On 12/29/2008 jimlux wrote:
> K7LXC@aol.com wrote:
...snip...
>> But the even simpler solution is to use nylon slings. I always carry
>> 6-8
>> of them when I'm doing tower work and sometimes I use all of them. They are
>> 1" nylon webbing that's sewn together giving you an endless loop 12-18"
>> long.
>> You just put it around the object of interest once or twice (for heavy
>> loads
>> I'd recommend at least twice) and pull it thru the other end of the loop.
>> Put some tension on it and you're good to go. The more you pull it, the
>> tighter
>> it gets. All you have to do to release it is un-weight it. In the parlance
>> it's known as a choker. Champion Radio Products has them and you can buy
>> them
>> at REI - look in the climbing hardware department near the carabiners.
>>
> probably a bit pricey for a one shot deal, but maybe you know someone
> who has them.. soft slings are even nicer (they're a tough fabric tube
> with unwoven fibers inside).. think of kernmantle rope with a very loose
> sheath. They're great because they "squish" out where they cross over an
> edge or something, and they're really abrasion resistant (for the same
> reason as kernmantle climbing ropes)
> Also called Spansets
> http://versales.com/ns/sling_webbing/span_sets.html
> page 1450 in the McMaster-Carr catalog
OK - I was never a licensed rigger (disclaimer), but did a BUNCH of years of
rigging all sorts of stuff (my foreman WAS licensed)
A nylon sling is great - but not really what _I_ would want for a VERTICAL lift
of a piece of pipe/tube, but also would not be bad (I always worry about nylon
slipping, but if you do it up like a prussic...)
This is one of those places where a GOOD natural line (hemp etc) works well,
and you have an eye in the end to go to your gin poles lift line
The proper knot, at the balance point of the load is a clove hitch, tied in
such a way that when you pull to the side that will be "up" it tightens the
knot - you then put a half hitch on the top of the load, again, where the
weight tends to choke the load - the load goes up straight, and when you get it
in place, the rope just comes loose
My rigging was not at the heights that big towers were, but I've lifted lots of
BIG pieces of steel between 10 and 100 ft (heaviest lift just over 10 tons - to
35 ft)
--
73 de KG2V
For the Children - RKBA!
You Are, What You Do, When It Counts - The Masao
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