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  1. #1
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    technical specs of amsteel

    I couldn't find anything on the forum about the recommended bend radius for amsteel.
    After a bit of digging, I came up with this paper from Samson:
    http://www.samsonrope.com/get.php?file=490
    In which they recommend that if amsteel is bent more than10 degrees over a surface that that surface should be no less than 3 times the diameter of the amsteel itself, and the say 4 times is better. There is some other interesting info in there too.

    Was doing some splicing lately, which causes thought about what I was working on which caused research...

    So 3 times 7/64 is 21/64, or rounded up slightly is 3/8".
    Just wondering if anyone had done the homework on this... I'm sure that the this has been covered but I couldn't find anything...

    Mark

  2. #2
    Senior Member GrizzlyAdams's Avatar
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    had not seen that before, excellent find, thanks for posting! The business about bending radius applies directly to the way we use fixed eyes.

    The section on working loads should be required reading for everyone who builds and uses suspensions using Amsteel or dynaglide.

    Another valuable tidbit...this stuff has memory.
    Synthetic fibers have a memory and retain the effects
    of being overloaded or shock loaded. A rope that has undergone
    shock loading can fail at a later time even though loaded within
    the working load range.
    good read...
    Grizz
    (alias ProfessorHammock on youtube)

  3. #3
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    i just wanted to say thanks, this helped with my toggle questions now i know i need a bigger toggle!

  4. #4
    hairbear's Avatar
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    Nice post ,very useful.

  5. #5

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    This causes me concern about my use of whoopie hooks. I have them in a locked brummel loop on the whoopies, then the hook goes over the continuous loop at the hammock. These are pretty sharp bends. What do y'all think. Has anyone tested for breaking strength?

  6. #6
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    I would wonder about that, the holes are pretty small in that thing, he must've used amsteel to test the 1000 pound break strength. I think the amsteel would hold no problems, you just want to make inspection of your whoopies a regular thing maybe with each take down or something. If you read that paper fully it shows you what to look for as far as wear and tear goes.

    I was just thinking about getting some whoopie hooks and dutch biners myself. I wonder if we could get some testimonials from people that have hung on their whoopie hooks for a long time. Maybe some pics of the line showing any if at all damage?

    Mark

  7. #7

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    Quote Originally Posted by Markusforreal View Post
    ...In which they recommend that if amsteel is bent more than 10 degrees over a surface that that surface should be no less than 3 times the diameter of the amsteel itself...
    Thanks...I have been looking for that for a year (now bookmarked in a way I can find it).

    I have posted that info before and thought about it as I see some of the hardware and "software" being used. I quit posting the "3 x diameter" recommendation when I could no longer find the source to refer to.

    It's one of the reasons I frequently advise posters to chamfer the edge of holes in hardware they run rope through (the other being to remove the cutting action of a sharp edge).

    While we frequently get by with a sharper bending radius, many hangers don't realize how much their "system" is derating the amsteel's strength.
    Last edited by gmcttr; 02-14-2013 at 09:00.

  8. #8
    Rain Man's Avatar
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    Quote Originally Posted by gmcttr View Post
    While we frequently get by with a sharper bending radius, many hangers don't realize how much their "system" is derating the amsteel's strength.
    Absolutely. Cavers tend to die when they do things with their gear that hammock hangers do. Thank goodness hammockers don't have as far to fall.

    It makes cavers aware that every bit of knot, splice, ring, 'biner, gear, sunlight, sand, stepping-on, wear-and-tear, "memory," (and the list goes on) weakens their line to the point of catastrophic failure.

    I'm amazed at some posts that suggest using lighter and lighter and worse, cheaper and cheaper, suspension parts, especially those never intended for such, as if human life and limb are cheaper than a couple of bucks or a fraction of an ounce. I think I've never gotten over the caution drilled into me from my caving days by a club that had just lost a member who died due to gear failure/mis-use of gear.

    Be safe. Knowledge is strength.

    Rain Man

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    "You can stand tall without standing on someone. You can be a victor without having victims." --Harriet Woods
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  9. #9
    Senior Member OneThing's Avatar
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    Dynamic & Static Loads

    I was reading some material in the laboratory (The Can) this morning. I found it interesting and wish I could find it online, but I'll type it here as I think it's has some very important information for hangers.

    The following is from Knot & Rope Supply Safety Guide.

    APPLYING A LOAD TO ROPE:
    When weight is applied to rope, many different factors come into play. These factors can exist in either a dynamic or static load.

    DYNAMIC LOADS: This applies to a load that imparts varying amounts of weight on the rope, for example, a load that drops or a load that swings. This movement can greatly increase the force put on a rope, in some cases 2 to 5 times the weight of the items. It is crucial that the correct type of rope is chosen for these applications.

    STATIC LOADS. This applies to a load that is a consistent weight on the trope. For example, a rope holding a single weighted item. Static loads can also be briefly subject to dynamic loads. Being ware of lifting or pulling factors is crucial to maintaining a safe working environment.


    I found it interesting, that the movement of swinging can increase the force by 2 to 5 times. Makes me think about all the moving I did when I 1st started hanging. Getting in, getting on the pad, moving around on the pad, and then getting in the sleeping bag.

    From the outside, I'm sure it looked like I was in a fight for my life with a bear. I guess we'll never see, "If this hammock is a rockin, don't come a knockin" decal on the side of it.

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