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
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|