Swage v Cable clamps v verlock/griplock
- Thread starterDGotlieb
- Start date
What Rigger?
I'm so fly....I Neverland.
If we're going to discuss those options (and we might not, depending on the application), it would be super helpful to know what you're trying to accomplish and why you had to go to an internet forum to find this information. Point being, it's easy to get (and is probably in the brain) of your local competent rigger or TD.
Sooooo....help us out DG, whatcha got goin' on?
I have numbers in my head from the swage and cable clamps I wanted to double check them. Then I have heard about verlocks but don't have much info on them and was hoping the brain trust here would have a better faster responce then my Google Fu. The Document connect by Robert is exactly that type of thing I was hoping for thanks.
What Rigger?
I'm so fly....I Neverland.
Google-Fu! Yessssss!
Okay, don't forget that JR Clancy has lots of good stuff (and freebies) on their website and all manufacturers should have even more in depth answers.
And seriously- thanks for not being one of those folks that come back with "I want to put a person in the air, and I'm a rock climber and I think I can pull this off".
A couple of caveats before I start.
1) All hardware efficiency is based on proper installation. So for swags fittings that's correct number of compressions for the tool being used. For wire rope clips that's orientation and torque.
2) in the entertainment industry we predominantly use 2 design factors for wire rope. 5:1 for standing rigging (slings) and 8:1 for running rigging (lift lines that move over a sheave)
3) the proper way to determine the working load limit is the following equation. (Breaking Strength x termination efficiency) / design factor.
4) We are looking for the weakest link. Terminations are not compounding on the breaking strength. So a sling with a termination at either end would have a working load limit of whichever termination is the weakest.
5) the efficiencies I am going to give are the average of the popular manufacturers. You need to check the documentation on each piece of hardware you are specifically using.
Now for the rest of our story.
A properly installed stage fitting is 100% efficient. There is no strength reduction. So a wire rope with a breaking strength of 100lbs using copper swage fittings and thimbles to form a sling would have a working load limit of (100 x 1.0) / 5 = 20lbs.
Wire rope clips on average have a efficiency of 80%. Same for "fist grips".
Now VERlocks and Griplocks are different than other terminations in that they don't have an efficiency rating, but a Working load limit. For instance a griplock for 1/8" wire rope has a WLL of 250 ponds. The wire rope has a WLL of 400lbs when used as a sling with an 5:1 df and 250lbs when used as running rigging with a 8:1 df.
There are other options as well such as Flemish eyes or epoxy based terminations. You will usually see these in other industries such as telecommunications.
And then there is the famous Circus knot. More art than science.
Hope this helps muddy the waters.
Ethan
1) All hardware efficiency is based on proper installation. So for swags fittings that's correct number of compressions for the tool being used. For wire rope clips that's orientation and torque.
2) in the entertainment industry we predominantly use 2 design factors for wire rope. 5:1 for standing rigging (slings) and 8:1 for running rigging (lift lines that move over a sheave)
3) the proper way to determine the working load limit is the following equation. (Breaking Strength x termination efficiency) / design factor.
4) We are looking for the weakest link. Terminations are not compounding on the breaking strength. So a sling with a termination at either end would have a working load limit of whichever termination is the weakest.
5) the efficiencies I am going to give are the average of the popular manufacturers. You need to check the documentation on each piece of hardware you are specifically using.
Now for the rest of our story.
A properly installed stage fitting is 100% efficient. There is no strength reduction. So a wire rope with a breaking strength of 100lbs using copper swage fittings and thimbles to form a sling would have a working load limit of (100 x 1.0) / 5 = 20lbs.
Wire rope clips on average have a efficiency of 80%. Same for "fist grips".
Now VERlocks and Griplocks are different than other terminations in that they don't have an efficiency rating, but a Working load limit. For instance a griplock for 1/8" wire rope has a WLL of 250 ponds. The wire rope has a WLL of 400lbs when used as a sling with an 5:1 df and 250lbs when used as running rigging with a 8:1 df.
There are other options as well such as Flemish eyes or epoxy based terminations. You will usually see these in other industries such as telecommunications.
And then there is the famous Circus knot. More art than science.
Hope this helps muddy the waters.
Ethan
Thanks for the quick break down I have always worked with wire clips at 60% efficiency in my math. So I was wrong.... but in the correct direction If i was going to be wrong. I also do know the infamous circus knot but generally try to avoid it. I have been running low on supplies so have been debating if adding VERlocks/griplocks into my next order of rigging hardware would be a good idea. I had not worked with them in the past but I had been hearing and seeing them showing up in use elsewhere. I'm starting to think I may get some for rigging up portals that are dead hung, not fully converting away from swage and cable clips for our flying pieces.
A couple of caveats before I start.
1) All hardware efficiency is based on proper installation. So for swags fittings that's correct number of compressions for the tool being used. For wire rope clips that's orientation and torque.
2) in the entertainment industry we predominantly use 2 design factors for wire rope. 5:1 for standing rigging (slings) and 8:1 for running rigging (lift lines that move over a sheave)
3) the proper way to determine the working load limit is the following equation. (Breaking Strength x termination efficiency) / design factor.
4) We are looking for the weakest link. Terminations are not compounding on the breaking strength. So a sling with a termination at either end would have a working load limit of whichever termination is the weakest.
5) the efficiencies I am going to give are the average of the popular manufacturers. You need to check the documentation on each piece of hardware you are specifically using.
Now for the rest of our story.
A properly installed stage fitting is 100% efficient. There is no strength reduction. So a wire rope with a breaking strength of 100lbs using copper swage fittings and thimbles to form a sling would have a working load limit of (100 x 1.0) / 5 = 20lbs.
Wire rope clips on average have a efficiency of 80%. Same for "fist grips".
Now VERlocks and Griplocks are different than other terminations in that they don't have an efficiency rating, but a Working load limit. For instance a griplock for 1/8" wire rope has a WLL of 250 ponds. The wire rope has a WLL of 400lbs when used as a sling with an 5:1 df and 250lbs when used as running rigging with a 8:1 df.
There are other options as well such as Flemish eyes or epoxy based terminations. You will usually see these in other industries such as telecommunications.
And then there is the famous Circus knot. More art than science.
Hope this helps muddy the waters.
Ethan
Clint Eastwood
Member
With Verlocks and griplocks, de-rating the actual cable as you would with a crimp or Crosby termination is usually irrelevant because the griplocks have a MUCH lower WLL than the cable. You should consider your limit based off the weakest part of the system; usually the griplock.
Griplocks/verlocks/gripples etc are often an not a good choice for many things. Now for supporting some foam-core, spandex or other light flats that need fine adjustment of cable length, they work great. For anything approaching the WLL of an adjustable device, a fixed length cable correctly crimped and /or using a trim chain would be a better choice.
I use Griplock style devices a lot for certain scenic elements, and they are great for a lot of things when used well withing their limits.
Griplocks/verlocks/gripples etc are often an not a good choice for many things. Now for supporting some foam-core, spandex or other light flats that need fine adjustment of cable length, they work great. For anything approaching the WLL of an adjustable device, a fixed length cable correctly crimped and /or using a trim chain would be a better choice.
I use Griplock style devices a lot for certain scenic elements, and they are great for a lot of things when used well withing their limits.
