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Rigging with the cheap stuff...

Discussion in 'Scenery, Props, and Rigging' started by ricc0luke, Mar 21, 2005.

  1. ricc0luke

    ricc0luke Active Member

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    Unfortunatly, I do not have the luxery of using the good- factory backed aircraft cable and the good crosby clips- (not that I know the ones at the hardware store are bad because I honestly can't remmber if they are forged or not). I am going to be stuck with what ever the hardware store has- and I know they don't have the great aircraft cable- so what I am asking is if I am flying a light weight foam faced flat what size would you recomend when using the cheap stuff, and, what size would you recomend when flying a 4x 10 foot door flat?

    Please save the lectures on using the good stuff for another time. I don't have a choice- it is this or piano wire...

    Thanks.
     
  2. Sam_

    Sam_ Member

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    If it's not safe, don't rig it. Find some other way.
     
  3. ship

    ship Senior Team Emeritus Premium Member

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    Soap box in doing it legit but being kind. It is correct that if you can't use the proper methods and materials you should not do it or find a different way. Given you are going to have to anyway here is some info on how safely.

    First all rigging components from your safety cables to your head blocks should be tracable as to who manufactured the part and what it's safe working load limit is. It should also be inspected for safe condition before use. You should keep this info on file for liability reasons if it is not stamped on the product.

    Given standard hardware store equipment, a little extra leg work should be all that's necessary to use it.

    Chances are what equipment they carry is either from National (a sub company of cooper I think but could verify) or Cooper both of which will have catalogs or websites you can get this info from.

    www.coopertools.com

    Load ratings and appropriate uses of the equipment need to be followed. If say their wire rope or wire rope clips from the website catalog say for instance "not for overhead lifting" it should not be used. If you still have to use it, make sure those in charged of you using it see that note about the gear being used so it's their liability for approving of it's safe use and not yours.

    So in getting the wire rope, note also from the spool the info of who made it or get the info on where the store got it from. Get the lot number etc. also from the spool.

    You now have both manufacturer and tracable elements of it such as lot number.

    Most hardware stores will stock a 1/8" 7x19 GAC or Galvanized Aircraft Cable. This is the same stuff for all intensive purposes as you would get from a rigging supplier - and most of it these days will all come from China no matter who the supplier is. All of it is rated for a 280# Safe Working Load.


    The wire rope clips available will probably be of the Mailiable type and not drop forged. Again find out who made or supplied them to your store, and get a lot number. The safe working load or deduction for that on the cable for a mailable wire rope clip is 60% instead of 80% for that of a domestic Drop Forged one.

    Given these type of wire rope clips, your new safe working load will be 168# per lineset which is OK. Follow the directions from the website as to proper torque, installation and required number of them. I might even add a third wire rope clip in the termination for safety.

    You can also step this up to 3/16" wire rope and clips for more of a SWL by way of the wire rope clips.

    Otherwise if a very temporary install and you have a real rigger do so, a circus knot is 80# effective. Short of proper instruction, don't try it however. Much less the rigger might have a stash of proper wire rope clips.

    A further option would be to pre-purchase a spool rope such as a spectrum braid from Sapsis Rigging amongst many suppliers. Than again in pre-planning, even McMaster Carr sells drop forged wire rope clips and wire rope that is rated. This amongst mail order companies such as Sapsis, Rose Brand, Stage Technologies/Secoa, Peak, John Sakash, Atlanta Rigging, Reed Rigging, J.R. Clancy, Fehr Brothers, Fisher Theatrical, Texas Scenic, Design Lab, Grand Stage, Mainstage Theatrical, LVH, Rockford, Stage Rigging, Tiffin Scenic, Total Tool, Ver Sales, I Weiss, and Merrill



    As for hanging the door flat from it, and assuming the proper hanging hardware is used, there is some safety factors already involved in doing so. Standard rigging 4' on center should be sufficient to fly the door flat given a soft flat construction no more than 12'. You might need some folding stage jacks on the flat to help support the flat/doorway.

    You did not mention thimbles either. Given hanging hardware, you will need a thimble at least in attaching to the ring.

    This is opinion of course but given I am not there your TD or having a real rigger on site is necessary to verify these assumptions and the actual equipment to be flown will be safe.
     
    TEarlywine and (deleted member) like this.
  4. ship

    ship Senior Team Emeritus Premium Member

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    Let me be very clear in the above message before the flame war starts.

    First, even hiring a rigger for a day to ensure it’s done properly and to teach sounds like a good idea. At that point they can ensure things required like thru-bolting the hanging hardware, proper installation and use etc. of the materials.

    Second, I do not understand why given prior planning you would not have time or ability to purchase the materials before hand from a respected source and instead would in the future have to purchase them at a hardware store. At very least if in an urban area, Fastenal or Grainger might have a branch that you could shop at which would have the proper supplies. Much less a electrical supply store might stock proper drop forged wire rope clips - but just about any theater supply store certainly would. Another local theater might also have some in stock to buy or borrow.

    My main concern is not about the wire rope. As I said, it’s most likely going to be the same stuff anyone else would be able to supply and as long as you have the lot number and manufacturer or supplier noted it should be fine. It should say something like 1/8" or .1250" 7x19GAC on the spool as opposed to being of another type such as plain steel which will have a different load rating. I doubt they will have anything other than galvanized wire rope however.

    The wire rope clips thus are the primary concern given what you posted. While in my own high school that’s what we used, and such things are in general safe, these days with further study it might be found a valid reason not to use malleable wire rope clips would be in their shock load rating or lack there of. Given a 60% rating it’s probably already compensating for material strength and quality, that’s static loading. Should the flat bump something, it could become factor that would stand in the way of using these clips. The Crosby Group Website as well as Sapsis Rigging’s “Heads” articles should have lots to support this.

    My recommendation is to buy some Will, Chicago or Crosby brand drop forged wire rope clips, or at very least get some import ones from a trusted supplier. I’m not a fan of other than domestic rigging parts - quality control and tolerances especially with the threads are not as good. Once bought some turnbuckles from Sapsis Rigging. They were imported and I rejected them in that the tolerances of bolt to nut were really bad. Never gone back to other than domestic rigging parts other than for wire rope where I have no choice. Unfortunately as a result from the past tariff on steel we once had, the US reversed this policy and put a tax on domestic steel which makes rigging stuff here much more expensive. Still worth the price.

    My recommendation is to pre-buy wire rope clips - the quality ones and you will not have a problem with doing something that you know is questionable. It’s probably safe, but highly not recommended.
     
  5. chieftfac

    chieftfac Active Member

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    At least he's thinking....

    I will print out this thread as more expert opinions are added and use it for ammo the next time our resident theater group tries to tell me it's safe to fly a 75 lb load with fishing line...because the director doesn't want to see the cables...(thus I rig everything in our house...no schooling just lots of books and the gift of having a pro live not four miles from the facility)...I've done several community theater tech around the area and I can say that only 2 of the 14 I've worked were even close to hitting the mark on actor safety...and one I walked out on because I didn't want to be a part of it....they did have someting fall and luckly no-one got hurt...

    sorry for flaming...

    I just hate to see people not think of the safety of everyone involved...sometimes the show shouldn't go on....no matter what
     
  6. ship

    ship Senior Team Emeritus Premium Member

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    1/16" Black Oxide Coated Galvanized Aircraft Cable has a Safe Working load (normally 10:1 for the theater) at 95#. I would challenge your guests and directors to notice it where more normal 1/8" black wire rope would show up.

    The fish line in being rated for 75 or more pounds is a statement of it's breaking strength not it's safe working load. Don't need much of a SWL where fish are concerned. Industrial rigging components are normally at a 5:1 safety factor so for stage purposes you should half that statement.

    I stock fish line for use in shows along with all kids of wire rope and wire rope clips. Don't even think there is a such thing as a drop forged 1/16" wire rope clip - but there is oval Nicopress Sleeves in that size, along with in the case of our 1/16" wire rope core chain hoist feeder cable a good crimp tool in crimping a steel high temperature ring terminal to it, if not at times supplemented by solder is used by us on equipment such as 2-ton chain hoists to help ensure that the cable feeding the hoist will not if snagged become a safety hazzard as it rips out of the hoist otherwise. I would not recommend ring terminals for rigging but for a more mechanical application they work well in terminating it.

    Here is the ammo:
    Given this deduction in the safe working load for a 1/16" wire rope clip at 60% thus 57#, one more simple of mind will than say that the fishing line thus stronger. You than say that's not so and ask what type of knot you were supposted to terminate the fish line with?

    Per page 192 of Glerum's Stage Rigging Handbook 2nd ed.

    A bowline is 60%
    Figure Eight 64%
    Two Half Hiches 60 to 65%
    Square Knot 43%
    Clove Hitch 75%
    Clove Hitch w. two Half Hiches 65%
    Eye Splice w. Thimble 95%

    Let's say a Bowline given you can tie it in fish line and it won't slip. Your pre 10:1 safety factor, given those using it would not understand safety factors, after knot working load would than still be 45# or right above that of #4 Tie Line at 40# in this case for it's own SWL. Given the standard for the industry 10:1 safe working load, your fishing line with a bow line knot than is rated for 4.1/2 pounds and that's about all the industry in maximum loading will use such fish line for.
     
    TEarlywine and (deleted member) like this.
  7. Radman

    Radman Well-Known Member

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    So if you must use fishing line... use a LOT. ;)

    ex.
    _____________ <--batten
    _|_|_|_|_|_|_|_ <--fishing line
    |____________|<--1/2in foam 1'x8' at about 5#


    Overkill is key! ;)
     
  8. chieftfac

    chieftfac Active Member

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    A big thank you...

    Thanks Ship...I looked up the page referance you noted....that with this thread will help me a lot....Our theater group is a seperate 501(3)c...so sometimes they think I'm just making this stuff up..(to be a prick or control them, I don't know which)..before I started here some 13 years ago they had full run of the place and did all teching with volunteers...and of course there is their favorite response "...we've always done it that way before, and nothing ever fell..." to which I reply "you were damn lucky"

    I took over all tech things on stage ( I was hired as building maint.) when they stripped a batten of 5 (yes 5) 12 x 4 flats, with no ropes on the batten side or removing any weight from the arbor...on the way out the batten caught on a industrial gas heater (should never have been there anyway) and ripped it off the wall...thank god no explosion, and I knew where to shut the gas off quickly...I didn't know you could bend 1 1/2 schd. 40 pipe at a 45 deg. angle...I've got the pic somewhere, I should post it...

    Thanks again ship...you're a wealth of knowledge...
     
  9. ship

    ship Senior Team Emeritus Premium Member

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    I get that statement a lot also. In my case it's more arguing that something that's always been done that way is against code, and that there is better methods for doing it. It's hard to change things over night but in little steps over time you can often look back on huge improvements, much less as time goes by the larger ones are easier to make happen.

    Have my own long term projects that every once in a while I make progress with.
     
  10. propmonkey

    propmonkey Well-Known Member

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    why not just order from www.fehr.com thats where we order our thimbles, cables and nico selves. decent prices.
     

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