Hiya PeeBee
My bad perhaps I shouldn't have used the term "rating" it probably should have been breaking strain...
The following is the gist of some of the documents I have here which admittedly aren't exactly the latest 'cept the Bullivants one:-)
From Bullivants
http://www.bullivants.com/FlippingBo...ublication.pdf...
The pin is screwed tightly with the collar and the pin is
bedded evenly on the surface of the shackle eye.
From CM Rigging...
-How tight does the pin need to be?
The pin must be tightened hand tight or until pin
head is fully seated against the body of the shackle.
It may be necessary to tighten an additional 1/8 turn
to ensure proper engagement. Do not back the
pin off the body of the shackle.
MOUSE TAIL SHACKLE IF IT REMAINS IN
PLACE FOR ANY EXTENDED PERIOD OF TIME.
THIS WILL PREVENT PIN FROM BACKING OUT
From an internal publication on Rigging Fundamentals (source unknown) for our restraint and anchoring applications...
Shackles shall not be used if the pin cannot be completely seated.
The pin need be only hand tight for lifting.
Use only shackles with screw pin, round pin with cotter should not be used.
Screw pin shackles shall not be used if the pin can roll under load and unscrew
Disclaimer... I don't do Crane Lifts and I am not a Rigger, Doggy or Craney and don't have any issue at all with how any Statutory bodies indicate how equipment is to be used for lifting IE if they say it can be backed off then I have no probs with that.
As I do not have any of the above training or quals I therefore use gear as per the manuf or supplier recommendations/suggestions/practices IE all the screw pin shackles I use in restraining, anchoring or for handling any of my gear are rated, tightened and moused.