Ron,
Here's the information you're looking for (and more). Not every field in the
table is filled in. I've researched only the values of interest for my towers
and guying hardware. The values given are for forged
shackles and turnbuckles intended for tower guying. These values do
not apply to generic "hardware store" materials.
Working Load (pounds) Breaking Strength (pounds)
------------------------------- -------------------------------
Dia EHS Wire Shackle Turnbuckle EHS Wire Shackle Turnbuckle
--- -------- ------- ---------- -------- ------- ----------
1/4" 1330 1000 500 6740 5000 -
5/16" 2240 1650 - 11200 6600 -
3/8" 3080 2000 1040 15400 7500 6000
7/16" - 3300 - - 13300 -
1/2" 5380 4400 1960 - 17600 11000
5/8" - 6500 3180 - - 17500
For example, a 3/8 inch forged shackle and a 1/2 inch forged turnbuckle
should be used with 1/4 inch EHS guys to achieve 6740 pound breaking
strength for the guy system.
The breaking strength of a 1/4 inch EHS guy system will be reduced to
6600 pounds if 5/16 inch forged shackles are used, and 6000 pounds if
3/8 inch forged turnbuckles are used. Of course, in many cases the
reduced breaking strength is more than adequate.
For my 5/16 inch guy system rated at 11,000 pounds breaking strength,
I use 7/16 inch forged shackles and 1/2 inch forged turnbuckles.
73!
Frank
W3LPL
---- Original message ----
>Date: Wed, 25 Jul 2007 15:24:34 EDT
>From: TexasRF@aol.com
>Subject: Re: [TowerTalk] Rohn 45 Torque bars
>To: ron@k4wz.com, towertalk@contesting.com
>
>
>Ron, you are caught up in the Shackle working load vs guy cable breaking
>strength quandary. Typical breaking strength (actual number undocumented) is
>four to five times the working rating.
>
>If you accept this, then the 2000 lb rating of the shackle is sufficient.
>
>73,
>Gerald Williamson K5GW
>Texas Towers
>
>
>
>
> In a message dated 7/25/2007 2:17:41 P.M. Central Daylight Time,
>ron@k4wz.com writes:
>
>I am using Rohn 45 Torque bars and having trouble attaching the guy wire to
>the torque bar. I am using phillystran and using big grips. The big grips
>just goes through the torque arm 1/2 inch hole and thire is no room for a
>thimble.
>If I use a 3/8" Shackle they are rated only at 2,000 lbs. That dont seem
>enough. The Phillystran is rated at 6,700 lbs.
>
>What are your suggestions ?
>
>Ron
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
>
>
>
>************************************** Get a sneak peek of the all-new AOL at
>http://discover.aol.com/memed/aolcom30tour
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|