I got some of those short-saddle ones from Hill Radio one time
when I ordered the Rohn part number. I didn't like them either.
Recently I got some from Texas Towers, and they have deep
saddles. I don't know if they are hot-dipped or plated,
malleable or forged, and I don't see any ridges in the saddle,
but at least the two wires lie correctly together within the
saddle.
Dave Hachadorian, K6LL
Yuma, AZ
-----Original Message-----
From: Donald Chester
Sent: Sunday, June 7, 2015 12:56 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Guy Wire Cable Clamps
It's tower and antenna season once again.
For tower guying I prefer Big Grips, but for some applications I
still use old fashioned cable clamps, for example, to attach guy
wires to ground anchors, allowing for easy re-adjustment as
necessary, months or even years after the initial installation.
Another is for strain insulators and other hardware whose contour
won't allow it to fit snugly against the U-shaped bend of the Big
Grip. An engineer at PLP verified that this has caused failure,
particularly with offshore manufactured strain insulators. He
strongly recommended against using Big Grips for such
applications, knowingly discouraging potential sales.
For a recent project I ordered a bag of 3/16" clamps from Rohn
through one of their distributors, under the same part number as
listed in the Rohn catalogue. Originally, these were part # 3/16
CCM, but the Rohn catalogue now lists them as 3/16 CCF. The old
style were "malleable", while the new style are said to be
"forged". I have found the newer style to be all but worthless.
One would be better off buying cheap wire rope clips from Ace
Hardware.
The older CCM clamps had a deep channel in the body of the
saddle, which positioned the dead end to overlay the live cable
under pressure from the U-bolt, so that all compression was
exerted between the two sections of cable. Instead of a real
channel, the newer CCF clamps have four bumps on the body of the
saddle, laid out in a rectangular configuration. The channel
formed between the bumps is too shallow to hold both segments of
cable in place so that one rides on top of the other; the dead
end tends to ride over to one side at about a 45 degree angle,
wedging partly against the body of the saddle instead of pressing
100% against the live cable. In addition, the older clamps had a
series of diagonal grooves at the bottom of the channel, designed
to grip the cable over the full length of the channel. The newer
ones have a single diagonal ridge, which pinches the live cable
in exactly the same manner as the U-bolt does when clamps are
installed the wrong way and the U-bolt b
ears down on the live cable. I did a test run with some newer
clamps, a piece of scrap cable and a come-along. I was able to
pull the cable tightly enough to cause it to slip through three
clamps with the nuts firmly tightened. I suspect this would have
been impossible with the older clamps; some piece of hardware
would fail or the cable would break before it would slip through
the clamps.
Furthermore, the U-bolts that come with these clamps are no
better than the saddles. The older ones were heavily galvanised,
like marine hardware. The newer ones are merely zinc-plated, just
like the aforementioned Ace Hardware product. About six months
ago I used some of the newer clamps for a less critical
application, to attach some pieces of guy cable anchoring the end
insulators of a wire antenna. Now, in little more than half a
year, the U-bolt nuts are completely rusted with no remaining
sign of zinc plating at all; in fact the nuts on these clamps are
already rustier than the older ones on a nearby tower that has
been up for more than 30 years.
I called this to the attention of a Rohn engineer, and his only
comment was that Rohn "no longer supports" the use of cable
clamps with guy wires; they now solely recommend Big Grips. He
said they only list clamps in the catalogue because they still
occasionally get orders for them. The illustration in the
catalogue clearly shows a picture of the older style clamps, not
the junk they sell now.
Does anyone know of a vendor who stocks original style heavily
galvanised clamps similar or identical to the older 3/16CCM?
Based on what I paid in 1980 and on-line inflation calculators,
these should now run a little over $1.00 apiece.
Don k4kyv
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