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Re: [TowerTalk] Installing Big Grips

To: towertalk@contesting.com, k4kyv@hotmail.com
Subject: Re: [TowerTalk] Installing Big Grips
From: K7LXC@aol.com
Date: Fri, 4 Aug 2006 22:30:23 EDT
List-post: <mailto:towertalk@contesting.com>
 
In a message dated 8/3/2006 9:38:11 P.M. Pacific Daylight Time,  
towertalk-request@contesting.com writes:

>  Now, I have just recently read for the first time on a  couple of websites 
that I ran across, that with the type 502 insulators I  used, you are 
supposed to begin wrapping the grips at the SECOND set of  paint marks, while 
with metal thimbles you begin at the first set of  marks.  When I assembled 
mine, I began the wrap at the first set of  paint marks, which seemed the  
obvious way to do it, and the assembly  appeared to have gone together 
perfectly.


    Well, not perfectly. The second set of overlap  marks are for when you're 
putting them over insulators. If you use the first  set, the angle of the 
Preforms is more acute and puts more strain on the grip  strands. 

>  It would seem that beginning the wrap at the  second  set of marks would 
leave short, spiraled   sections  of wire between the wrapping and the 
u-shaped section of wire that loops  through the insulator, which would have 
less strength than straight  unkinked wire, plus the pre-forms would be 
gripping a shorter length of  wire.  
 
    Well, you need to observe the LXC Prime Directive  to "DO what the 
manufacturer says" which is use the 2nd marks for insulators.  Unfortunately 
this 
information isn't widely disseminated or known to amateurs  so yours is a 
common 
mistake. Probably not fatal - but a mistake. 
 
>  Supposedly, utility pole guy grips are 
unsatisfactory for  tower use because they have slightly less length than the 
ones designed  for tower use.  
 
    Not supposedly, DEFINITELY unsatisfactory. The  Preformed grips are 
precision pieces of hardware and are only compatible with  specific cables. For 
3/16" wire rope there are 8 or so grades of cable and  they're all different; 
e.g. different OD, different lay, different number of  strands, etc. You can 
only 
use the grip for a particular cable - no  exceptions. 
 
>  Wouldn't beginning at the second marks defeat 
the  advantage of using the Big Grips?
 
    No. The factory knows best. 

>  I  also read on one website that with Big Grips the guy tension should be  
precisely set at the recommended 10 percent breaking strength of the guy  
wire, in this case 3/16" EHS, which would come out to 400 lbs if I recall  
correctly.  Not having a reliable tension gauge, I eyeballed mine,  
tightening each set of guys until each cable felt tight without excessive  
sag.

>  Maintaining the tension precisely at 10% would  require readjusting the 
tension  at least twice a year, since I have  noticed that during the coldest 
weather my guy wires tense up as the steel  contracts, and they noticeably 
loosen up during hot weather, as indicated  by the amount of sag and the feel 
of the cable.  I could see how too  much tension could pose a danger of 
slippage, but what kind of failure  could be caused by tensioning them at a 
little  less than 10%?
 

The tension on the guys that you mentioned  - 400# - is at 70 degrees F. The 
tension varies with the temperature so your  observations are correct but 
perhaps your tension isn't. A relatively cheap  and accurate way to measure 
your 
tension is with a Loos Tension Meter. They're  available from 
_www.championradio.com_ (http://www.championradio.com) . I know the  owner real 
well and 
they're a good company to do business with. I'll bet you a  nickel that your 
tension 
is either too high or too low. Without measuring it,  you're taking a wild 
guess. 

 
Cheers,
Steve     K7LXC
Champion Radio Products
Cell: 206-890-4188

 
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