I would expect the regular grip to not fail, as you tested, because it is rated
at 100% of 1/4 inch EHS breaking strength. Normally companies will not rate it
that way without a huge safety margin.
The somewhat longer "big grip" styles, according to PLP, were only for added
protection in cases where the guy lines had twisting or unwrapping issues. It
was never even available in 1/4 inch until tower companies started selling it.
The real danger is in doing things seriously wrong, like putting the loop over
something with inadequate radius. I've seen some pretty poor installations.
Some installers slip the loop over the tower leg, or worse yet, over the leg
plus a brace rod end. The rod puts a real sharp bump against the grip.
----- Original Message -----
From: Wayne Kline
To: Carl ; JI Charles ; low bad reflector
Sent: Friday, September 05, 2014 1:16 PM
Subject: RE: Topband: WTB: Guy wire stuff
Just my .02
Some call them Tomatoes some call them Tomottos
but even those fruits come in different size and texture .
When I built my station @ this QTH 4 guyed towers with broken up guys 502
insulators and
a PRE Formed guy Fasteners . A fellow FRC member had a source for 5000' rolls
of 1/4 Strand and 502 insulators
and these GUY grips that are used in the Cable industry... from pole to
pole to support the cable.
These grips had the 4 twisted wire with yellow tag
I had access to the Quality Control Lab @ the Mack Trucks test lab,
We first tested Rohn 1/4 EHS. to facilitate the pull I installed 3 Press
furls on each end
all test were repeated 2X
The EHS began to stretch twist and fracture @ 9K and fail @ 10.2K lb pull
Rohn PLP BIG GRIP (5) strand , with a length of 1/4 EHS and the same furl
at the end
never failed with the EHS stretching and failing at 11 +
K lb pull
now the Shorter 4 strand twist yellow tagged with the same length EHS ( 16"
exposed if my memory serves me )
This to never Failed and the 1/4 EHS both times
failing .
We painted layout dye on the 1/4 ehs/grip ends looking for pull out NONE
was found on either DEAD END
the guy grip loop end was around a solid 1 .250 rod to mimic a 502 or Rohn
tower leg or HD thimble.
I tried Thimbles but the press destroyed them in the clamp down securing
phase .
Conclusion .... 4 towers 180 plus guy grips All 4 strand DEAD End type
and 25 years and all A - OK... I even caught a lower level guy on my ROPS
bolt on my BIG tractor
pulling so hard till I got to stop it Ripped the joint open and bent it 70
degree on ROHN 25 !!!!
AND DID NOT FAIL..... It's length was 73' with two 502's attached directly to
the tower leg and three way equalizer plate.
MY .02
> From: km1h@jeremy.mv.com
> To: w8ji@w8ji.com; topband@contesting.com
> Date: Fri, 5 Sep 2014 10:46:37 -0400
> Subject: Re: Topband: WTB: Guy wire stuff
>
> > Preform comes from the name of a major grip manufacturer, not from "tower
> > apes".
> > http://www.preformed.com/
>
> ** Which has never been denied by anyone in this discussion. OTOH linemen
> and other strand installers use it as a general description thus my tower
> ape terminology.
>
> >
> >
> > Dead end is the termination style of grip.
> >
http://www.preformed.com/index.php?option=com_phocadownload&view=category&id=15&Itemid=145
> >
>
> ** Also previously discussed
>
> >
> > The normal "Guy Grip dead end" is typically used on any shorter length
guy
> > line that does not have rotational or twisting forces, and they are
> > normally are rated at 100% of stand breaking strength (but you should
> > check the catalog specs because some are less).
>
> ** As are the Big Grips rated at strand strength.
>
>
> >
> > The "Big Grip dead end" is the Prefomed Line Products name for the longer
> > grips, and are better for longer guy runs that might twist.
> >
> > PLP manufactures custom grips that are not cataloged. PLP would probably
> > be a better place for application advice than Ham tower parts vendors
(who
> > sell some pretty sketchy stuff at times) or Ham reflectors. :)
>
>
> ** PLP marketing is aimed at commercial and industrial applications and not
> hobbiests. Their idea of a radio tower starts where most ham versions let
> off.
>
>
>
> > Every tower failure I have seen has come from incorrectly installed guy
> > strand, saddle clamps, or anchors. I've seen towers where people splice
> > guy lines with dead ends looped through dead ends!
>
>
> ** Ive even seen some with RatShak guy wire which is maybe 1/8. Ive never
> used an inline splice either.
>
>
> It's common to see someone
> > worry enough to buy extra long grips (which doesn't do much for
strength),
> > > and then not worry about radius inside the loop (which just kills the
> > strength).
>
>
> ** Good points
>
> Carl
> KM1H
>
>
> >
> >
> > _________________
> > Topband Reflector Archives - http://www.contesting.com/_topband
> >
> >
> > -----
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> >
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
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