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Author Topic: Truss Bases update .....  (Read 1319 times)

Jeff Lelko

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Re: Truss Bases update .....
« Reply #10 on: January 13, 2020, 04:52:19 pm »

Prolyte published an interesting mini-article about the liabilities of mixing different brands of trussing.  Granted they are a European company and thus the laws are different than in the United States, it's still an interesting article that's applicable in practice to any truss user, regardless of location.

FAQ - Can I combine with other truss brands that say they have ďProlyte compatibleĒ truss?

I own a small bit of their Verto Truss which I love for its speed and simplicity, but compared to Global Truss it's very limited in assortment at triple the price.  I'd love to make some adapters that allow Verto Truss spans to be used with Global arches or corners, but that will require some very careful engineering in addition to my taking on full liability for the setup.

My takeaway from the Prolyte article is that regardless of brands, whenever you advance beyond the Guitar Center prepackaged trussing kits you take full responsibility for the viability of the structure you create.  Tying in with the ongoing Ankle Biter thread, you as the operator will be held liable in a mishap regardless of the kit you use and need to have insurance accordingly...it's just that buzzwords such as criminal negligence now become involved when it's your own creation that failed due to inadequate structural engineering/analysis.  I have a number of custom-fabricated components in use in my rigs and am very comfortable with them.  They've had the necessary guidance from the appropriate entities to ensure that they'll work as intended, though at the end of the day the liability is still mine to undertake. 

Circling back to this thread, yes, Joel is using a couple of custom-fabricated mounting solutions.  Should such a creation fail, Global Truss would likely not accept any liability since their equipment was being used beyond of the scope of its intended application.  That said, Joel can still do the appropriate homework such as obtaining a shear SWL for the clamps and bolts, and ensuring that he stays within that limit plus a margin of safety.  It still won't absolve him of any liability should it fail, but it will show that the proper engineering effort was made to prove the viability of the structure.  As always, consult an attorney for proper legal advice...               
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #11 on: January 15, 2020, 09:39:50 am »

Thank you to all for the replies. I'll address them one at a time. It might take a few days, but I'll get there.


The 1/2 conical couplers for base plates that Global sells do not have a locating pin, and already have 10 mm x 1.5mm internal threading. That would have saved you the hex nut and grinding down the locator pin on one of the two pieces.   You would still need one of the UJB pins (with locator pin) in order to get a connector counter-bored for the socket head ("Allen") cap screw.

If you don't already know about blue Loctite (# 242), now is the time to find out. Loctite is an anaerobic thread adhesive, which cures in the absence of air (when threaded together). Blue Loctite (also sold by other brands) is removable with ordinary hand tools.  Red Loctite, on the other hand, is not readily removed. (It usually takes heat as well.). An assembly threaded together with blue Loctite will not vibrate apart or otherwise loosen from mere use.

As much as I try to shop locally in my small town (30,000 pop), McMaster-Carr is a good source of specialty fasteners. They are on the web, and often sell fasteners in less than a box of 100. MSC Direct is another good source.

Good luck with your endeavors.

Edit: correct thread size to M10

Thanks Mark.

I needed one piece with the threaded hole - https://www.idjnow.com/global-truss-half-conical-coupler-for-f31-f32-f33-f34-f44p-series.html and one that is hollow, so that a bolt can be inserted. Like these - https://www.idjnow.com/4-global-truss-universal-junction-couplers.html. If someone makes this second piece without the tit, I couldn't find it. No big deal, as it took all of about 10 minutes to cut the tit off 8 pieces. I used a cutoff blade and my angle head grinder.

Yes, I've been using Loctite for years. Great product and very handy in SO many projects that I work on.
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #12 on: January 15, 2020, 09:46:45 am »

These look great Joel, thanks for sharing!  I definitely like the look of what you built compared to the usual box truss straddling a pair of tripods...not to mention the ability to uplight as well.  These look solid, stable, and professional.

Mark is correct - the half-couplers made for baseplates donít have that pin on them (which then makes them a bit of a pain to get oriented correctly), but itís something to keep in mind for future purchases.  Also, just make sure you socket head screws you bought are of sufficient strength.  I know that both Class 8.8 and Class 10.9 are commonly found in trussing, though Iím not sure which Global prescribes for use in these connectors (I always double-check when buying inventory and donít want to accidentally misspeak).  Glad to see it all worked out for you!

Thanks for the compliment Jeff. I appreciate it.

I addressed the couplers in the previous post.

The bolts I bought are in fact rated at 12.9. I scoured the big box store and the internet to be sure that was the strongest bolts I could get in that size/configuration. If there's something stronger out there, I can't find it.
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #13 on: January 15, 2020, 01:10:28 pm »


Those cheesborough clamps are not designed to hold the load attached like that.  Need to use truss adapters for the top of your stands.

Thanks for your input Scott.

I have no doubt that you have more experience with this sort of thing, (in the lighting world) than I do, so please take this with all due respect.

While I'm not a structural engineer, I have been building steal, wooden, pvc structures and repairing/customizing farm and heavy equipment for many years. I am very aware of public safety and possible litigation. Someone mentioned consulting an attorney: Believe it or not, but I'm married to a prosecuting attorney. I can't get away with jack!! LOL Not that I try, but you get the point. I do consult with my wife on projects that might involve legal ramifications.

While I understand and agree with you that these types of clamps (like I built for mounting i-beam truss to my medium duty tripod light stands) aren't necessarily designed or normally used to support a horizontal load, I'm going to say these are much stronger than the plastic clamps that one finds on the cheap, dj type goal post packages. Or any of those types of packages that I've looked into.

Now my goal of course, is NOT to build with the lowest common denominator in mind. But I'm also not designing this to support a ton of weight either. My plan is to hang 4 to 8 LED PAR lights from this truss. And more than likely, when the i-beam is mounted on the tripod stands, it won't be more than 4 meters long. The combined weight of the truss and 8 LED lights will be somewhere in the neighborhood of 50 pounds. And that weight will be spread across 4 clamps/bolts.

From Global Truss' website, the max load capacity of their Jr Coupler Clamp, designed for F23/F24 truss, is 165lbs. Times 4, that is 660lbs. Even if I figure the SWL of a horizontal hang is 1/4 of the vertical load capacity, we're still looking at 165lbs. Not a tremendous amount, but more than I need. Now, while I'm not using Global's Jr clamps, the ones I assembled from their parts are very similar.

I built these clamps with bolts that have a class 12.9 hardness rating. As far as I can tell from my research, that's what Global Truss uses for similar types of clamps.

A 10mm bolt with a class 12.9 rating, while not very big, will hold a tremendous amount of weight, as long as it's kept tight. When it becomes loose and things are able to move, is when it can and eventually will sheer. Hence the need to Loctite.

I haven't been able to find a truss adapter for i-beam truss. If you, or anyone knows where I can find such a product, please post a link and I'll definitely look into that.

As Jeff said in an earlier post ......

++++++ DISCLAIMER!! - Always Consult the Equipment Manufacturer for Appropriate SWLs and Applicablity to Intended Usages ++++++

++++ I'm not advising anyone to build these types of kit without doing sufficient research and consulting manufacturers. Do so at your own responsibility and risk! ++++
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #14 on: January 17, 2020, 02:31:47 pm »


........

All of that said, YouTube is generally never a good source when building DIY structural solutions...  Iíve got a folder of bookmarks to show why my insurance goes up every year!

I can't disagree with you here Jeff, I've seen some pretty questionable diy projects out there. But I've known Brian for many years and he's not some fly-by-night hack. I really only referred to his video, because that's where I got the idea of putting together my own custom clamps.

Thanks for your input on this. I do appreciate it.
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #15 on: January 17, 2020, 02:42:14 pm »

Joel,

Your project has answered a question I had about mixing and matching box and I beam "euro" style truss. Thank you.

Perfect. That's the reason I posted here.


If you decide to add a second pair of corners to your rig, you might consider using the Universal Junction Block ("UJB"). You could have the UJB ever so slightly modified to allow the locator pin to be offset 45 degrees so you could align with either the I beam or the box truss holes.  A machine shop could add a second alignment spot on the UJB faces with an end mill (to give you a nice flat-bottomed blind hole).

The UJB is only 290 mm wide, vs. the 500 mm length of the 90 degree corners, so that's something to keep in mind if you try that idea at some point.

That would be another possibility.

I'm positive I've seen the UJB type box with multiple alignment holes, but I can't seem to locate it now. This would allow one to turn the 1/2 conical enough to line up the pin holes on the i-beam truss.

What I've assembled will work for what I'm doing now. If/when I get to the point that I need to rethink/redesign this, I'll keep other possibilities in mind.

Thanks for your input on this thread Mark. Appreciated.
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Joel T. Glaser

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Re: Truss Bases update .....
« Reply #16 on: January 17, 2020, 02:54:03 pm »

Prolyte published an interesting mini-article about the liabilities of mixing different brands of trussing.  Granted they are a European company and thus the laws are different than in the United States, it's still an interesting article that's applicable in practice to any truss user, regardless of location.

FAQ - Can I combine with other truss brands that say they have ďProlyte compatibleĒ truss?

I own a small bit of their Verto Truss which I love for its speed and simplicity, but compared to Global Truss it's very limited in assortment at triple the price.  I'd love to make some adapters that allow Verto Truss spans to be used with Global arches or corners, but that will require some very careful engineering in addition to my taking on full liability for the setup.

My takeaway from the Prolyte article is that regardless of brands, whenever you advance beyond the Guitar Center prepackaged trussing kits you take full responsibility for the viability of the structure you create.  Tying in with the ongoing Ankle Biter thread, you as the operator will be held liable in a mishap regardless of the kit you use and need to have insurance accordingly...it's just that buzzwords such as criminal negligence now become involved when it's your own creation that failed due to inadequate structural engineering/analysis.  I have a number of custom-fabricated components in use in my rigs and am very comfortable with them.  They've had the necessary guidance from the appropriate entities to ensure that they'll work as intended, though at the end of the day the liability is still mine to undertake. 

Circling back to this thread, yes, Joel is using a couple of custom-fabricated mounting solutions.  Should such a creation fail, Global Truss would likely not accept any liability since their equipment was being used beyond of the scope of its intended application.  That said, Joel can still do the appropriate homework such as obtaining a shear SWL for the clamps and bolts, and ensuring that he stays within that limit plus a margin of safety.  It still won't absolve him of any liability should it fail, but it will show that the proper engineering effort was made to prove the viability of the structure.  As always, consult an attorney for proper legal advice...             

Thank you Jeff, for sharing that very informative article.

I guess what it boils down to for me, is to ALWAYS understand how your equipment was designed to be used and what it's capabilities are. And just as importantly, if not more so, carry good liability insurance. In this crazy ass world we live in today, you can't be too careful!

I had recently watched a video on that Verto Truss. That would be great to have, if it wasn't so expensive! I'd have to charge way more than my normal client can afford, to justify the cost! But hey, you never know. Maybe somewhere down the road.......
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Jeff Lelko

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Re: Truss Bases update .....
« Reply #17 on: January 17, 2020, 03:33:00 pm »

The Verto Truss is an excellent product, albeit at a professional price.  I use it for a very specific aplication that requires orientation-agnostic connectors...unlike the Global Truss couplers that only work in one specific clocking.  The tool-free and silent assembly are time-saving bonuses as well.

I've learned some good tricks from YouTube as well, though more often than not the eye-opening videos of sketchy rigging are more for entertainment value.  As mentioned above I also use some custom-fabricated components throughout my rigs.  When dealing with anything load bearing, context is always important.  The question of "what happens if..." is also much different when deploying a minor assembly at the back of a stage versus hanging thousands of pounds over people's heads...and should influence what's acceptable accordingly.  Glad your solution is working!
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John Fruits

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Re: Truss Bases update .....
« Reply #18 on: January 27, 2020, 03:22:41 pm »

Just as a sidebar concerning truss bases here is another company that makes truss bases:
https://www.entfab.com/
They do have some interesting items.
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Mark Cadwallader

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Re: Truss Bases update .....
« Reply #19 on: January 27, 2020, 06:18:29 pm »

Just as a sidebar concerning truss bases here is another company that makes truss bases:
https://www.entfab.com/
They do have some interesting items.

Thank you for that reference. Looking at the specs, I wonder whether they would need modifications to work with "euro truss" products.  FYI, the spec sheets for different sizes of their base products don't appear to necessarily track with actual weights and dimensions of product.
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Re: Truss Bases update .....
¬ę Reply #19 on: January 27, 2020, 06:18:29 pm ¬Ľ


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