Can someone tell me why

[itlightsup]

I would choose this:

12 inch Mega Truss Pick, 1 ton (mega truss pick 1 ton)

over this:

http://www.ia470.com/primer/motor.gif (typical box truss wrap)

In terms of stabilizing the truss of torquing or movement while hanging/focusing.

I understand the mega clamp allows a secondary straight down rigging point, but again, couldn't a second down wrap accomplish *about* the same thing?

Cheers

[danTt]

Hi,

My two suspicions (IANAR):

1) Looks. If this truss is going to be in view of the audience, it looks much nicer than a spanset choked to the truss.

2) Distance. You can get the motor a lot closer to the truss with this setup, which becomes important when you are dealing with low ceilings and motor limits. If you choked a spanset enough to get the point parallel with the truss, the loads on the spanset would get strange, and I'm not entirely sure the spanset is rated any more.

[itlightsup]

Looks I can definitely understand; we were considering hang this motor the hard way for just that reason.

But with a short spanset, two wraps, the triangle at that point can be anywhere from 1.5' to .5' above the truss, which to me doesn't seem that imposing.

The only thing that worries me about the load on the spanset is the instruments not being hung with proper weight distribution and pulling one side or the other too much.

[metti]

The truss pick products deal with trusses that are hung at weird angles or weird loading better. Also, it is slightly faster to tighten one of those to a piece of truss than it is to wrap spansets on to it.

[Pie4Weebl]

I swear by truss picks, when you're trying to get a truss up in a room with super low ceilings every inch counts! It looks for much cleaner too.

[Dover]

But with a short spanset, two wraps, the triangle at that point can be anywhere from 1.5' to .5' above the truss, which to me doesn't seem that imposing.

On a 2000lb pick the compressive force on the top cord of the truss with a 1/2in high bridle is about 24,000lbs. That is why you do not set a spanset that tight.

[Footer]

Those things are useful if you need them. You won't see any out on 120k rigs or R&R gigs. However, if you are concerned about looks and trims it is really the way to go. Otherwise, a span set is the way to go. I would not go out of my way to use them unless I had to.

[spribil]

You also don't have to worry about these "melting" or getting torn up, and easier to see if it was put on "correctly." I would not think a safety cable would be needed for these?

[avkid]

You also don't have to worry about these "melting" or getting torn up, and easier to see if it was put on "correctly." I would not think a safety cable would be needed for these?

Steelflex won't melt either.
Lift-All® SteelFlex Roundslings

[spribil]

With Steel Flex you still have to worry about the polyester jacket. With the clamp you don't need a unique inspection window allows for easy inspection of the core for broken wires and corrosion.

[tprewitt]

Round slings are ok I guess but I don't know what the manufacturers say about using them for long term installation (or overhead lifting for that matter). I suspect they don't.

10 or so years ago Trey Allen at JTE (very knowledgeable and funny man BTW) asked me to consider the safety/installation/engineering differences between a truss clamp and a round sling and then asked me if I really gave a s*!^ about the little bit of extra cost. I concluded it was better, and I didn't, and I haven't used a round sling on truss since.

[ruinexplorer]

On a 2000lb pick the compressive force on the top cord of the truss with a 1/2in high bridle is about 24,000lbs. That is why you do not set a spanset that tight.

Who said 1/2 inch? The distances were 1.5 feet down to 1/2 foot. I still agree that six inches is an extremely tight bridle and would defer to the other product in that instance.

The other benefit to choking a roundsling as shown in the second picture is that the load on the truss is under compression, taking some strain off the welds of the truss. I know that there has been debate on the necessity of this, but should you choose to use the pick point, you do not have this option. Also, a roundsling is never used by itself, it must have a steel safety. That safety can be internal such as avkid linked, or a secondary device. After all, a PAR64 with a 1K lamp can melt a roundsling (watched it happen in a demonstration).

[derekleffew]

...The other benefit to choking a roundsling as shown in the second picture is that the load on the truss is under compression, taking some strain off the welds of the truss. I know that there has been debate on the necessity of this, but should you choose to use the pick point, you do not have this option. ...

Any reason one can't use the truss pick pictured on the bottom chords "under" the truss?


Here's a similar product with an added feature:

Tyler Truss Adjustable Pick Point - YouTube

[gafftaper]

I think an important point to consider is your need and are you thinking in terms of upgrading existing equipment or adding new equipment? If you already have the gear, there really isn't a very good reason to replace it other than to have a new toy. However if you are buying all new gear anyway, then there isn't a lot of cost difference and so the new product that does the job in a more elegant way is a lot more appealing. Many of the products made by The Light Source fall into this classification. You already have a widget that does the job just fine. The new widget is cool and handles the task in a clever way, but you just can't justify the cost of replacing your old widget. However, the next time you are going buy some new truss to hang (or have to replace a damaged spanset), you might find yourself adding a couple new mega truss picks to the order instead.

[ruinexplorer]

Any reason one can't use the truss pick pictured on the bottom chords "under" the truss?

When you use a roundsling, looped around the bottom and spanning the top (as pictured), you get less roll with an unballanced truss load. This is even more evident when you add moving head units to your truss, especially if you also have projectors on the same truss. Too much movement for fine focus of front projection. Not as bad with scanners.

The video provided, with the added feature is pretty cool.

[gafftapegreenia]

Also, a roundsling is never used by itself, it must have a steel safety.

I think a lot of tours currently on the road would disagree. Then again it seems most people are using GACflex these days.

[ruinexplorer]

If any tours are using a roundsling without it being GACflex or a secondary steel safety, then they are grossly endangering anyone who passes underneath the truss. I have seen video of movers catching fire, possibly ingition of dust particles in them. No matter the cause, had the truss been supported only by a polyester roundsling, there could have been a catastrophic failure. Under no circumstance should a roundsling be used for overhead lifting without a steel safety system. At only a little over 190 degrees Farenheit is a roundsling rendered useless.

[DuckJordan]

Then every tour that's come through my space is endangering their performers and crew... Many of which are broadway, Union, Equity shows...

[ruinexplorer]

Something else you can add to your facility contract. My fire marshal would never have allowed it since it is an extreme hazard for emergency crews if nothing else. They don't need to worry about the structure falling even with a minor fire.

[mstaylor]

And I was told by the truss company that a steel sling will cut a truss in half if it fell on it. What I have had some companies do is hang a xsecond point beside the hoist as a safety.

[ruinexplorer]

I would be interested in seeing hard results on truss being cut in half due to the shock load of it being a safety (which truss company told you this?). As I stated, I have seen first hand the failure of a roundsling when a PAR can was pointed at it (note, no open flame, just the heat from a lighting instrument). Would we trust plastic bolts to hold our lighting instruments and other gear without some sort of steel safety measure? I doubt that any of us would want to walk under that rig if we knew.

I am willing to be proved wrong on this matter. However, we need to tread carefully and only present facts and not opinions. Even if we see others doing something that is wrong by industry practice and they have no problems with their hang, does not make it a safe practice. I have a former colleague who works for one of the major truss companies. I will contact her as well to see if we can get a better estimate of good practice.

[egilson1]

couldn't a second down wrap accomplish *about* the same thing?

Cheers

From a load transfer standpoint, this is not the same. When you wrap a truss with a sling to the suspension device and then wrap it for a pick point for something hung below, you are applying a shear force to the cords of the truss. With a lift point like these, that force is transferred directly to the suspension device.

Regards,
Ethan