[Kawierider]

Please explain the use of a chain,( i.e. anchor or pivot point) and if you have a link, the ways of identifying grades of chains.
For example; the chain that came with the Warn recovery accessory kit.

Some explanation of the differences in straps; i.e. a "jerk" strap vs "tow" strap vs air "sling" strap.

I witnessed an incident where a chrome front tow hook literally snapped in the middle of the bend from it's front bumper mount and rocketed through the back end of the pulling CJ, and a spare battery in the rear, into the rear seat.

Chrome plating because it is so brittle will weaken an otherwise strong fixture. This may explain the failure you witnessed. But that is a good point; I would never chrome anything that will see forces of the magnitude involved in recovery, or something that will see high frequency low amplituded (think vibration) stresses applied.

 

[Kawierider]

Here is an EXCELLENT article on offroad recovery. It is from Bill Vista over at pirate4x4. This has many excerpts from the military recovery manual and other quality sources of information like wire and strap suppliers.

Also has the charts that were mentioned above.

http://www.pirate4x4.com/tech/billavista/Recovery/

 

[Kawierider]

Grandman,
Do you insist on the screw type shackles for fear of the cotter pin shearing out of the pin type if the load gets offset?

 

[Kawierider]

Marv,
Good post. No arguements from me. As already stated, there are actually 2 different ways to attach two straps together but I don't have any pics. (this makes my post lame I know)

Regarding the chrome hook breaking.... I would agree with Marv that it is probably a cheap aftermarket hook. But, the chrome platint DOES NOT weaken the material underneath. Chrome plating does not use heat and therefore will not anneal or draw back a hardened material. In addition, cosmetic chrome is only .0005" to .002" thick.

It does not weaken the material due to a change in heat treatment. It weakens the material because when the hook (in this case) flexes the chrome plating will form small cracks (because it is so brittle). these cracks concentrate stresses on a very very small area. this intense area of stress will propogate a crack more readily than a non-plated piece. Usually, this is a theory applied to fatique fractures, but without knowing the history of the hook I can't obviously tell you if this was the case or not.

I also concurn though. it probabley was a cheap aftermarket hook.