[TowerTalk] Phillystran Tension Gage

[Ken Alker]

If my conclusions are correct, the chart appears to be based upon the 
breaking strength of a different type of wire than one would use for a 
tower.  The chart appears to be based upon stainless steel cable (for 
sailboats) rather than zinc coated cable (for towers).  The SS cable has a 
higher breaking strength, hence, using the Loos would mean one would 
over-tention the guys on a tower if using the % scale, rather than the LBS 
scale.

--On Sunday, July 25, 2021 3:49 PM -0400 john at kk9a.com wrote:

> Why are you concerned with the Loos gauge's breaking strength chart?  I
> just use the table to set the guy wires to the recommended tension
> (usually 10% of its breaking strength).
>
> John KK9A
>
>
>
> Ken Alker ka6ken wrote:
>
> I'm new to this, but did a lot of research and found that the Loos PT2
> appears to be calibrated for wire with a breaking strength of 4545-5000
> lbs, while the Rohn 3/16EHS500 wire has a breaking strength of 3990 lbs.
> I  assume, based on specs on various types of wire rope found at
> <http://www.wcwr.com/catalog/webcat.pdf>, that the Loos PT2 is calibrated
> more for 1x19 Stainless Steel type 304 wire rope used for sailboat
> rigging  (4700 lbs) rather than zinc coated 3/16EHS500 (3990 lbs).  Here
> is my math  based upon the chart found on the Loos gauge (from the web
> site quoted by  Tim, below):
>
>  LBS   %  LBS/%
> ----  --  -----
>  240   5  4800
>  300   6  5000
>  420   9  4666
>  500  11  4545
>  640  14  4571
>  840  18  4666
> 1030  22  4681
> 1240  26  4769
>
> In conclusion, perhaps one should pay more attention to the "LBS TENSION"
> portion of the Loos chart than the "% BREAK STRENGTH" if using the Loos
> for  3/16" EHS (assuming it deflects in the same way that the sailboat
> wire rope  deflects), or one may overtension their guys.  (Although,
> perhaps the error  when tensioning to 10% of breaking strength when
> tensioning to 400lbs, or  600lbs in the case of Phillstran, isn't big
> enough to worry about?)
>
> Even then, however, I'm very curious as to why the Loos numbers are all
> over the map (4545-5000) rather than consistent at one breaking strength;
> it is not just rounding error since their "LBS TENSION" appears to be
> +-10  lbs.
>
> Ken, KA6KEN
>
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