rigging (UK lantern clamps)

[kiwitechgirl]

Can you safely hang those UK clamps on a vertical pipe?

Parcans of any size, flood/cyc units and 650w fresnels/PCs, yes. Anything heavier than that, I don't tend to - but I have seen it done. I've never found them to be flimsy and haven't had trouble securing them - as I said, there's also less chance (in my brain, anyway!) of them slipping off the bar if some idiot does fail to do the clamp up properly than there is with a C-clamp. Gafftaper, maybe I should send you one of our clamps so you can try it for yourself! I've not used the C-clamps enough to be able to do a proper comparison - they're so seldom used here, although I think there are a couple kicking round in our tech store for some unknown reason!

 

[TimMiller]

Based on what yall are saying, the clamps that we get like you have are much more flemsy. I have bent them with my hands, but thats some cheap chinese knockoff. Using a piece of bent steel like that can support a lot of weight. We bend metal all the time at the shop for projects and have never bent anything, except for a CD-80 frame..........

 

[derekleffew]

...But, although I've heard rumors here on CB of them breaking, I've never seen or hear stories from any friends of a cast iron c-clamp breaking. ...

I'd like to think you consider me a friend !, and I have personally witnessed a cast iron C-clamp break--the result of over-tightening an overhung PAR64 on 1.5" BIP, by an IA stagehand with an 8" adj. wrench.

 

[Sean]

Oh yeah...

I've not had a clamp fail at a critical moment...yet...but I'm convinced it's just a matter of time. I've seen maybe a dozen or so broken clamps in the past ten years.

Cast clamps are brittle. They're also really not the best kind of hardware to use on booms. Yes, we all do it...but that doesn't mean it's a great choice. Budget allowing, I've been trying to reduce my reliance on cast clamp sidearms. Tees aren't an issue as they see very little force (as compared to their size), but go take a look at your older clamps. I'll bet you see that they're stressed/twisted/stretched a bit.

As for the UK, I know one of the pieces of hardware use as a sidearm is a piece of flat bar with a 90 degree twist. It's clamped the the boom, and the twist allows the fixture to be through-bolted to a hole in the end of the arm.

--Sean

 

[gafftaper]

So in the end this thread ends up as an ad for those clever people at The Light Source. Heavy duty extruded aircraft grade aluminum. Not bendable like the UK clamps and teeth to grip. Not fragile like the US clamps and most don't have an "F-nut" to break off. I own several of their mega claws, mega drop downs, and mega baby side arms. I Don't own any of their c-clamps but I've seen them in person and they look like excellent products.

I also believe they are the only product that has a safe working load rating. I've seen some cast iron clamps that have 500lbs stamped on the side but I've always been suspicious of the that number.

I'd like to think you consider me a friend !, and I have personally witnessed a cast iron C-clamp break--the result of over-tightening an overhung PAR64 on 1.5" BIP, by an IA stagehand with an 8" adj. wrench.

Well some friend you are. You never told me about it. That's one more vote for my 6" wrench rule.

 

[kiwitechgirl]

I also believe they are the only product that has a safe working load rating. I've seen some cast iron clamps that have 500lbs stamped on the side but I've always been suspicious of the that number.

All our hook-clamps are stamped with an SWL of 50kg on them...you can probably buy cheap Chinese variants that don't, but get them from any reputable manufacturer and they're rated

 

[2manydjs]

I'm in belgium and I use this kind of clamp for automated lights

but for par/profile/pc/4-bars I use those ones.

 

[church]

when I started doing lighting in the U.K back in the seventies the only choices I ever saw for hanging a ficture (lantern) was to use the clamp shown in the pictures made from bent steel or to use a bolt through a hole in a pipe or steel bracket. we hung the Strand Patt 223s and patt 243s using these clamps. After all the clamp was made from thicker steel than the yoke hanging the fixture itself