Need 33K snatch block!!!

[Antichrist]

Industry standard and required for overhead lifting. Are you vertical lifting your rig during a recovery? The shackles have a WLL cast into them because they are designed for overhead lifting and are required to have a WLL in order to be sold in the US as rigging apparatus.

That was my point really.

The confusion is the multitude of safety factors, if any at all. Your shackles carry a 4:1, some hooks carry a 4:1 or 5:1 or 6:1. Then you have some blocks carrying anywhere between 2:1 through 5:1. Ignore the WLL cast into your gear. Find it's MBS and set your own safety factor and use the same factor for everything in your kit. That way YOU know what your equipment is rated for. 3:1 or 4:1 is sufficient.

All true.
My assumption (admittedly perhaps not a safe one) is that since Warn says "33,000lb capacity" the block has a 3:1 safety factor.

 

[bribassguy]

That was my point really.

All true.
My assumption (admittedly perhaps not a safe one) is that since Warn says "33,000lb capacity" the block has a 3:1 safety factor.

If you mean that the maximum strength is 3*33,000 => 99,000 You'd be very wrong.

I think in think case they are listing the Maxim Breaking (tensile) Strength as 33,000 and if you use the 6T WLL the safety factory is 33 000 / (6 * 2 200) = 2.5.

 

[Antichrist]

If you mean that the maximum strength is 3*33,000 => 99,000 You'd be very wrong.

Nope, not what I said.

I think in think case they are listing the Maxim Breaking (tensile) Strength as 33,000 and if you use the 6T WLL the safety factory is 33 000 / (6 * 2 200) = 2.5.

I said 3:1 because Warn says 33,000lb capacity. If 33k were the breaking load I don't think it would be too good to list it as the capacity.
In essence, my theory is that Warn is de-rating it by 3,000lb.

Of course, that's pure conjecture.
Maybe it's 4:1 and they are de-rating it by 15,000lb.
Or maybe they just picked a capacity value out of the air.

 

[bribassguy]

I think that's exactly whats wrong with recovery equipment ratings... you have no idea what they REALLY mean.

I get the impression that most are listed as maximum breaking strengths b/c most people think a 6T WLL is a whole lot less that 30,000 maximum capacity.

 

[Antichrist]

I get the impression that most are listed as maximum breaking strengths b/c most people think a 6T WLL is a whole lot less that 30,000 maximum capacity.

I'm sure that's the case. The vast majority of people buying recovery equipment don't have a rigging background and so have no idea the difference until someone points it out to them.

It would be nice if the Warn person on the forum would speak up and tell us what the safety factor is on their 6T WLL block.

 

[bribassguy]

It's just math to work out the safety factor, 33,000/(6*2200) -> 2.5

What we really need to know is if the 33,000 is a made up number or MBS.

 

[mogwildRW1]

My truck weigh's in at 13,000lbs, and the winch is rated to 5t, but will pull the truck with all 4 tires locked not a problem.

I purchased 2 of these from this ebay seller, he was great to work with.

http://cgi.ebay.com/New-Johnson-McK...105?pt=LH_DefaultDomain_0&hash=item35b064c671

That's a real snatch block :victory:

They were like new when I recived them, a vast price savings over purchasing the same thing new ($700-800 and up)

 

[Antichrist]

It's just math to work out the safety factor, 33,000/(6*2200) -> 2.5

Only if 33k is the MBS, which I think would be bad since they are saying that's the capacity. I'm of the opinion that people will think it's fine to use with a 33k lb load. Really bad news if that's the MBS.

What we really need to know is if the 33,000 is a made up number or MBS.

Definitely.

 

[Desert Drifter]

Thanks everyone for your input. I sent the Warn back to China!! Got an ARB 9000. Rated at 38,500#

Difference of night and day between the two!!!

 

[bribassguy]

Glad to hear you like it... I have always wondered about the plastic wheel.

Any initial thoughts?