Non standard clamps

[Pattern123]

I'm going to risk getting another lot of pedantic lectures I'm sure, but I have another little problem, and just wondered if anyone has any bright ideas.

 

As part of a refurbishment of our performance space a balcony has been built along the rear wall, which is nice! However, in spite of several meetings with the powers that be and giving a written spec asking for the handrails to be 48mm Scaff size, to make it nice and easy to clamp onto, and even to rig lights directly onto (We requested an extra rail above head height as well) the Architects/Engineers have managed to make it 42mm - which is just too small to safely clamp onto.

 

I need to attach an IWB to the upper rail, and I was wondering if anyone had any bright ideas as to a clamp that might do the job 'off the shelf' rather than having to get special Universal Brackets made by Doughty.

[rossmck]

Personally I'd be reluctant to risk hanging anything off a hand-rail... not least because there will be no SWL for it although I've seen it done on many occasions.

 

Try a few scaffold companies, as far as I know 42mm is a (slightly less common) size of scaffold tube, and as such there will be clamps available for it (you can certainly buy the tube easily enough) - perhaps using a 42mm clamp coupled to a 48mm clamp would allow you to achieve what you're trying to do.

 

If you do go down this route, please at least ensure a secondary suspension method is used as well.

 

I would strongly suggest, however, that you just have the IWB professionally installed (and load-tested) rather than attaching it to something that was not designed to hold it with clamps not designed for the purpose. Alternatively if it's only for a couple lights I'd be more inclined to hang them directly off the bar (again, this should only really be done if you have an SWL for it!) rather than adding the additional weight of the IWB also.

[Brian]

I've used 'odd' sized hook clamps before to hang off smaller truss. IIRC Powerdrive do some.

[Pattern123]

Yes, just to clarify, it's a little more than just a handrail, the railings are structural, and the whole thing is so over-engineered, you could sling the QE2 underneath it quite safely, so there's no issue attaching the IWB to it. It could attach on the front, or sit on top of the structure, which is probably easier, in which case the clamps/brackets would just be holding it in place & preventing it rotating. I have installed plenty of IWB's over the years and am fully qualified, so no issues there, just wondered if anyone knows of anything off the shelf. I will have a look at scaff clamps cheers.

[djw1981]

Having architects / engineers around is a useful time to get the official loading or anything you may ever want to rig from provided under the design contract and not have to get stuff assessed further down the line.

[Modge]

CPC do some smaller hook clamps - ST00945 for one (though that is a slightly unusual looking beast). I've used some from them before that are simply the same as normal clamps but smaller, so look around the catalogue for others.

[rossmck]

Yes, just to clarify, it's a little more than just a handrail, the railings are structural, and the whole thing is so over-engineered, you could sling the QE2 underneath it quite safely, so there's no issue attaching the IWB to it. It could attach on the front, or sit on top of the structure, which is probably easier, in which case the clamps/brackets would just be holding it in place & preventing it rotating. I have installed plenty of IWB's over the years and am fully qualified, so no issues there, just wondered if anyone knows of anything off the shelf. I will have a look at scaff clamps cheers.

 

Ahh that makes much more sense then : )

 

Forgive my initial reply, but you can imagine what I picture when I hear the expression "handrail" ;-)

 

I'm fairly sure I used smaller clamps for something on truss once before as well, they were attached to lights hired by the company that hired me the truss though, but I'll see if I can find out what they were / where they were from :)

[dbuckley]

Your local while-you-wait exhaust joint will have exhaust clamps available in a bewildering array of sizes.

 

Clamps + Dexion = Job Done.

[tony g]

A smaller standard hookclamp was once popular, particularly used by Furse it would probably fit the bill, try Jim Laws lighting, Jim's the master of the obsolete, odd and weird kit. Failing that get a local smithy to close up a standard hookclamp and re-temper it - it's a very small job for a well equipped metal fabrication shop.

Assuming your rail will take the load!!

[Bryson]

American-style clamps have the advantage of being adjustable to different pipe sizes. (Although there's a lot of other things wrong with them...)

 

http://i347.photobucket.com/albums/p456/derekleffew/C-ClampParts.jpg

[boatman]

CPC do some smaller hook clamps - ST00945 for one (though that is a slightly unusual looking beast). I've used some from them before that are simply the same as normal clamps but smaller, so look around the catalogue for others.

 

Be careful with CPC hook clamps. None of the ones I have are marked with a load rating. This may not be acceptable if you have rampant safety elves in your venue

[Malcolm Gordon]

42mm corresponds to Size 7 Kee Klamps, which have a great variety of fittings. Some require sliding onto the tube, others can clamp to an existing tube, in particular the Type 17 Clamp-on Crossover. We use Kee-Klamps for a variety of stage structures.

[Pattern123]

Thanks for all the suggestions, for the record, and in case anyone else comes across the problem, standard scaff clamps actually fit both sizes of tube, so looks like it will be nice and easy after all!