[TowerTalk] Phillystran Tension Gage

[Ken Alker]

As a follow-up to my below comment, it turns out that the Loos web page 
describing their 90 Model B non-professional gauge found at 
<https://loosnaples.com/product/tension-gauges/90-model-b/> states in bold, 
"Note: The intended use of this gauge is to be used on 302/304 1×19 
Stainless Steel cable in appropriate sizes. If used on other cable types, 
sizes and construction your reading would be consistent (repeatable) but 
pound tension values would differ from those listed on the label."

I then noticed that (not in bold) on the Professional Models page found at 
<https://loosnaples.com/product/tension-gauges/professional-models/>, that 
it states, "All readings are based on 302/304 1×19 S.S breaking strengths."

Finally, poking around more, I found these additional notes at 
<https://loosnaples.com/how-tos/tension-gauges/pt/>, "GAUGE MAY NOT READ 
"O" WHEN AT REST, AS THEY ARE CALIBRATED AT MIDRANGE OF TENSION.  ...  IF 
FLAT SPOTS APPEAR ON NYLON SPOOLS AFTER EXTENDED USE, ROTATE NYLON SPOOLS 
45°."

Ken

--On Sunday, July 25, 2021 1:04 PM -0700 Ken Alker <ka6ken at alker.net> wrote:

> 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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