Are C-clamps rated?

Not unless it's meant to be used for a true cyclorama, aka "wrap cyc." Take a picture, didn't <removed> notice this? If it's minor, it's probably okay, but if it's major
It COULD pose a serious Safety Hazard!
ALL rigging in ALL venues should have a Safety Inspection,
by a Qualified Individual/Company,
minimally annually.


I thought most battens used in theatre are black, but for some reason this looks like aluminum, no that doesn't make sense, I guess it is steel, whatever it is, it's very shiny.

I'd qualify it as a "pretty noticeable bend", however, it's on the pin-rail system, so 1. I won't be flying it in anytime soon to take pictures. 2. The pin-rail gets used like once every four years.

I don't know what the fuss is <removed> installed it.
 
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I thought most battens used in theatre are black, but for some reason this looks like aluminum, no that doesn't make sense, I guess it is steel, whatever it is, it's very shiny.

I'd qualify it as a "pretty noticeable bend", however, it's on the pin-rail system, so 1. I won't be flying it in anytime soon to take pictures. 2. The pin-rail gets used like once every four years.
Sounds like it's an aluminum-alloy, just like what lighting trusses are made of. See if its O.D. is 50mm OR 1.90". If 50mm (aluminum), probably installed on the pin-rail system to save weight (fewer/lighter sandbags). The only flaw in that logic, particularly for an HS, is when someone, who doesn't know what they are doing, overloads a point on the batten and bends it. IT SHOULD BE REPLACED BEFORE BEING USED AGAIN. Bring this to the attention of your Drama Director/Facilities people. Stage Battens should generally be 1.5" BIP, Schedule 80.

And if aluminum, one should not use C-Clamps on it without "Truss Condoms" (Truss Protectors). Wow, almost brought this back on topic...
 
I hate hanging lights on unistrut, i dont know what unistrut is truely rated for, i have never heard numbers but there is a limit to everything.

Well there has got to be numbers for it somewhere. It is used extensively in nuclear power plants for hanging everything from wire-ways to core cooling systems. The stuff that goes into these plants goes through some amazing testing and ratings. My only gripe is that it is pretty heavy.
 
This is a really frightening topic I had never thought about. It's a great reason to preach good safety cable use and to only allow 6" crescent wrenches. I can't believe with all the safety stuff we talk about that one of the most critical pieces of hardware on every stage isn't rated. That's amazing!

We don't have any 6" wrenches, the guy in charge of tech says you can't get stuff tight enough with them, only 8" here...
 
Ok, we've been over this dozens of time, but if you need an 8" wrench to get it "tight enough", you are either A) too weak for a 6" wrench B) over-tightening the clamp.
 
Man you can never get anything too tight. i just use my 24v dewalt impact on every bolt i come across just to make sure its tight. 250ftlbs of torqe insures that its good and tight :D


DISCLAMER!!!!!!!!!!!!
I'm completely kidding
 
Simple answer, paint the 6 inch wrenches blue, and the 8 inch wrenches pink with flowers. Should fix the problem ;)
 
We don't have any 6" wrenches, the guy in charge of tech says you can't get stuff tight enough with them, only 8" here...

I'll say it again... finger tight and then give it a half turn with the wrench. It really doesn't need to be any tighter than that... if you've got decent strength in your hands you can do that with a "Mega Combo Wrench"... they are what 3 1/2" long?

Do all your battens have deep gouges in them?
 
Man you can never get anything too tight. i just use my 24v dewalt impact on every bolt i come across just to make sure its tight. 250ftlbs of torqe insures that its good and tight :D
DISCLAMER!!!!!!!!!!!!
I'm completely kidding

Nice one! Tim you are my new hero.
 
Well, I wanna add $.02 too!! Personally I like the 8". I am a fairly large person and the 8" feels better in my hand. A 6" just feels small, like a toy. But as far as what other people use, it shouldn't matter. IMO, anything larger than a 8" is just just overkill. It's big and cumbersome and will just get in the way more. If someone showed up to one of my calls with a 12" wrench I would probably make a quick judgment of them. But, as long as they can use the tool properly, I don't care what other people use.

P.S. In the debate between Gafftaper and Sean, I would have to agree with Sean that requiring 6" isn't the right approach. You should be teaching them to tighten the bolt correctly no matter what size wrench they have.
 
The worst thing posible is people overtightening things and 250 foot pound of torque is definitely in this category. The lug nuts on a typial car wheel only use 95 foot pound, many of the suspension bolts on a car suspension are less than 100 foot pound. In fact the hub nut on the drive axle is usually 145 foot pound or less. All of these fastners have to cope with both dynamic, static and vibration loads which are significantly greater than anything a stage light is likely to experience.

By the way has anyone thought of the safety issue when overtightening fastners and someone slips while attempting to unfasten one of these fastners or worse has to nresort to a cheater pipe on the end of the wrench. Has anyone actually undone a fastner torqued to 250 foot pound - I have and you usually need an air impact gun, an electric impact gun or a 24 inch breaker bar. You will not undo a fastner at this torque level using a six inch, eight inch or ten inch crescent wrench.

As has been mentioned numerous times above - finger tight plus a quarter or half turn is all that is required.

This thread started out debating the merits of C clamp rating and has explored the important issue of how tight the fastner should be that locks the clamp to the pipe but has got lost somewhere along the way. Remembering that a lot of inexperienced people read this forum we should avoid some of the more esoteric stuff.

Before we get too hung up on rating of c clamps we should also remember that much of what is hung above is not rated - I know no manufacturer provides a rating for yolk on the fixture and none of the fixtures are made from structural steel or 6061 aluminium and none of the bolts on the locking mechanisim are Grade 9. If we are not careful we will identify perceived risks in everything at a level that is unwaranted.
 
The after-effects of a 12" c-wrench.

cclamp_broke.jpg
 
Just like the saw blade showing why staples don't get used with the power saw, there's example for why not to overtighten clamps.
 

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