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Old 12 September 2010, 16:21   #11
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I doubt very much that an 8mm shackle would take 6tonnes. Unless ANY form of lifting gear is marked with its SWL(Safe Working Load)& accompanied by a current test cert. Then for all intents & purposes it's junk, you pays your money & takes your chance
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Old 12 September 2010, 17:38   #12
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Quote:
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whats the test number of the shaclke
316 can you not see it.........
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Old 12 September 2010, 19:12   #13
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Dont know what the number refers to .. but the break doesnt look right for an overloading fail

and it doesnt look like a 6 tonne shackle either !




Can you post a pic of the bits ligned up so we can get a better idea of the way it failed ?
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Old 12 September 2010, 20:13   #14
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Quote:
Originally Posted by Pikey Dave View Post
I doubt very much that an 8mm shackle would take 6tonnes. Unless ANY form of lifting gear is marked with its SWL(Safe Working Load)& accompanied by a current test cert. Then for all intents & purposes it's junk, you pays your money & takes your chance
I doubt it as well. The stamped tested galvanised shackles we sell at work for 4x4 recovery are I think 3/4in pin size for 4.75 ton rating (though I think that is a lifting rating so actual breaking strength is much higher).

Looking around on google an 8mm s/s shackle might be rated at half a ton if you are lucky ... breaking strains around 2500kg seem to be quoted and lifting ratings are usually min 5x safety factor.
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Old 13 September 2010, 04:21   #15
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could the shackle have been used without the pin at sometime or perhaps been unscrewed or come undone then been put under load and not been noticed ,
looks to me like the number will be 316 kgs
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Old 13 September 2010, 04:34   #16
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Chewy is wrong!

Quote:
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316 can you not see it.........

Stupid me and all this time I thought 316 was a type of Stainless (A4?)

My point being is if the shackle was a proper one and had been load tested then it would have a test number stamped on it and there should be some comeback. If I remember correctly then Stainless doesn't have the load capacity of ordinary steel so it looks very small to me also.

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Old 13 September 2010, 05:06   #17
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perhaps the shackle dident have an even staight pull on it ,even more so if it was wrapped webbing strap,,eg crown to pin and it was loading sideways or at an angle that would lower the load limit ,if it had been pulling on an angle the shackle could have been springing back and forth on its self over time causing it to crack /fracture especially if the pin was not nipped up .
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Old 13 September 2010, 05:59   #18
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Quote:
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Chewy is wrong!




Stupid me and all this time I thought 316 was a type of Stainless (A4?)

My point being is if the shackle was a proper one and had been load tested then it would have a test number stamped on it and there should be some comeback. If I remember correctly then Stainless doesn't have the load capacity of ordinary steel so it looks very small to me also.

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Stu - are you suggesting that every shackle the leisure boater uses should be tested and certified? This shackle was being used in place of a hook on a trailer winch - not for some lifting operation. The original hook was probably not individually certified, nor I suspect will the bow eye it was connected to.

The OP doesn't seem to be looking for "comeback" he seems to be saying "wow this looked like the beefiest bit of my set up - its surprising that this was the point that failed - can anyone explain it? or suggest what I can do (within a sensible budget) to avoid its replacement going the same way"
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Old 13 September 2010, 06:17   #19
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Quote:
Originally Posted by m chappelow View Post
perhaps the shackle dident have an even staight pull on it ,even more so if it was wrapped webbing strap,,eg crown to pin and it was loading sideways or at an angle that would lower the load limit ,if it had been pulling on an angle the shackle could have been springing back and forth on its self over time causing it to crack /fracture especially if the pin was not nipped up .
that's probably a plausible explanation - SS is quite hard so I think it would suffer from fatigue failure if there was any flexing - shackles under load often don't sit straight unless the load on the pin is a flat strap so when a rope is pulling on it (or a bow eye...) it will probably sit slightly cock eyed
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Old 13 September 2010, 06:41   #20
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Well the leg that has snapped is the 'loose' side certainly, as opposed to the threaded side as it would appear in the pic
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