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## [TowerTalk] RE: ratings on wire rope

 To: [TowerTalk] RE: ratings on wire rope n2tk@earthlink.net (N2TK) Wed, 5 Sep 2001 18:53:22 -0400
 ```Oops. I made a mistake on the rating of the wire rope. According to the distributor it is rated at 7000 lbs. Breaking strength. I have recalculated the numbers below. Looking for comments if my margins are good or marginal. Tnx Tony -----Original Message----- From: N2TK [mailto:n2tk@earthlink.net] Sent: Monday, September 03, 2001 19:32 To: 'towertalk@contesting.com' Subject: ratings on wire rope I am using 1/4" wire rope to tilt over my tower. When my tower is near the ground I have a maximum pull of 2900 lbs. on the pulley. Since I am going through a single sheave on the gin pole from a winch, I assume that the maximum pull on the pulley is 2900/2 = 1450 lbs. I understand that 1/4" wire rope has a breaking strength of 7000 lbs. I have heard that you should take the breaking strength and divide it by 3.5 for the load rating - 7000/3.5 = 2000 lbs. I would think this would give me an okay safety rating?? Comments? However, one wire rope company told me that when you use cable clamps on the end of wire rope it reduces the strength by 20%. Was also told if you have the end of the wire rope "weaved" over a thimble, then strength of the wire rope is reduced by only 5%. Is this correct? If I am losing 20% strength of the wire rope then, 7000 x .8/3.5 = 1600 lbs. Is this cutting it too close? Comments please. If I have the cable company weave the end then, 7000 x .95/3.5 = 1900 lbs. Is either method sufficient, or should I be looking at 5/16" wire rope? 73 Tony N2TK List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems, Trylon Titan towers, coax, hardline and more. Also check out our self supporting towers up to 96 feet for under \$1500!! http://www.anwireless.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
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