I'm not convinced that a preform/thimble combo MUST be mated to a
straight cylinder, even though the examples shown don't include anything
but. I've seen BIG preforms installed through a closed link for example,
that seem to satisfy any concerns. As long as the curved link is smooth
(to avoid abrasion), it might offer an advantage over a straight pin.
At any rate, in ham applications it's mostly all academic.
-Steve K8LX
On 05/22/18 21:33 PM, Charles Morrison wrote:
This is the 4 page doc:
SP2049-5_BIG-GRIP_DE <dot> pdf
preformed.com/images/pdfs/Energy/Distribution/Guying_Products/Big-Grip_Dead-End/SP2049-5_BIG-GRIP_DE.pdf
http://preformed.com/images/pdfs/Energy/Distribution/Guying_Products/Big-Grip_Dead-End/SP2049-5_BIG-GRIP_DE.pdf
On Tue, May 22, 2018 at 9:30 PM, Charles Morrison <junkcmp@gmail.com> wrote:
If you read the info provided with PREFORMS / BIG GRIPS, you see that all
curved surfaces (inside thimbles and the curve side of shackles) should be
mated to flat /straight surfaces like: (equalizer plate bolts, the rod/pin
of a shackle.) See page three of this document. Here's the link:
Filename Big-Grip_DE-PLP_CommCatSec20 <dot> pdf
preformed.com/images/pdfs/Communications/Pole_Line_Hardware/Dead-ends__
Accessories/Big-Grip_Dead-end/Big-Grip_DE-PLP_CommCatSec20.pdf
http://preformed.com/images/pdfs/Communications/Pole_Line_
Hardware/Dead-ends__Accessories/Big-Grip_Dead-end/
Big-Grip_DE-PLP_CommCatSec20.pdf
The only exception to this rule is you may use a curved shackle to a
curved shackle. This guide also suggests that you should not force a
thimble into the downward end of a torque bar, but use the pin/rod of a
shackle.
Review the "arrangement" illustrations shown on page 4: Arrangement A
through G.
-Charlie N1RR
On Tue, May 22, 2018 at 7:56 PM, Steve Maki <lists@oakcom.org> wrote:
Only if you use too-small thimbles. Properly sized thimbles for your
properly installed big grip will be...just right! Big enough radius so it
doesn't fall out, and strong enough to not compress from wire tension.
BTW it's common to terminate a big grip (with thimble) to a pin shackle
for attaching to guy weldments, etc. I usually use a shackle for coupling
my non-conductive guy to the bottom EHS wire, just for a little extra
flexibility.
-Steve K8LX
On 05/22/18 19:11 PM, Chuck Dietz wrote:
The problem with using two back-to-back thimbles is the radius is too
small. It needs to “wrap around” something larger. Many thimbles would end
up squeezing together so that the guy grips would be out of specs by the
small radius. It would only be slightly better than guy grip to guy grip.
Also, when you need to take the guy loose, what will keep the thimbles from
coming out? If you really clamp down on the guy grip, it will be out of
specs. Maybe I am not acquainted with the type of thimbles you are talking
about. You would need to check the thimble specs.
Using the insulators keeps everything in spec, but they are heavy.
Chuck W5PR
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