There is a tool (forgot the name) that will put a substantial flair
...flare...in the ends of the EMT. Easy to make. Actually, one of the
tools used for flare fittings would suffice. Not as big a flare, but
sufficient. Easier to use, too!
73
Roger (K8RI)
On 6/6/2015 10:43 AM, Patrick Greenlee wrote:
At $22 each I'd just as soon Whip up a DIY solution.
First thing that comes to mind is a short length of galvanized steel
tubing like EMT or similar, larger in ID than the OD of the coax. I'd
drill a some holes in the tube in the bottom 1/4 of its length to
accept some sheet metal screws and another hole say 3/8 of an inch
from the end opposite the screws. This last hole is sized to take a
length of wire with which the assembly is suspended (I'd size the
hole to take 3-4 passes of the "seizing wire.")
With a grinder, file, or other means, dull (remover the sharp point)
from the sheet metal screws so that when screwed into the
aforementioned holes (don't have to be screwed in all the way) room
is left for the coax. Tap the end with the screws with a hammer to
make for a snug but not tight enough fit so as to deform the coax.
Roughen the coax jacket for good traction (60-80 grit) where it will
contact the potting compound. Insert the coax, adjust the screws so
they are not deforming the coax. Pour in your catalyzed potting
compound. You could use the polyester fiberglass type resin, or epoxy
or the "Hobby Lobby" grape casting stuff...
Howzit work?
The potting compound grips the roughened coax jacket. The weight of
the suspended coax pulls down on the coax inside the do-dad trying to
pull the potting compound and coax out the bottom. The screws are in
shear, resisting the downward motion of the potting compound. The ID
of the EMT or whatever is less at the bottom of the do-dad than the
top thanks to your hammer taps so any attempt at downward motion of
the potting compound relative to the EMT results in radial
compression of the potting compound making it grip the coax tighter
for better traction.
This is a first cut at a cheap coax hanger. Please feel free to
improve on it but please don't run the cost up a bunch.
If I could whip this out in 5 min off the top of my head then surely
some of you smart guys could polish it up sufficiently to prep it for
use. I think it should be doable for a couple bucks or so each. A few
minutes of messing about with simple tools could make for a decent
savings while making for a little shop fun.
No claim is made for having any beneficial effect on center conductor
creep.
Patrick N5G
On 6/5/2015 12:04 PM, Robert Harmon wrote:
Me again.
FWIW, these are the cable strain relief grips I use. One nice thing
about these is you dont have to
rull the cable through to attach as you do with the braided ones.
These install right on the side of the cable easily and the sliding
tapered clamp grips very well from the
weight of the cable. I have been using them for years and no problems.
They are made by Hubbell I believe rather than Kellem.
http://www.amazon.com/GARVIN-CHOKR1-WEDGE-CLAMP-ACSR/dp/B007886EDO
<http://www.amazon.com/GARVIN-CHOKR1-WEDGE-CLAMP-ACSR/dp/B007886EDO>
Bob
K6UJ
On Jun 5, 2015, at 8:43 AM, Robert Harmon <k6uj@pacbell.net> wrote:
I agree Rick.
I use the Kellems and they work great.
BTW, I want order some more but I use the sliding clamp type not
the braided ones.
Only see the braided ones now when I search on line.
They only make the braided ones now ?
Bob
K6UJ
On Jun 5, 2015, at 7:39 AM, Richard (Rick) Karlquist
<richard@karlquist.com> wrote:
On 6/5/2015 7:20 AM, Patrick Greenlee wrote:
educe damage to the coax.
I haven't done/tried the following but solicit comments from those
who
have:
Use a large radius of curvature 90 degree section of conduit to
increase
the area of contact between the coax and conduit. Use an adhesive
(spray adhesive sold for attaching auto trim or other good
adhesive) to
why go to all this trouble when you can use a Kellems grip to hold
the coax?
Rick N6RK
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Roger (K8RI)
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