[TowerTalk] turnbuckle safety wires

[Roger (K8RI) on TT]

There is often a big difference between what is a proper turnbuckle 
installation and what the typical ham chooses and does.
Likewise, I've never seen a turnbuckle unscrewing by itself. Vandals?  
Kids?  All a safety wire would do is slow determined vandals down. There 
are other, quicker methods, but they leave no doubt that vandals did the 
deed.

I've seen a number of ham installations where a safety wire was needed 
in case the turnbuckle failed.  There is a hexagonal Aluminum rod, 
threaded on both ends (LH & RH threads). They are handy, easy to use, 
light weight, and cheap. I've even used some on small, single and double 
braided rope where the lines only serve as a backup to keep a vertical 
straight.  IOW, strength wasn't as important as light weight. However, I 
have seen these used on ROHN 25G. Where their failure could lead to 
expensive repairs and safety issues. The use of under size turnbuckles 
is common. In those cases the safety wire does serve as a "back up" in 
case the turnbuckle fails.   THOSE safety wires need a minimum of 2 and 
preferably 3 cable clamps at each end

In the case of the Al rods, they don't unscrew. The threads fail. The 
ends are steel rods with the typical, "ends bent in a circle" which is 
not welded or forged. The internal Al threads contacting steel corrode 
relatively fast.

As I've said before, the typical ham has nowhere near the knowledge 
present on TowerTalk and even that is going down rather quickly with 
today's question pool and the practical knowledge required to earn a 
license.

Towers seem to be a subject where the input of an "Elmer" is seldom 
sought.  The old TV tower approach with a soft, galvanized guy simply 
wrapped around a single tower leg, rather than a guy bracket (as ROHN 
uses).  Those old Radioshack guys are surprisingly weak.  I've seen 
three men pull a 3/16ths in two while walking up a 40' tower.

73, Roger (K8RI)


On 9/12/2017 Tuesday 8:48 PM, Steve Maki wrote:
> The typical turnbuckle safety wire is designed to prevent inadvertent 
> unscrewing of the turnbuckle, either from vibration or random 
> vandalism. It's not to support the tower in the event of a turnbuckle 
> failure. That would at least require more than one in-line cable clamp.
>
> Note: I've NEVER seen a turnbuckle prone to unscrewing itself, but 
> don't consider that a reason to not use them.
>
> The turnbuckle shouldn't be the weak link in the system anyway. It 
> should be oversized and of good quality to insure that the threads 
> remain in good operating condition.
>
> -Steve K8LX
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-- 

73

Roger (K8RI)


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