On Fri, 26 Mar 2004 15:55:24 -0800, RainLover
vaguely proposed a theory
.......and in reply I say!:
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I've been looking at chain lately (3/8") and I've noticed something that so far, every hardware guy
says he's never seen before. On the box of chain, without exception, they all say "DO NOT use for
lifting or any situation where a life could be endangered if the chain fails.

Tell me if I'm wrong here, but what in the hell could a person use a 3/8" chain for that wasn't
potentially dangerous. If the chain has a rating of 6,500 pounds and breaks, someone is going to be
around!!!

Is this a case of lawyers being in charge of chain-making or is there actually different chain that
is approved for lifting and all the stuff at H.D., Lowes, Ace is made for something else... what I
don't know.

Any suggestions? :-)

Very complex. And I cannot supply the full result. I am not quite sure
what differentiates lifting chain from towing chain. I frequently
ignore the two....but that's my risk.

But to answer your question(s) Yes. Simple towing. Yes, but their risk
is variable.

No and Yes.

Now to the rambling, personal experiance BS. All usual disclaimers of
a complete lack of competence to explain this situation apply.....

3/8" chain in the hardware store is not very strong. It's probably not
much above mild steel, anf they probabnly include the galv in the
diameter. Its _breaking strain_ may be a couple of ton. It's not
tested. It should only be used for some amount less than that, and in
situations where the failure does not matter.........eg not for
lifting. You cannot use the tensile strength of 3/8 steel to asume its
strength. Welds, angles shapes.....messy....complex. It is basically
not _guaranteed_ to do _anything_ besides be there.

Interestingly, if the _brain_ is applied (ratings never assume this)
soft steel is "safer" than HT steel. It sags then tears. HT/spring
steel resists then lets go.

OK. back to hardware chain. I use it for none of my work above hanging
pot-plants. For anything else I get rated chain and couplings. They
serve me, although I abuse them, and the warnings that I get when I
buy them, to a point that renders anything but self-employment
illegal. In short I behave like most farmers. G

SORRY. I HAVE TO DO THIS. I DIGRESS.

Here I will interpose a story. I was buying a piece of gear. The
seller needed to remove another piece of gear, tractor-towed, to allow
testing of the bit I wanted. The PTO shaft of the bit I wanted got in
the way of moving the other bit. "Hold this out of the way" he says. I
was not happy, but tried to be a "nice guy". So he starts to drag the
other piece out, behind 100HP of cabined tractor, and I am caught
between the gear I want to test (2 tonne +) and the approaching piece
of steel flotsam trapped behind the 100HP tractor. I yell. I scream.
Of course he cannot hear me. It passes me by with A 2" gap (which was
full of smelly brown matter!) and I escape without injury.

WHEN WORKING WITH MORE THAN YOURSELF, THE DANGER INSCREASES AS THE
CUBE OF THE NUMBER OF PEOPLE INVOLVED.

WHEN ON YOUR OWN AND WORKING WITH MACHINERY, WORKPLACE HEALTH AND
SAFETY IS NOT SOME (S)MOTHERING GOVT DEPT! It's your brain! perfection
is the norm.

OK Digression over......SORRY.

One of the things about chain over cable is that chain simply breaks.
It does not stretch much first, or if it does, it is _largely_ by
non-recoverable deformation of the steel in each link, which will not
restore and supply recoil energy. I have seen this in action, by
breaking chains. They simply snap and sit there.

Cable has windings that 'wind up" and allow the cable to store
enormous amounts of energy before breakage. They are high tensile
steel in direct tension...another source of stored energy.
- Good point? It frays first, then snaps.
- Bad point? When it goes, after you have ignored the warnings, it
can let go many horsepower/seconds of stored energy in your direction,
along with whatever is attached..
- Cables would bury an arrow in you if they could. I have read of
someone's head being taken off by a vehicle's towball.

To give you an idea, get a bit of rated lifting cable and unravel it.
Now wind the spring steel back up. Over several metres you are storing
a lot of energy.

However, when I buy chain, I am always warned that it is drag chain,
not lift chain. AFAIAA, the difference is not in behaviour, bu rating.
EG Drag chain will break at 3x its rated strain. Lift chain needs at
least 5x. There are complexities there. As other have said, hooks come
into play, so that they bend first. etc etc.

I simply never set in the way fo a stressed element of what I am
doing. If I do I am dumb.
************************************************** ** sorry

..........no I'm not!
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