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Seachangers and sidearms?

Discussion in 'Lighting and Electrics' started by gafftapegreenia, Nov 1, 2007.

  1. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    If I were to mount a Seachanger on a boom, would it be wise to attach a side arm so the yoke is not being torqued? We have buckets full of sidearms, but rarely use them. Today during crew one of the electricians hung two Source 4 and Seachanger units from booms sideways directly from the c-clamps on their yokes. I just wonder if, since it will be like this for a few weeks, if switching them to sidearms would be better for the instrument.

    Even thought when I ask a few others in the shop what they thought, and they said it would be fine, I have a gut feeling the sidearm would be a better idea. What does the board think?
     
  2. icewolf08

    icewolf08 CBMod CB Mods

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    Why don't you use sidearms whenever you hang lights on booms? It is a lot easier to focus.
     
  3. Logos

    Logos Well-Known Member

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    Yeah, I don't like the idea of a light hanging sideways of its clamp for a long period, and don't you have to overstress the C clamp. The hook clamps we use here certainly will also do the job but have to be overtightened IMHO. Use sidearms (we call them boom arms.)
     
  4. jonhirsh

    jonhirsh Active Member

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    Sidearms rock.

    But I would not worry about the clamp.
     
  5. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    See, this is my point, we have sidearms but rarely use them. As I'm not the only one hanging lights, and I am a Freshman, I don't have the power to mandate sidearm use. They invented sidearms for a reason right?
     
  6. soundlight

    soundlight Well-Known Member

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    Use the sidearms. Especially with the seachangers. And they're easier to focus. Funny thing, I just did booms today for our dance rig - and I know that sidearms make things easier.
     
  7. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Sidearms are probably the most under-used piece of kit in the "iron" category. One of my favorite "tricks" is to use them on truss for cable management, such as when multi needs to turn a 90° corner. No more picking cables up off the floor or tying each cable independently. Also keeps the cable from "running" where it drops off the truss to the dimmers, until you can strain relief with shackle and spanset.

    By all means, yes, use sidearms on vertical hanging positions. Those who don't are either too lazy to remove the instrument's clamp, or just don't know any better. Now if you don't have sidearms, I've found hanging a fixture (or even a mover) with yoke either US or DS makes for a speedier, easier focus. Pan becomes tilt and tilt becomes pan, but on a conventional it doesn't matter (unless it's a radial!) and all moving light consoles allow the user to "swap pan and tilt."
     
  8. ship

    ship Senior Team Emeritus Premium Member

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    I don't mind using side arms for roostering out or extending away from but not on a horizontal plane from a vertical pipe. Believe that's not what they are designed for doing or a good idea.

    Normal side arms have C-Clamps on them the same as fixtures but as opposed to fixture clamped directly to the boom, these fixtures attached to a side arm have much more torque going against and possibly over-stressing the clamp. Given the sea changer is more heavy than a normal Leko, I would be concerned for two reasons. First if your side arm is the normal ½" sch. 40 normal water pipe instead of sch. 80 water pipe, that pipe could bend. Second and more important the side arm could fail more easy in a direct proportion of side arm length to the amount of extra torque that side arm is putting on the C-Clamp - in direct relation to that.

    There is some old style side arms out there that have a bit more reinforcement to the clamp portion but if it’s the normal side arm that’s just a Altman clamp with cotter pin pipe in it, I would be concerned about the added torque over what weight is normally known for such a thing. (Again a Sch. 80 pipe is recommended.)

    A better way to side arm for these lights would be to do cheseboroughs with the desired length of batten pipe or 1.1/2" Sch. 40 pipe to the boom. The cheseborough is rated for much more weight. Another option is to use ½ cheseboroughs welded to 2" aluminum pipe, or RotaLocks which are similar to cheseboroughs but not really as good for this type of application.

    As always, safety cable each fixture not to the side arm but to the boom. A double wrapped sunday loop or Perstrusk (sp) Knot of wire rope to the boom so it cannot slide down the boom with the safety cable hooked or looped to it is possibly the best way to do this.

    I have also seen safety cables latched to eyelet rigged ½ cheseboroughs or at times C-Clamps that don’t have fixtures on them also.
     
    Last edited: Nov 1, 2007
  9. icewolf08

    icewolf08 CBMod CB Mods

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    I was taught that the forged cheesboros were not rated for this type of application. I would always choose rotalocks or the new style aluminum "cheesboros" that actually have a SWL imprinted on them. I would certainly use cheeseboros like this if I could find any paperwork that said they had a rating, but I have yet to find that document.
     
  10. soundlight

    soundlight Well-Known Member

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    We use aluminum cross-pipe connections that have allen keys, put 1.5' sections of 1.5" sch. 40 pipe on them, and hang instruments on the top and bottom of them.
     
  11. Jezza

    Jezza Active Member

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    Ship--those were some great ideas about safetying off to a boom. Never found a good solution, but I like the double wrapped sunday idea. I think using some 6mm static rescue line for that on my booms would be perfect.

    Soundlight--the only thing that bothers me about the Allan key clamps is while they essentially are a friction clamp and the set screw is only supposed to provide tension on the jig, they inherently seem less stable to me than a cheesborough, especially in a torqued, constant stress situation. I agree though, my preferred method has always been 1 1/2" schedule 40 as opposed to side arms.

    Another great use of side arms-- A good way to keep cables off the same pipe as instruments to facilitate hanging is to clamp 12" sidearms every place you have a pick point vertically with the arm facing up towards the grid. Then attach a piece of standard drapery "bottom pipe" to the tops of the sidearms, sundaying off this new pipe to the ropes to keep it from falling over. Tie off your soco to this new pipe and drop your tails down.
     
  12. soundlight

    soundlight Well-Known Member

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    We use sidearms on the ends of our electrics in order to keep the huge mult cables from getting out of order - a pair of sidearms in an upward "V" pattern keeps the mults in check.
     
  13. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Hanging on a vertical pipe or boom is exactly why City Theatrical designed the "Safer Side Arm"
    [​IMG]
    Also as long as we are sort of on the topic are you all aware of "The Light Source's" Mega-Drop Down? 6", 12", 18", 24", and 36" extensions that screw in between the C-clamp and the yoke. Pretty cool... I'm getting several for the black box.
     
  14. ship

    ship Senior Team Emeritus Premium Member

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    Not sure if rescue line fulfills the concept of a safety cable. Fairly certain it would not due to the fire factor. Big spark of light hitting boom, rope catching it even if flame resistant and melting type thing in no longer being a safety cable. That's in broad concept even why many venues are requiring GACFlex for the spansets as opposed to normal spansets also in many cases. Wire rope core spansets... good stuff, as with steel in the air. For me at least a “Sunday” is a loop of wire rope that’s crimped into a circle. Doesn’t quite grab a vertical pipe as well when not under tension - given the double loop on the pipe even, but once under tension it will either grab or stop when it hits something else. Not gonna melt, and not gonna fall to the floor. Only problem being the loop at the point of stress - where the safety cable hooks to it - minimum bending radius of wire rope on safety cables if not especially a sunday in use will play a large role in it's safe use very much dependant upon weight and how far the fall is. (See below on supplemental clamps or stop bolts and safetying off to the ceiling. By the way if boom on stage that doesn't have top clamp - it should be safetyed to the grid in some way so it cannot fall over - perhaps a spot line and ladder might be necessary as concept if necessary. This getting into other topics of safety.) Could also wire rope off to a rig point on the ceiling above the boom as a concept. This especially if using a standard side arm I might recommend to do. Over the sunday, much less chance for slippage short of something to stop that slippage which becomes extra materials. Perhaps something as simple as wire rope off to eye bolt mounted I-Beam clamp mounted to the same steel the boom is attached to as a simple method that could in some instances be work able given short side arms. (and now a whole new debate...) gafftaper, brilliant and perfect in solutions all materials and brands presented.

    Could also in all concepts of safety cable and the friction clamp thru-bolt stops to the vertical pipe or use secondary clamps of almost any type for use as a stop also. Normally I would in the past just put an un-used C-Clamp below what ever I was doing. This given later other options. I’m sure sources like Altman, J.R. Clancy, Sapsis Rigging, and City Theatrical have specialized products for doing a boom side arm also, if not Tomcat.

    Not familiar with a allen key clamp if the allen key is what’s providing the friction as opposed to a socket head flat head screw that mounts the cheseborough to what it’s mounting. Such half cheseboroughs when mounted to the yoke of a fixture are correct in being termed friction clamp, but ya gotta remember that it’s on a vertical pole not roostering out on a horizontal batten. You not just have that friction, but also have the torque keeping the clamp in place - this given the friction clamp is at a proper tension in the first place. Also see the above options for safety by way of bolts, secondary clamps etc. to prevent sliding.

    Another point that might be discussed given problems with cheseboroughs is a scaffold clamp type cheseborough that’s forged steel and hex bolt base plus designed for a 1.1/2" pipe in similar situations, verses say an aluminum cheseborough that’s wing bolt based and engineered for quick install truss install but often not as wise to use for water pipe in a vertical situation such as on a boom. I would trust the specs on what makes a scaffold clamp to sufficiently do the job and believe that’s what I have always been taught is the proper way to do this even back before the days of Seachanger. I’m also changing my opinion of the Seachanger fixture attached directly to a batten by way of normal C-Clamp - don’t think even that’s sufficient even with a heavy duty Altman clamp or heavy duty ETC clamp. Need a half cheseborough in my opinion and see above about slippage safety. Otherwise another similar type of clamp only possibly. It’s a heavy fixture on a vertical pipe. We are not just talking slippage from a mounted elevation above dead hang, we are also talking side loading torque on that clamp. Normal C-Clamps with a bolt to hold the fixture won’t have that concept of what is it 10:1 safety factor - the bolt is gonna give if the clamp is not over-torqued in failing or bending at least. This is a concept beyond just the normal of hanging a 6x12 on a stock side arm on a boom that I also don’t recommend. Such a concept is normal to the industry and changing,... heck I can remember using such C-Clamp mounted fixtures and side arms as ladder rungs as I climbed the pipe, but don't include that above safety factor - something hitting it or falling against it in a side loading situation is I believe the general point to the latter posts on this topic. C-Clamps in general and especially side arm C-Clamps are just not designed for mounting on a vertical pipe. Sure, you can say mount a 6" Fresnel with out a problem, after that it's a bit more getting into stuff that should not be done with the correct safety factor or design factor for what you are doing.

    Also point of definition - a side arm for me in a typical way is an Altman normal C-Clamp with a (typically) ½" Sch. 40 water pipe and Tee mounted on it. Both ends of the pipe are bolted or in some way such as cotter pin prevented from coming loose by way of the clamp or tee. Problem is as with a normal C-Clamp, half the force in holding it in place is that bolt and holding that bolt plus the rest of the clamp is all dependant upon the cast metal. Anyone ever get the non-domestic C-Clamps mixed up into their stock years back before? Got a sort of varnish covered black paint on them Total crap metal in the casting and fail easily in all ways. A more heavy ETC style clamp won’t accept a Sch. 40 pipe and to my knowledge short of reaming the hole is not in general service as a side arm. Such clamps might stand up a bit better in the casting but reaming them out for a pipe would destroy the engineering concept behind them. The heavy Altman clamps also are not really designed for such side loading in any better way.

    Other options I have seen is aluminum ½ cheseborougs welded to a section of aluminum structural tubing. Not sure if I have ever seen a steel version of this. This concept of cheseborough that’s portable and pipe attached to clamp would work but as pointed out is a friction clamp and one not really sized for the smaller that 2" OD tubing 1.1/2" ID steel water pipe used on a boom. Works often but not really sized for a vertical boom situation to work best.

    My recommendation and what I remember others in the past recommend stands - the scaff cheseborough with a pipe in it is the best side arm for a vertical boom. This especially given the vertical pipe.

     
    Last edited: Nov 2, 2007
  15. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Um, Gaff, wouldn't 1/2" threaded rod do the same thing at way less cost? Screw the top into the C-clamp and put a nut on the top & bottom of the yoke. Cut the rod any length you want (not to exceed one meter). I like the fact that the Mega people recommend red Loc-Tite, but I would suggest a Nylok as the lowest nut, and a jam nut at the C-clamp. It any case, be sure to keep everything plumb so as not to exert excess force on the C-clamp.

    Ship, I understand your safety concerns, but sidearms are intended to be used horizontally on a vertical pipe. I've often used 24" Dbl-Tee to hang two 15 lb. fixtures, but it's best to keep them as close to the vertical pipe as possible. For the safety I usually use the clamp I removed from the fixture as a stop, and an extra safety clove-hitched around the vertical pipe. Even if there is a failure, at least the safety will keep the fixture close to the vert. pipe all the way down, and unless one is standing on the 50 lb. base, one wouldn't be injured; scared perhaps, but not injured. I rearely even used safety cables in coming to Las Vegas in 1991. Is their use "mandated" somewhere or just a good practice? But then I grew up with ungrounded pin connectors too. I do like the "safer sidearm" series, but feel they're grossly over-priced, and would build my own if I were hanging anything heavier than a standard ERS. How much does a seachanger weigh? That is, if it could weigh eggs?

    By the way, the Hex Key clamps are known by their primary manufacturer, Kee Klamps, or Speed Rail, and are NOT to be used for suspended loads. I've always used forged steel Cheeseboroughs for iron pipe and aluminum Cheeseboroughs for aluminum tubes, or at least tried to. I like Rota-Locks too, but they don't work so good at other than 90°. And people confuse them with Roto-Locks.
     
  16. Logos

    Logos Well-Known Member

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    This is what I usually do. Just as a matter of interest why limit your length to 1 metre? I don't remember ever going longer than one meter but do you have a specific reason. I'm sure breaking strain isn't an issue are you worried about the rod flexing under strain?
    Of course I wouldn't put any more weight on this than a single PAR can or 500W Profile/fresnel. No movers or stuff like that.
     
  17. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    The "one meter limit" was primarily to annoy Gafftaper, but my feeling is if you have to taildown a light more than that, something is in the wrong place to begin with. For longer than 3' and for movers, we use upside down "T" pipes from the truss. Sometimes, if the ME or gaffer has thought ahead, we use the piece of hardware known in the film industry as a "trombone."
     
    Last edited: Dec 12, 2007
  18. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Yes 1/2" pipe would work, but I doubt it would be as strong as their solid aluminum rods are. They also are pretty reasonably priced at around $10 for the 12" version. Finally they are designed for this purpose so if it fails they are the ones who get sued not you for your MacGyver project
     
  19. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Since no one answered, I had to look it up myself. A 419, with clamp and Seachanger module, weighs 28.3 lbs, or 12.8 Kg. Still less than two standard S4s on a 24" Dbl-Tee sidearm.

    Gafftaper, I said 1/2" threaded rod, not pipe, and I can buy steel 1/2"-13 x12" threaded rod for about $3, plus nuts & washers. Your solution is more expensive, but less likely to be purloined for other purposes, I'll concede on that. Did you order long, or additional, safety cables, to go with your taildowns?
     
  20. jonhirsh

    jonhirsh Active Member

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    But Threaded rod sucks to work with. Especially when the designer decides to hang the entire plot with it. Then changes the length of the rod after you have hung the whole show. Home depot loved me by the third rehang.


    JH
     

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