Rigging with cable stops question?

Fusrohdave

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Joined
Jun 11, 2019
Location
New Jersey
Hey All,
Im the TD at a local theatre here in NJ and we are currently doing a production of Mary Poppins. I have to fly a long broadway style flat,
3-4” thick and about 3’x25’ in total. I came across some cable stops, the small round sleeves meant to be crimped onto the end of aircraft cable, and I realized I’ve never seen them used in theatrical rigging applications, at least as far as hanging on the batten is concerned.

I was wondering if there is a reason for this, and if they’re an effective way to fly light scenery? Normally for this application I would use hanging iron or a D-ring, but I thought this might be a good idea considering the whole unit is about 100lbs total.

Anyone know if the cable stops are rated for the full strength of the cable? My guess is no, probably around 25-50%. Any info at all is helpful!
 

RonHebbard

Well-Known Member
Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
Hey All,
I'm the TD at a local theatre here in NJ and we are currently doing a production of Mary Poppins. I have to fly a long broadway style flat,
3-4” thick and about 3’x25’ in total. I came across some cable stops, the small round sleeves meant to be crimped onto the end of aircraft cable, and I realized I’ve never seen them used in theatrical rigging applications, at least as far as hanging on the batten is concerned.

I was wondering if there is a reason for this, and if they’re an effective way to fly light scenery? Normally for this application I would use hanging iron or a D-ring, but I thought this might be a good idea considering the whole unit is about 100lbs total.

Anyone know if the cable stops are rated for the full strength of the cable? My guess is no, probably around 25-50%. Any info at all is helpful!
@Fusrohdave Please elaborate, how are you planning to attach / terminate your cables to your flat?
The following are NOT suggestions, merely my inquisitive queries:
- Drilling a hole through your flat horizontally in an US / DS direction, bending your cable 90 degrees, threading it through the hole and crimping your end sleeve on the free end?
- Routing your cable vertically down through a series of holes through cross-members within your flat all the way to the bottom where you'd counter-bore to permit the end of your cable to reside within the flat's bottom surface and land flat on your stage?

Prithee do tell; what are your plans for attachment and termination of the free / lower ends of your cables?

Also, how many cables are you planning to use across the 3' width of your 25' tall flat??
While you're mentioning your flat is approximately 100 pounds, this may be true but it will get much heavier in a hurry if / when it swings slightly and comes up under a nearby 1400 pound LX pipe, pauses ABRUPTLY for a moment before your attachment point proves to be the weakest link in the chain and your flat's either hanging from one remaining cable or, worse yet, proving gravity is still functioning by crashing to the deck.
Calling @What Rigger? and @egilson1 Comments please.
Toodleoo!
Ron Hebbard
 
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Fusrohdave

Member
Joined
Jun 11, 2019
Location
New Jersey
https://www.nicopress.com/products/w6-871-18-j Looks like they are good for 'approximately ' 50% of the breaking strength of the wire rope.

What would the end stop rest against? How would you adjust for level?
The cable is all cut to the same length and the flat has to sit on the ground so the idea is that I would drill a 3/8” hole about 1/2” deep for the stop to rest against, and pass the wire through and crimp the stop. my theatre has an old rope and sandbag fly system so I can adjust for level by adjusting the batten. Not exactly the best way but it works.
 

Fusrohdave

Member
Joined
Jun 11, 2019
Location
New Jersey
@Fusrohdave Please elaborate, how are you planning to attach / terminate your cables to your flat?
The following are NOT suggestions, merely my inquisitive queries:
- Drilling a hole through your flat horizontally in an US / DS direction, bending your cable 90 degrees, threading it through the hole and crimping your end sleeve on the free end?
- Routing your cable vertically down through a series of holes through cross-members within your flat all the way to the bottom where you'd counter-bore to permit the end of your cable to reside within the flat's bottom surface and land flat on your stage?

Prithee do tell; what are your plans for attachment and termination of the free / lower ends of your cables?

Also, how many cables are you planning to use across the 3' width of your 25' tall flat??
While you're mentioning your flat is approximately 100 pounds, this may be true but it will get much heavier in a hurry if / when it swings slightly and comes up under a nearby 1400 pound LX pipe, pauses ABRUPTLY for a moment before your attachment point proves to be the weakest link in the chain and your flat's either hanging from one remaining cable or, worse yet, proving gravity is still functioning by crashing to the deck.
Calling @What Rigger? and @egilson1 Comments please.
Toodleoo!
Ron Hebbard
I have 10 points where I will be hanging across the unit and I should specify it is 3’ tall and 25’ wide. It’s basically the wall of a house up to the chair rail.
Im aware the load increases as I fly which is why I wanted to make sure the cable stop was rated to the same load as the cable like an hourglass sleeve is. It doesn’t look like it though so I’ll stick to standard hanging irons and turnbuckles.
 

BillConnerFASTC

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Joined
Jan 30, 2010
Location
Clayton NY 13624
You could make a case for 1/8" with a breaking strength of 1760 pounds. Stop derates that to 880 pounds. 1:8 design factor to 110 pounds. Your whole 100 pound unit could be safely - load wise - be hung on one line.

A more careful analysis would be needed for 1/16" gac - breaking strength 480 so derate to 240 and 1:8 is 30 pounds per line. One end hangs up and at least half the load is on one line Without knowing more, I can't tell you if it's OK or not. 3/32 could also work, with a 57 1/2 pound load max per line, but requires more review based on details.
 
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bobgaggle

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Joined
Nov 19, 2007
Location
Philadelphia, PA
A couple of things:

your "Broadway" flat is 3-4" thick? ok.

My thoughts. If this is in fact a wood framed Hollywood flat, best practice dictates that you rig from the bottom to keep all wood joints in compression.

Standard framing these days is 3/4" thick. You want to counter bore the bottom rail of your flat 1/2" for the stop to hide in? so you've got 1/4" of wood holding the weight of your flat? No good.

Adjusting for level by re-trimming your pipe is the most headache prone method. You want 10 lines to hold your 100lb. flat (overkill), but I'm guessing you've only got 4 or 5 on your hemp system. You know when you yank on one of the lifting lines, the pipe starts to smile, you have to adjust every single line to get the pipe straight. Basically I'm saying you've got 14-15 separate variables to adjust just right, and that's a hassle. Not to mention re trimming at strike.

Far better to leave the pipe where it is, bolt a d-ring and keeper plate to the bottom rail of your flat and put a turnbuckle between the d ring and your thimbled eye. Depending on how you've built this thing, I can't see why you'd need more than 4 lines to rig it.
 

RonHebbard

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Premium Member
Joined
Jun 12, 2004
Location
Waterdown, ON, CA
A couple of things:

your "Broadway" flat is 3-4" thick? ok.

My thoughts. If this is in fact a wood framed Hollywood flat, best practice dictates that you rig from the bottom to keep all wood joints in compression.

Standard framing these days is 3/4" thick. You want to counter bore the bottom rail of your flat 1/2" for the stop to hide in? so you've got 1/4" of wood holding the weight of your flat? No good.

Adjusting for level by re-trimming your pipe is the most headache prone method. You want 10 lines to hold your 100lb. flat (overkill), but I'm guessing you've only got 4 or 5 on your hemp system. You know when you yank on one of the lifting lines, the pipe starts to smile, you have to adjust every single line to get the pipe straight. Basically I'm saying you've got 14-15 separate variables to adjust just right, and that's a hassle. Not to mention re trimming at strike.

Far better to leave the pipe where it is, bolt a d-ring and keeper plate to the bottom rail of your flat and put a turnbuckle between the d ring and your thimbled eye. Depending on how you've built this thing, I can't see why you'd need more than 4 lines to rig it.
@Fusrohdave Since you've told us your flat is ~3' tall by ~25' wide AND it's the wall of a house from the chair rail down to the floor, rather than counter boring into the bottom, why not add baseboard molding and attach your baseboard a little lower on your wall so the lower edge of your baseboard lands on your stage deck while the bottom of your flat remains 3/4" or 1" above your stage; this would gain you clearance to properly affix hanging irons using bolts / machine screws into nuts with washers or T-nuts.
Toodleoo!
Ron Hebbard
 

danTt

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Joined
Aug 24, 2011
Location
NY
There are
I have 10 points where I will be hanging across the unit and I should specify it is 3’ tall and 25’ wide. It’s basically the wall of a house up to the chair rail.
Im aware the load increases as I fly which is why I wanted to make sure the cable stop was rated to the same load as the cable like an hourglass sleeve is. It doesn’t look like it though so I’ll stick to standard hanging irons and turnbuckles.
10 attachment points? Why so many? If your unit weighs 100lbs total, you're looking at like ~10-15lbs max per attachment point in a normally loaded situation if you had ten points. I'd think 4-5 would be plenty.
 
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egilson1

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danTt

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Location
NY
We've been using stops for wire rope ladders for many years. As long as you de-rate the wire rope properly you're ok. The issue becomes will the hole in the wood resist the wear and tear of the wire rope and copper fitting?



@BillConnerFASTC , the DF for non-running rigging is 1:5, not 1:8. Also most 1/8th GAC has a breaking strength of 2000lbs.
I'd probably use an appropriately sized washer between the stop sleeve and the wooden toggle.

Also, isn't it better to say "A commonly recommended DF for non running rigging is 1:5"? There's no such thing as "the" design factor.
 

BillConnerFASTC

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Jan 30, 2010
Location
Clayton NY 13624
the DF for non-running rigging is 1:5, not 1:8. Also most 1/8th GAC has a breaking strength of 2000lbs
I use the 8:1 design factor when it's used in overhead lifting as this is. It's still subject to impact loads. For me it has never been the flexing over a sheave - I think what you mean by "running" - but impact (shock) loads.

You're right. I googled for breaking strength because I don't use 1/8" much, and found 1760. I just googled again and found 1700. So I guess before assuming any breaking strength based on size, you better know the source and what that cable manufacturer states.
 

What Rigger?

I'm so fly....I Neverland.
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Aug 24, 2006
Location
PPT.
Never have used a stop as a hanging point, especially in this sort of situation. Going back to the stop being the last in a series of safeties for a wrapped drum- yes. But again, with 4 (or more) wraps on a drum that is at least 4 times the diameter of the wire rope, the wraps aren't going to move but in an extreme and highly unlikely scenario (this set up is called a "tensionless hitch" and it's a beautiful thing).

If you don't have the correct tool and the matching manufacturer no-go gauge, stay away from this as well. Nico tools (National Telephone) require Nico gauges, otherwise if you have a failure, Nicopress won't warrantee the sleeve, or anything.

I'd encourage finding some other way of doing this, along the lines of traditional hanging hardware, but without further info I'll stick to the CB standard of not getting too detailed about how to accomplish this.
 

thecoin

Member
Joined
Dec 10, 2015
Location
St. Cloud MN
I've got nothing to add to the safety of said choice.

But i'd stick to eye bolts and the like for ease of hanging. If your cables are not all crimmped perfectly then you'll have a bad time. If the battens are old and wiggly... ect.
Turnbuckles are my best friend and if i can't add them to the unit at the unit (not at the batten) it makes for a big hassel when things are a little off.
I've forgone crosbies for this reason.
Nico/shakle/turnbuckles/thimbles - buy them for (their) life
rigging warehoue - best price i've found

Thank you
 
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Lots of good advice here, especially in terms of the wire rope and terminations. For what it's worth, I have rigged very light scenery with cable stops like you describe before but they wouldn't be my first choice and when I have, I've upped my design factor to something like 10:1 to be safe(r).

I only chime in as I haven't seen anyone else here mention the construction of the flat itself. Can you verify (to yourself, if no one else) that it's built to fly? What fasteners were used? I wouldn't trust just staples. Are all the joints glued? Are they all butt joints (traditionally, the worst kind of joint to accept glue...)? If you're drilling down through toggles (you mentioned Broadway flat but it's 4" thick? Are you SURE you don't mean Hollywood where the framing is perpendicular to the face of the flat?), those toggles should be reinforced somehow with some kind of scabs (i.e., 1/4" ply keystones/cornerblocks, etc.), or even steel corner brackets bolted to the framing.

Flying flats are strongest when their vertical framing members (i.e., stiles) are the ones carrying the load. Any internal framing, like toggles, are just there to help keep shape and/or support of the facing material. KEEP THAT IN MIND WHEN YOU RIG IT TO FLY OVER PEOPLE'S HEADS.

I'd echo others here that 10 lines seems needlessly extravagant. The more lines you have, then harder it will be to level the piece out AND to ensure that each line is taut and taking its share of the load. I don't remember if there's a maximum span between lines but I've generally put lines every 4-6 ft in wood. When I frame in steel I might go as far as 10ft but it all depends on the framing and how the piece is built (and the diameter of the cable...).

Good luck!
 

Ted jones

Active Member
Joined
May 6, 2014
Location
Chicago
Me personally, I would not use them in this case. They are stop sleeves. There are many places they can fail depending on how you handle them. Wrong tool, wrong sized hardware to stop against, shock load, lack of adjust-ability, I can go on, and on.

The norm in this rigging is to use thimble eyes with copper oval sleeves, sometimes called Nico-Sleeves, sometimes call duplex sleeves. There is more bearing area between the two parts of the cable so you have more area to not be perfect in your crimping. Not to mention the stronger connection.