Re: Crane Rigging & Knots in Them
Hey Mark, sorry if you thought I came across as arguing that last thing I would want to do on here is that, especially with you. Round slings also have a 5:1 design factor for their working capacity it's an industry standard for slings other than chain which are 4:1. (i just found that out tonite as well!) Allmarks video is sweet. It shows a well worn round sling with a max break strength of 42,000lbs which makes for a wll of 8400lbs the thing broke at 33,000lbs or 75 percent thats awesome if it where new it would have broke around 42,000. The new piece of 1/2" Amsteel with a 34,000lbs max break strength which was knotted broke at the knot at 15,000lbs pounds this is less than the 50 percent rule it actually should have parted at 17,000lbs I would have bet money on it. So if you didn't realize it already that 34,000lb capacity Amsteel when used at 5:1 realizing you are going to be knotting it is good for 3,000 lbs. or 20percent of where the one in the video broke at 15,000lbs. Thanks for the video Almark that was extremely useful, this was driving me crazy. Again sorry if anyone took my curiosity the wrong way. Another note I learned that if that old round sling in the test had ever exceeded it's lifting capacity by 10percent it would not work as a fair example and where Kbooms don't display wieghts of piks it might be fair to assume it had. It performed well for it's condition though, I was surprised.
Hey Mark, sorry if you thought I came across as arguing that last thing I would want to do on here is that, especially with you. Round slings also have a 5:1 design factor for their working capacity it's an industry standard for slings other than chain which are 4:1. (i just found that out tonite as well!) Allmarks video is sweet. It shows a well worn round sling with a max break strength of 42,000lbs which makes for a wll of 8400lbs the thing broke at 33,000lbs or 75 percent thats awesome if it where new it would have broke around 42,000. The new piece of 1/2" Amsteel with a 34,000lbs max break strength which was knotted broke at the knot at 15,000lbs pounds this is less than the 50 percent rule it actually should have parted at 17,000lbs I would have bet money on it. So if you didn't realize it already that 34,000lb capacity Amsteel when used at 5:1 realizing you are going to be knotting it is good for 3,000 lbs. or 20percent of where the one in the video broke at 15,000lbs. Thanks for the video Almark that was extremely useful, this was driving me crazy. Again sorry if anyone took my curiosity the wrong way. Another note I learned that if that old round sling in the test had ever exceeded it's lifting capacity by 10percent it would not work as a fair example and where Kbooms don't display wieghts of piks it might be fair to assume it had. It performed well for it's condition though, I was surprised.
