Wire rope clamps.

[Putter]

From another thread I learned that these clamps have a specified direction for install. U bolt on the short end. "Don't saddle a dead horse". I am installing 1/2 " cable in my roof system right now. Does anyone know what these clamps should be torqued to? I certainly don't want to over-torque it and ruin my cable. Thanks for any help.

Quote from post-pounder thread.

This is in the "just so you know department" not being critical here, but in using the wire rope clamps, (yes I know that is not wire rope) the minimum number is 3 and the way to put them on is so that the "dead end" is adjacent to the U clamp not the saddle part of the clamp. as in the old saying "Do not saddle a dead horse" as a way to remember it. The top ones are correct (but need 3) the bottom ones are incorrect, I am not sure how well they will hold with the nylon rope, but probably OK. Again not trying to start anything, just passing along standard practice.

James K0UA

http://www.sbic.com/smos/may06/smo060503.pdf

 

[beppington]

Interesting that no reason is given.

Why would it matter whether the U-bolt is on the line side or the dead end side?

 

[JerryK]

Interesting that no reason is given.

Why would it matter whether the U-bolt is on the line side or the dead end side?

The U-bolt pinches the dead side cable, and would do the same and weaken the live side. In an earlier life, we used to tighten the nuts....wait a few....tighten them some more....and repeat. You can probably get them too tight, but too loose is also bad. We did not have any torque info...but you can probably go to Crosby, or what ever manufacturer you are using, and ask them. You should also use at least two clamps on each end.... don't ask me why, but that is what I was taught when I was an apprentice...many moons ago...in an earlier life. Three sound good, too....maybe that is the standard now....

 

[beppington]

The U-bolt pinches the dead side cable, and would do the same and weaken the live side.

I don't understand how it's OK to weaken the dead side. Being that this is one rope, a weak spot or break anywhere would seem very bad ... no?

 

[JerryK]

I don't understand how it's OK to weaken the dead side. Being that this is one rope, a weak spot or break anywhere would seem very bad ... no?

My GUESS is that the live side is carrying the full load, and the pinched dead side is cushioning this more important side. The dead side is only possibly carrying half the load, since the loop thru the eyelet or whatever goes to both live and dead side...and is only carrying half the load, split between the two. Heavy on the GUESS.....

 

[beppington]

My GUESS is that the live side is carrying the full load, and the pinched dead side is cushioning this more important side. The dead side is only possibly carrying half the load, since the loop thru the eyelet or whatever goes to both live and dead side...and is only carrying half the load, split between the two. Heavy on the GUESS.....

Will I guess that makes sense.

View attachment giggle.bmp

 

[Combustix]

The rounded part of the clip does go on the standing wire or short wire, and should be spaced at equal distance 6 times the diameter of the wire apart. For 1/2 in wire you only need 2 clips but three is always better. As far as tightening torque away, then when you put the wire under a strain give it one more go at tightening, if this is going to be standing rigging you are good to go. If you are using it for loads then you need to check on your clamps periodically. Also keep an eye on the clamp farthest from the eye, as this will be the first to give way.

 

[bcp]

Clamping instructions and torque table:

Crosby Wire Rope Clips - Warnings and Safe Installation Instructions

Bruce

 

[CurlyDave]

Interesting that no reason is given.

Why would it matter whether the U-bolt is on the line side or the dead end side?

The tensile force on the dead end is much less than the force on the live end.* The U-bolt is going to produce some damage to the cable, and you want this damage on the low-force part of the cable.

*The reduction in force of a cable wrapped around a cylinder is enormous. Think about what happens when you wrap a rope around a tree. With even one turn you can prevent large animal, like a horse, from pulling the rope out of your hands.

With wire rope and an eye you are only getting 1/2 turn around the eye, but the reduction in force is still very large.

 

[Putter]

Excellent! Thanks for the link.