www.flyhouse.com: Have you ever thought about the difference between stop sleeves and compression sleeves? If you're in the rigging industry, they are standard items used on the job. What if you used wire rope that was powder coated? Would that make a difference? Flyhouse tested some scenarios to give you a better sense of what they are capable of doing.
3 comments:
As someone who did most of the rigging in their high school theatre, I find this super interesting. It just goes to show that you can't always the rating of the equipment given by the manufacturer, and should always take precautions. This could also be super unsafe if a you were using a stop sleeve in a scenario assuming it was as strong as it was rated for, and the setup failed because of the stop sleeves. I would be interested to see the Break-o-matic test oval sleeves and even crosbys, to see if the strength they are rated to is accurate.
I knew stop sleeves were no where near as strong as oval sleeves, but seeing the test is way more striking than just talking about it. I was surprised that the powder coated cable did worse but only in that it did so much worse than the original estimate of 50% of the strength of the whole cable. With Ragtime we did encounter the difference between black and silver cable with their innate friction being different. Because of that layer of coating between the stop sleeve and the wire of the cable, it makes sense that it would fail first because there is another substance there. It’s like coating your hand with soap when a ring won’t come off except on a much larger scale. I think of this because of the way the two cables failed differently. The black cable pulled all the way through while the silver cable just frayed at the end and you could hear the snapping of the wires, but it didn't come apart.
That was probably one of the most concise rigging videos I have ever seen in my life. Not that I have been following Chicago Flyhouse’s Blog videos, but I have to say I really like how simple and to the point the videos are. I was also surprised at the lack of efficiency provided by the stop sleeves. I knew that they were not the most reliable termination regarding tension and other stresses, but I didn’t expect the result to be under 50 percent of the cable’s ultimate breaking strength. Another surprise was the effect powder coating had on the effectiveness of the stop sleeve, and I’m wondering what part of powder coat’s composition makes it that much less effective than plain steel cable. My one thought on the topic is that the powder coating smoothes over some of the surface area/roughness of the actual wire rope and allows more slippage.
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