[TowerTalk] cable clamp torque limit (summary)

[Pete Soper]

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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