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G clamps upside down

Discussion in 'Lighting and Electrics' started by Diarmuid, Oct 20, 2006.

  1. Diarmuid

    Diarmuid Active Member

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    Hiya,

    I've just got a quick question, I went to a play tonight and about ten of the lights (Selecon Fresnel things..) and whilst they were all safety chained, they were rigged inverted, as in the light above the bar. I checked and they were just using normal G clamps.

    My understanding was that G clamps could only be used for lights hung directly under the bar, that 'trigger clamps (something like this http://versales.com/ns/theatrical/che_clamp/images/t58215.jpg) could be used for everything other than completely inverted and for a completely inverted light, you needed something more like http://www.hedcom.fi/files/hedcom/Doughty/dou_clamp_04.jpg that.

    Is that right, or are you ok with just a normal G-clamp for inverted lights?

    Thanks in advance for your help.

    Diarmuid
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

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    With a standard C clamp you can hang a light whatever way you please. They had the lights overhung at the venue you were at. Many places overhang and underhand position to pack more fixtures in. You can also "yoke out" a fixture (hang it at a 90 deg to the pipe) with a standard C clamp. C clamps are usually rated at around 500#. It is perfectly safe to hang in whatever way you need to , but always remember the safety cable.
     
  3. Van

    Van CBMod CB Mods Premium Member

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    Occupation:
    Project Manager, Stagecraft Industries, Inc.
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    I've never heard anyone, nor read anywhere that G-clamps were to only be used in the "down" posistion. As far as I have ever known whether the clamp is "C", "G", <yes there is a difference> or an "alligator" the only thing that really mattered was that it was sufficiently torqued and saftied. Sufficiently torqued means just that, I used to know some Sparkys that thought you should crank the hell of the bolt. I used to get gear back that was in really bad shape. Over torquing on any "Cast" product will lead to it's early failure. Cast iron, as opposed to, Forged, does not stretch it snaps. Tight is tight enough.
     
  4. Pie4Weebl

    Pie4Weebl Well-Known Member Fight Leukemia

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    yup I agree with the "use it how you want" for the c-clap. I do some work at a union house and all the IA guys do that, and they are nit picky on safety so I assume it is fine. (also I have never seen any cautionary notices in the s4 Manual or anything)
     
  5. soundlight

    soundlight Well-Known Member

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    We hang our fixtures every which way. Overhang, underhang, and straight-hang (perpendicular off of a vertical sidelighting pipe).
     
  6. Diarmuid

    Diarmuid Active Member

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    Wow, thanks for your help, I don't know how I got so confused I was probably just reading some advertising litreature somewhere that told me it was unsafe, in an attempt to get me to buy their clamps.

    Thanks

    Diarmuid
     
  7. ship

    ship Senior Team Emeritus Premium Member

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    A "G-Clamp," like a "J-Clamp" is bent steel which is stronger at least in bending far before breaking.

    As with the "C-Clamp" from what I haver ever known, such things can and do bend at times, and bolts do break and or also bend without breaking.

    What's better for ensuring the fixture won't fail? A clamp that has the steel clamp part of it bending around the top of the pipe, or the bolt locking it into place at the top of the pipe and depending upon that bolt not to bend or have problems? IN a roostered out fixture, it would be preferable I would think for the fixture to rotate down with gravity should it's bolt fail.
     
  8. cutlunch

    cutlunch Active Member

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    As a rule I normaly hang the lamps down from the pipe unless I really need to hang them horizontaly or with the clamp underneath. I feel there is no point in putting extra strain on the locking bolt when I don't have to.

    If the lamp is underhung this means the whole of the clamp top takes the weight across a good area whereas hanging where the clamp bend is below the bar means the bolt has to hold all that force on its much smaller area.

    I think it is in the category with the people who hang lights with the lamp bases upside down. In the short term it mighn't matter but over a few years it will slowly degrade the equipment more then the normal hanging method. Also if the lamp is not underhung you have to tighten the bolt quite a bit more just to keep the light in position. The other advantage is that unless the clamp fails catastrophicaly the lamp won't fall whereas you just need the bolt to loosen slightly and the lamp falls onto the safety chain.

    Before I get flamed I know the difference is probaly minimal but I thought I would put my ten cent's in.

    I also think if you have new students do the hanging the underhung method is easier and safer for them. More experienced people can do the overhead ones because they will be more confident.
     

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