Improperly swaged wirerope/ aircraft cables

Discussion in 'Scenery, Props, and Rigging' started by Dagger, Aug 23, 2019.

  1. Dagger

    Dagger Active Member

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    For example 1/8" wire rope with 1 sleeve and 1 crimp

    Or cables crimped " sideways"

    I refused to use them when it was provided.

    Was I too overcautious??

    Does anybody have an opinion ? Could it may have been used.? The object to be hanged -It was like well within breaking strength ( weight was ~ 300lbs. )

    My main concern was the improper crimping.

    Using thimbles or no make a difference??
     
    Last edited: Aug 23, 2019
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  2. egilson1

    egilson1 Well-Known Member Premium Member

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    I have a strong opinion on this. Your refusal to use it was correct. A single compression on a swage fitting is not going to hold even the working load limit based on a 5:1 design factor on breaking strength. This is assuming the tool you are using requires multiple compressions per fitting. It’s all about surface area and the coefficient of friction. Simply stated if it’s anything but what the manufacturer of the tool requires for number of compressions don’t use it.
     
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  3. Dagger

    Dagger Active Member

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    Crimped " sideways" as in the image (2nd image)
    Effect on the cable?
    I see lighting safetys crimped that way. Why?
     

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  4. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    A "crimp" done that way is WRONG. It is dangerous garbage and should be immediately destroyed. It is NOT appropriate for any use!

    Why do cables get made that way? Because the person making them has NO IDEA what they are doing.
     
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  5. danTt

    danTt Well-Known Member

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    I'm equally concerned with you hanging 300lbs on an 1/8" cable, unless I misunderstand your post.
     
  6. egilson1

    egilson1 Well-Known Member Premium Member

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    300lbs is fine on 1/8” if it’s a static sling and not running rigging. 2000lbs MBs with a 5:1 DF for a working load limit of 400lbs.
     
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  7. josh88

    josh88 Remarkably Tired. Fight Leukemia

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    Well 1/8" has a breaking strength of 2,000 pounds so a 5:1 factor is 400 which, or 200 for a 10:1. Seems within the range of acceptable for some uses.
     
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  8. Dagger

    Dagger Active Member

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    Does making a loop swage decreases the breaking strngth if 2000lbs?

    And the jumber of crimps also are factor? And using thimbles in the loop necessary?
     
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  9. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Rather than suggest my interpretation could you clarify this statement?
     
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  10. egilson1

    egilson1 Well-Known Member Premium Member

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    Absolutely. It was late for me when I posted so I probably didn’t phrase that as well as I could have.

    By static sling I mean a wire rope assembly that is not being lengthened or shortened by being wrapped on a drum, OR is not being moved over a sheave.
     
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  11. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @egilson1 While we're chit-chatting; what're your thoughts if / when comparing the effects of winding aircraft cable onto spiral-cut drums versus yo-yo drums from the perspective of cable wear / cable damage / life expectancy aside from yo-yo drums inherent self-varying rates of travel which are often useful in automated vertical lift and land applications.
    Toodleoo!
    Ron Hebbard
     
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  12. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    So you would accept the 5:1 if it were attached to a counterweight batten for instance? My criteria is impact load, so a load attached to a batten that will fly requires an 8:1 design factor.
     
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  13. josh88

    josh88 Remarkably Tired. Fight Leukemia

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    I would think Ethan's stipulation of not being run over a sheave would include a headblock and then for that matter the loft blocks holding the batten. Those lines would want a higher design factor.

    But I believe you're saying using wire rope statically to "dead hang" something from a batten. In which case because it stays hung the way it is and isn't the bit that is moving, it would be acceptable.
     
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  14. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Still subject to impact load, even if it doesn't bend while going up and down. Just like a trim chain - 8:1. It's in the load path of a moving object. While manual impact load may be only 1.25 or so, motorized can be much more. I've seen bent head block beams - that was 400 fpm and around 3.5. to suggest the load could be hung from that at 5:1 seems to close
     
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  15. Dagger

    Dagger Active Member

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    Any difference in using wire rope clips or using crimped sleeves?

    What it is static but the wire rope gets wrapped around once ( or more ) around an object ( like pipes) ?
     
  16. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Yes. Besides the obvious properly installed swaged fittings are as strong as the wire rope. Clips automatically rexuces thestrength to 80 percent. Also from my experience is easier to properly use swages than clips. Just not easy to actually torque the nuts on a clip, but it can be done. Also easier to check a swage witha a go no go guage. Torque wrench is not as easy.

    If you have not done this, do not do it for the first time without a trained rigger to oversee and check your work. If youhave not done it, you don't know what you dont know.

    I dont see many reasons to wrap the wire rope around a pipe. First, to remove or change you have to cut it. Almost all connections are made between a thimble and a clip, clamp, chain, or other device.

    If overheads, this is not work to do your first time without eyes on supervision.
     
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  17. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @egilson1 and/ or @What Rigger?
    While we're veering along; if / when you pass a single length of aircraft cable over the ~1.875" O.D. of one horizontal length of 1.5" I.D. schedule 40 iron / steel (or aluminum for that matter) pipe and properly anchor BOTH ends of this single run of cable to two rated attachment points on one, common, load; does this qualify as two supporting runs of cable and double the cable's capacity or would this be incorrect since the cable is not secured to the supporting pipe and support would be totally lost were the single run of cable to break, or either of its two terminations fail??
    Toodleoo!
    Ron Hebbard
     
  18. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Like a trim chain, it is a double load path and does split the load between both legs.
     
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  19. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    The first trim chains I met were lengths of welded link chain with a rated snap hook on only one end which was intended to snap back into the chain.
    The next trim chains I met were lengths of welded link chain with a rated snap hook on one end and a ~2" diameter welded steel ring on the other. In this theatre they passed their trim chains over their system pipes and passed the end with the rated snap hook through the approximately 2" diameter welded steel ring choking the trim chain on the system pipe with the rated hook dangling down for attachment to their load.
    Sometimes they'd wrap the trim chain around a system pipe twice prior to choking it to effectively shorten its length.
    Sometimes they'd pass the rated snap hook through a crimped or swaged loop in an aircraft cable attached to a load and clip it back into itself as a method of varying the trim chain's length by, effectively, half link increments.
    @egilson1 and @What Rigger? Comments? Thoughts?? Peals of laughter??? Screams of horror / terror????
    Toodleoo!
    Ron Hebbard
     
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  20. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Typically today it's a 30" or so length of grade 30 or for those that agree with the chain manufactures, like I do "Grade 63 hardened alloy chain meeting OSHA requirements for sling usage OSHA 1910.184(e)(5)" with one end captive on the thimble at end of lift line and other end anchored to the thimble with a shackle. Double load path.
     
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