Wire Rope Damage

[NathanK]

Thank you everyone for your opinions, I appreciate the different perspectives. We ended up having a new wire rope installed. This one is good. I was asking the technician why that happened and I was told the bolts for the rope anchorage clamps were stripped and they came loose. Just curious if that's plausible?

 

[Nige]

I was asking the technician why that happened and I was told the bolts for the rope anchorage clamps were stripped and they came loose.

OK, so according to the technician the rope anchorage clamp bolts on the drum (seeing as that's what your photos show) were "stripped".
I assume that he installed new ones.? Did he show you the old ones to back up his statement.? Were you billed for new anchor bolts.?
And then would he kindly explain just exactly how a problem with the clamping of the rope at the anchorage point on the drum would result in the damage shown in your original photos which was right at the opposite (dead end anchor) end of the rope.?

My opinion. I think he's full of sh1t.

 

[Nige]

Here's another question. How did he determine that the threads in the drum for the rope anchor clamp bolts were not damaged.?

 

[John C.]

Are you talking about the anchorage point on the drum itself or where the rope clamps are on the wedge socket? I can't see the clips and on the wedge socket clearly but think a clear photo might reveal a problem there.

 

[cranesafety]

I was told the bolts for the rope anchorage clamps were stripped and they came loose. Just curious if that's plausible?

I think its more likely that the socket head recess in the drum anchorage clip bolts were damaged (stripped) rendering them nearly impossible to remove with an Allen wrench. I have experienced this very scenario with these hoists. Alternative measures would be needed to extract the bolts (use your imagination) and YES, the bolts (and sometimes the clamps) must be replaced when this happens. If the hex recess is stripped, the bolts certainly could not be tensioned properly when re-installed.

Which raises the question: Why would anyone have re-installed those bolts and worse, why would anyone return the hoist to service if those bolts could not be properly tensioned? Now, with that said, I think Nige is correct in calling BS on that explanation. Don't see how that has anything to do with inducing twist at the dead-end. I would request documentation of the repair including any new parts used.

 

[Nige]

I would request documentation of the repair including any new parts used.

I'd request documentation backed up with before & after photos and a list of parts replaced.

I can't see the clips and on the wedge socket clearly but think a clear photo might reveal a problem there.

The original photos on Page 1 of the problem in the live end of the hoist rope give me the impression that 2 Crosby clamps along with a short piece of the rope had been used to add a safety to the dead end as per the illustration below which only has one clamp but it was all I could find.

 

[cranesafety]

a short piece of the rope had been used to add a safety to the dead end

You are correct and this is typically how the manufacturer specifies this termination be configured. There are manufacturer and model, specific tolerances for wedge protrusion below the socket, length of rope tail and distance between that short piece and the bottom of the socket. When done properly the termination is very reliable. I believe the cork-screwing effect in the rope was a result of installation error by failing to remove inherent twist from the rope manufacturing process prior to reeving it through the hoist and spooling on the drum. The installer was likely running behind schedule if struggling to remove those rope clips from the drum, leaving less time in the end to properly lay out all of the new rope, remove all twist and reeve the system. Hopefully the installer took the time to properly re-set the designed limit switches.

 

[crane operator]

Rope damage isn't from the drum termination bolts being loose. Once there's a couple wraps on the drum, the drum clamp doesn't hold much tension.

He's feeding you a line of B S. I think they installed it incorrectly, and are just covering their butts. But he has to tell you something....

 

[John C.]

The photo isn't clear enough to even see if there was a dead strip attached. It actually looks like the bottom clamp may be attached to the live side of the connection. I was always taught that the U bolt goes over the spacer rope and the clip side goes on the tail. The drawing is also showing the clip attached with the U bolt on the tail instead of over the spacer.

When installing a new line we always loaded the drum up first and then reeved in the hook block which would normally allow the twist to come out. That looks like someone tied the dead end and then loaded the line on the drum.

 

[NathanK]

I'd request documentation backed up with before & after photos and a list of parts replaced.
The original photos on Page 1 of the problem in the live end of the hoist rope give me the impression that 2 Crosby clamps along with a short piece of the rope had been used to add a safety to the dead end as per the illustration below which only has one clamp but it was all I could find.

View attachment 271704

Let me know if these pictures reveal anything. Thank you.

 

[Nige]

Let me know if these pictures reveal anything. Thank you.

Yes. They confirm what I thought.

I was always taught that the U bolt goes over the spacer rope and the clip side goes on the tail.

And that's what the photos show.

 

[John C.]

Are those the first replacement or the second. That is the way we were told to do the clips. I do question how far that wedge is sticking out the bottom of the socket though.

Maybe the crane guys can speak to that?

 

[Truck Shop]

Something I was told years ago by a rigging pro---Never saddle a dead horse,

 

[56wrench]

Thats true for eyes but in this case, the u-bolt has to grip the tail and the saddle the spacer piece. The rope will slip through the saddle easier than the u- bolt and in this case for safety, the tail must not slip through the clip otherwise it would defeat the purpose of the safety clip on the dead end of the tail. On an eye, if the rope slips through the clip on the live side, it will only make the eye smaller(tighter). Thats why we don’t saddle the dead side on an eye. If the dead side was saddled,it could pull loose

 

[Knepptune]

Thats true for eyes but in this case, the u-bolt has to grip the tail and the saddle the spacer piece. The rope will slip through the saddle easier than the u- bolt and in this case for safety, the tail must not slip through the clip otherwise it would defeat the purpose of the safety clip on the dead end of the tail. On an eye, if the rope slips through the clip on the live side, it will only make the eye smaller(tighter). Thats why we don’t saddle the dead side on an eye. If the dead side was saddled,it could pull loose

So your saying the clamps in the last photo are wrong?

 

[56wrench]

If you’re referring to the pictures in post#30 i would say they are wrong but i would do what the manufacturer of the crane/hoist specifies for legal/safety reasons. The illustration in Nige’s #26 post is what i would believe to be correct

 

[Nige]

Something I was told years ago by a rigging pro---Never saddle a dead horse,

But in this particular case there are two dead horses.........

If you’re referring to the pictures in post#30 i would say they are wrong but i would do what the manufacturer of the crane/hoist specifies for legal/safety reasons. The illustration in Nige’s #26 post is what i would believe to be correct

In the specific circumstances of the dead end rope coming off this anchor I can see the logic of installing the Crosby clamps "backwards" compared to the conventional way of installation.

 

[John C.]

What about how far the wedge is sticking out the bottom of the socket?

 

[Tones]

What about how far the wedge is sticking out the bottom of the socket?

That would suggest the Becket is to large for the rope I'm guessing.

 

[Nige]

To the OP. What brand is the hoist for your EOT crane.? Do you have an Owner's Manual for the hoist.?
It will generally not be the same as the manufacturer of the crane.