On Feb 11, 12:16*pm, "D. Peter Maus" wrote:
On 2/11/11 13:22 , bpnjensen wrote:









So, a mechanical question this time -

On a relatively short run of wire of fairly light weight (in this
case, 14 gauge stranded, insulated, and about 60-65 feet horizontal),
what's a good estimated counterweight for the far end? *The wire
itself is light, but the counterweight needs to account for tension as
well. *The support line is over a freewheeling pulley and is currently
tied off, but I think a modest eight would be better in this
circumstance as the near end of the line is a treetop with some sway
in the wind.

So, I ask if anybody has an idea about what a good weight night be to
maintain tension and avoid too much sagging. *For starters, I was
thinking a simple barbell weight of 5 lbs or so more or less, but I'm
wide open on this one.

Thanks so much!
Bruce

* *Weigh the wire. The counterweight will find a balance with the
weight of the wire, allowing an amount of sag equal to the length of
the counterweight support. Doubling the counterweight will halve the
amount of sag. Redoubling will halve the sag, again. Don't exceed
the tensile strength of the wire and start with about 4 times the
weight of the wire.

Well, the wire's already up there - but I don't think the whole roll
weighed but a couple pounds, and this is about 2/3 of the roll in the
air (maybe 65 horz feet). So, maybe something like 8 pounds will be a
good starting point. Water in any mass doesn't really freeze here (at
most we get thin ice on the birdbath, and then only about 5 or 6 times
a winter), so that gallon jug of water would be a good starting weight
-

IIRC, the tensile strength of 14 gauge wire is pretty high, over 100
lbs - isn't that right? So any reasonable weight (like less than 20)
is not liable to break it.

Good ideas, Peter and Roy and Dave - thanks.