[TowerTalk] Cable working load/breaking strength...///

[Bill Winkis]

*Here is what the folks at Amtec are saying... I use there cable grips...
*

*The broad application of AMTEC Grips on a wide variety of objects 
requires that adequate safety factors be used to establish a safe 
working load. The ratio of the listed approximate breaking strength to 
the normal working load is the safety factor. As an example, a safety 
factor of ten (10) would then mean that the working load is established 
by dividing the catalog listed approximate breaking strength by ten 
(10), or it can be stated that the working load is 1/10 of the catalog 
listed approximate breaking strength.*

*Now read below....
*

>> *My blueprint of my LM70 clearly states that the pull/down cable shall be 
>> ..3/16..7X19 and have a WORKING LOAD of 1400 pounds....most cable sold 
>> advertise a BREAKING STRENGTH ... the best I have found is 4200 pounds....or a working load of 420 pounds..a far cry from the 1400 pounds asked for on my print...
>>
>> As above....I am told the Working Load  is 1/10th of the Breaking Strength...
>>
>> If this is true ..where in the world can you find a 3/16 cable with a 
>> breaking strength of 14,000 pounds..???
>>
>> Or am I missing something....*

>> * -Bill*
>>     

>
>
> Maybe you're thinking of guy tensioning recommendations: 1/10th of rated 
> capacity?
>
> For a hoist application, the mfr may have different recommendations. 
> Engineering such things is a bit different (what design factors do you 
> use for where the cable runs over a sheave or pulley? what about dead 
> weight vs live weight.)
>
> Maybe LXC's directive is applicable here.. ask the mfr what they mean.
>
>
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