Two nearly identical slings, very different ratings?

Cole2534

Diamond

Joined

Sep 10, 2010

Location

Oklahoma City, OK

• Mar 9, 2019

• #1

I have 2 chain slings that are nearly identical but have different load ratings and I'm not sure why.

Sling 1 is 9/32 gr100, master link with 6' legs and hooks. Tagged at 7400WLL.

Sling 2 is 9/32 gr100, master link with 6" legs and hooks. Tagged at 6100 WLL (Basically a set of take-up hooks to be used with various chains).

The only difference is the leg length, although identical chain (peerless gr100), and hook style (grab vs self locking slip hooks). All fittings are cartec gr100.


What am I missing here?


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T

tdmidget

Diamond

Joined

Aug 13, 2005

Location

Tucson AZ

• Mar 9, 2019

• #2

Something is different. The manufacturers load rating is what you go by.

 

M

m16ty

Hot Rolled

Joined

May 11, 2016

• Mar 10, 2019

• #3

Everything is the same brand and from the same supplier? I wonder if one is rated for straight pull and maybe the other is rated for 60deg angle? Or maybe the safety factor is different?

When I buy my rigging, I get it from a local rigging company. They take the raw components (chain, rings, hooks, and connectors) and build them into what you require. After the sling is built, they have to look at the overall assembly to come up with a WLL. After that, they test to almost double the WLL, and then add the certification. I guess theoretically, each sling builder could come up with a different WLL, depending on their calculation method, safety factor, and testing procedure.

 

Cole2534

Diamond

Joined

Sep 10, 2010

Location

Oklahoma City, OK

• Mar 10, 2019

• #4

Just looked, all the same components all from the same well respected local rigging house.

The working angle is a good point, that's gotta be it.

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Cole2534

Diamond

Joined

Sep 10, 2010

Location

Oklahoma City, OK

• Mar 10, 2019

• #5

Sling angle was my answer.

7400 is a 30 degree rating, 6100 is 45deg.

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B

Bill D

Diamond

Joined

Apr 1, 2004

Location

Modesto, CA USA

• Mar 10, 2019

• #6

With only 6" legs that sling will be open at a wider angle for any two points. the wider angle reduces safe load.
Bil lD

 

N

number 2

Hot Rolled

Joined

Aug 13, 2009

Location

Western Australia

• Mar 27, 2019

• #7

Maybe the 6” leg is assuming not quite balanced conditions between the two legs. If You had two eye bolts one slightly higher it wouldn’t take much to transfer more load to one leg with such a short leg length.

 

R

Rob F.

Diamond

Joined

Aug 5, 2012

Location

California, Central Coast

• Mar 27, 2019

• #8

number 2 said:

Maybe the 6” leg is assuming not quite balanced conditions between the two legs. If You had two eye bolts one slightly higher it wouldn’t take much to transfer more load to one leg with such a short leg length.

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What do you mean? Please elaborate.

 

A

Alexjm

Plastic

Joined

Mar 25, 2019

Location

Edmonton, AB Canada

• Mar 28, 2019

• #9

You need to search the capacity of each load slings. Lifting high load with quality load slings without compromising on safety, quality or strength is always an ideal situation. However, if you are comproisiming on quality then it can create lots of problem. Length does matter but i think you need to focus on a relaibel manufecturer and then go with other requirement like length, legs and hooks.

 

M

m16ty

Hot Rolled

Joined

May 11, 2016

• Mar 28, 2019

• #10

Rob F. said:

What do you mean? Please elaborate.

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What he is talking about is a unbalanced load. If you have a pair of slings and each leg is on a different angle, the leg with the lesser angle will carry more of the load. I doubt this would be taken into account with the tagged WLL though.

All rigging I’ve ever seen will either be tagged with the WLL of different angles (usually straight, 60 deg, and 45 deg), or if they just have one WLL listed, that will be straight pull only, and you have to calculate your deductions for angles greater than straight.

They are also sometimes rated straight, choker, and basket. Even then, the rating is straight pull, and the different WLL is based on the hitch configuration.

 

N

number 2

Hot Rolled

Joined

Aug 13, 2009

Location

Western Australia

• Apr 7, 2019

• #11

Rob F. said:

What do you mean? Please elaborate.

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What m16ty said. If you had a block of steel, with two eye bolts next to each other, chances are during lifting only 1 leg will take the load. Same as if you have 4 leg sling arrangement, lifting a box from the top corners say, only 2, or depending on balance, maybe 3, but not four legs will take the load. If you use lifting beams to balance things that different,