Lifting Slings

Because Nicks a dick?

Ya..for sure.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

For those who are new to this, one should always remember that a load will not be evenly distributed among all the chains used in a lift. If you lift a square or rectangular load with four chains (at the corners), only two chains (kitty corner) will share the entire load. The other two are only for balance. Each of the four chains must be able to support one-half of the total load weight, with a healthy safety factor.

I know everyone's sticking their two cents in, but lifting is *serious* business. It may not be apparent when things are going well, but simple failures can be catastrophic. Anything within a chain's reach is in harm's way and a chain breaking under load will go *through* soft squishy fleshy things - like people.

Regards,

Robin

I seem to remember a rather vivid Mythbusters episode in which they showed the power held in twisted steel cable, aka aircraft cable, should it fail under load. They went into an abandoned warehouse and set up a hydraulic rig to bring the cable under load and then cut it with a hydraulic shear. Then they brought in a large piece of meat to serve as the victim. While the cable didn't cut entirely through the meat, I would definitely NOT want to be anywhere near that. Even the Mythbusters crew did the entire experiment by remote control, from outside the building. I'd be that chain would be even worse, considering its weight and sectional nature. Not to mention the load itself falling rather rapidly should the chain break. ww88

That's not always true that out of four chains, only two will hold. That's so if you connected the chains to the top of the load and to a ring under the hook. If the chains form a basket, which was my case, then all four chains do the work. If the chains can slide in the hook so that tensions on each side of each chain are approximately equal, then all four chain ends will carry at least some load. In any case, even if only two chains did the lifting, that means that each chain carried a load weight of 500 lbs. Considering that they are not vertical and thus are under greater tension than the load that they support, in my case over 45 degrees, that would go up to, perhaps 710 lbs. Still far below than their rated load of 1,900 lbs.

Hard to disagree here... And remember... Even if only two chains out of four did the lifting, the remaining two are there to take over in case if these two fail.

There are many aspects to safe rigging, most of which I do not even know, but the first starting point is to always have a generous safety margin and to not be under load.

Ignoramus: Latin for ignorant.

He said that he is using chains from the hardware-store. No word about grade

See, that what you and I are talking about. But not Ignorant.

Nick

per iggy:

"That's not always true that out of four chains, only two will hold."

This idea is true under certain, rigid, conditions for example a cubical (or rectangular polyhedron) type object being lifted from each corner will sometimes pick in this manner if the 4 legs of chain are independent and not quite the same length and the object being picked has no flexibility. Additionally the sum of the lengths of one of the diagonal pairs must be less than the length of any other pairing. This condition occurs frequently in industrial lifting but is expected and compensated for, when present. Another cause of this condition is created by improper rigging and the failure to notice (and adjust for) the "short leg" occurance as it happens.

dennis in nca

That seems to be mostly about lifting things such as big transformers or concrete castings...

The only occurrence of using four chain ends going to the hook, was when I used a lifting bag type of arrangement. I made sure, when lifting, that the chains are all tensioned approximately equally.

Right - the 4-chain pick with a rigid spreader and a rigid load can end up having two of the chains with the vast majority of the weight, a third with a little bit of weight because it's slightly off center, and a fourth for all practical purposes unloaded.

But that's precisely why you allow for big safety factors, and any two of the diagonal pick points and any two of the diagonal slings or chains can handle the entire load safely with ratings to spare.

The thing that nobody has mentioned is that those two other chains or slings can't be very slack to be effective backups - you want them to be at least a bit loaded. If one of the primary pick points or chains fails, you don't want the load to get up any downward velocity before the other attachments take over.

If it does gain any velocity, the shock loading will break those other 'backup' attachment points as they try to take the load - or the shock load can overload and break the spreaders or the lift mechanism itself. And then it gets really exciting...

Even when rigging "Little" loads for a crane lift like a 3-Ton gas-package air conditioner (500 pounds) you still want to follow proper procedures. Even a "little" hole through their roof with a busted package AC at the bottom is one hole too many.

-->--

You made a great point on "slack" Bruce.

Here's a link to the army rigger's handbook TM 5-125.

One thing that is being missed here is the reference to chain rated / certified for "overhead lifting" and the fact that the lifts in question are not "overhead lifting".

There is a big difference in the risk and need for large safety margins between the chain used in an overhead crane in an industrial building that will be moving loads over workers heads i.e. "overhead" and chain used in lifting an engine out of the back of a pickup truck onto the floor.

Pete C.

Iggy, you never cease to amaze me. Thanks for this GREAT link.

Steve

Ditto!

-- Regards, Carl Ijames carl dott ijames aat verizon dott net (remove nospm or make the obvious changes before replying)

That's a good point. I will check the handbook to see just what constitutes "overhead lifting". Anything that I lift, rarely is lifted about 3.5 feet or so.

Your lies are in the fact that I did follow up to Gran't message in article Message-ID: .

I think that instead of trying to look intelligent by trying to put other people down with made up lies, you might as well become a little more humble and contribute whatever bits of knowledge or personal experence you might have, in a congenial and open minded manner.

Again, more information which is only useful to those who already know more. I do overhead lifting with loads in excess of 40 tonnes every day.

We never *ever* lift anything over someone's head, to the extent that a failure would cause the load to fall onto the person. It's illegal and exceptionally dangerous.

While lifting something only a couple of feet is *less* dangerous, a failure in this type of situation could do some very serious damage/kill someone. When chains come apart, they do it at an amazing speed. We've had chains hit the roof (4 stories off the floor) when hoist rings and eye bolts pull out of their loads.

If you happen to be standing right over a lift in order to guide it or just to take a look, you're inside the danger zone, and it's worth having some serious chain which is unlikely to come apart.

While I'm sure all this isn't news to a lot of people here, we must appreciate that there are also many who have never done this type of work and may be getting the sum total of their lifting education from this single conversation. Complete information is important.

Regards,

Robin

Humble?? Nick the Squareheaded Dick be humble?

How could he remain a proper Prussian und still be humble? Its not in his genes. Autocratic arrogance and distain..true enough..but humble?

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

So exactly where you wrote, that you are using grade 80 chains or any other variant of an certified chain?

Was it this? | That ought to be good with 5/16" chain, I think, even though mine is | indeed hardware store variety. I am not pretending to be an expert on | these issues, though.

Or did you hope that I don't know what a Msg-Id is?

I'm not _trying_ to look intelligent.

For Ignorant: By trying (failure-mode always on) to let others think you are intelligent.

Oh, I'm contributing a lot of on-topic here. But not by making a picture-series of how to replace a cable of an angle-grinder. And, while being on the angle-grinder: Even that was an Ignorant-idiotic job. The PE-cable has to be about 2cm longer than the other cables. See failure-mode above. Need more examples? How about the TIG-weld of the wrench where you claimed good penetration without preparing the welding area?

Open minded: Is is that, where your brain fell out? Or do you mean your OT-posts by open minded?

Nick

"Ignoramus29782" wrote

You never cease to amaze me. If you're ever going to be in Las Vegas, I'll let you know how to get hold of me, and I'll buy you an adult beverage.

Steve

That's always a good precaution when it's possible, but certainly isn't possible in a huge number of work environments.

That's utterly absurd. Loads are lifted over workers heads every single day in hundreds of thousands of places. It is most certainly not illegal and is indeed necessary and unavoidable in most of them.

A chain that fails under the maximum load that any HSM person would ever be likely to place on it, perhaps 5,000#, simply will not do that much damage, there just is not enough energy. Your 40T loads have several orders of magnitude more potential energy stored in chain stretch than you can ever get with a measly 2.5T load.

If you are working with 40T loads sure, a 1,000# load a couple feet off the ground on an engine hoist is not even remotely close to the same risk. The only appreciable risk for that 1,000# load on the engine hoist is a crushing injury if the load is dropped or tips. A chain break simply won't have the energy to do more than give you a bruise.

Complete information is important, paranoia is not. Paranoia over unrealistically inflated hazards like breaking chains can lead to overlooking the real hazards of the particular lift such as the loads CG and the stability of the engine hoist which are the actual significant hazards faced in any likely HSM lift.

Pete C.