 3" apart. Use a nut driver and
just snug the nuts on the cable clamps.
Yes the cable calms do reduce the load bearing capability of the cable,
but not all that much with Phillystran.
I use a lot of the 1200# test Phillystran for odd jobs but go for at
least the 4000# test for most load bearing towers.
> When I reclamped the
> adjusted cable, I didn't tighten the clamps to the same degree as I had
> originally because of my concern for cutting into the cable. I'm
> wondering whether these cuts are normal
Cuts would not be normal, but I'm assuming you are referring to the
indentations caused by compression of the jacket and not actual cuts.
If they are cuts it's time to pitch the cable.
> and don't seriously reduce the
> strength of the installation or not?
The strength of Phillystran is in the Kevlar core, not the protective
jacket.
> Should I have used a torque wrench
> or similar to tighten the clamps?
>
It'd need to be a pretty small torque wrench as you only snug them with
a nut driver.
> Also, end caps were supplied for the cable. Are these merely decorative
> or do they serve some other function?
>
They are very important. Don't ever leave Phillystran outside where
moisture can collect without the end caps *sealed* on. If a coil of
Phillystran has been exposed to moisture without the end caps its
integrity is doubtful and lifetime seriously shortened. Those caps need
to be *sealed* on.
> I'd appreciate any info that the forum can provide.
If it's been exposed to moisture it's likely that within a year or two
the strength will only be a fraction of its original rating.
73
Roger (K8RI)
>
> 73, Joe
> K2XX
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