I got no numbers or anything objective back from your collective wisdom in
response to my questions about cable clamps and "how tight is tight." I broke
another one two nights ago so the tally is now three failures out of 51 1/4CCM
clamps (48 installed). The last failure was with a torque wrench in place,
reading 32 foot pounds. This corresponded pretty closely to the "really tight"
torque levels I'd been applying with a 6" ratchet wrench when the other two
failed.
I described this situation to Steve at Hill Radio today and he told me "if
you're crimping the cable, that's too tight." I hadn't expected to find that I
could make these things too tight with a little wrench, but there you are. I'm
sure the cable was crimped a bit by the u-bolt portion of the clamp in some
cases, so I guess this is operator error.
At this point it's clear this is art and not science, but I guestimate 20-25
foot pounds is appropriate for Texas Towers and Hill Radio "1/4CCM" clamps put
on in groups of three.
Thanks to Gerald K5GW of Texas Towers for suggesting I submit this issue to the
reflector.
I realize clamps are passe. A couple dozen of you have made this clear. Message
received. The second tower will have Philly instead of EHS and insulators,
grips instead of clamps: perfect in every respect :-)
Regards,
Pete
KS4XG
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