Connecting Shackle to Shackle
The popular Crosby forged chain and anchor shackles (3/16” – 3”) can be point to point loaded to the Working Load Limit without bending of the pin/bolt. Connecting bow to bow, or bow to pin is the preferred method. Connecting pin to pin is also acceptable if there is not interference between the diameter of the shackle ears.
No matter which method is used, caution should be given to maintain the load at the center of the span, by spacers on the shackle pin if necessary, to prevent the load or attaching shackle from sliding over to one side and concentrating loading near the shackle ear.Keeping the load reasonably centered is key.
Tightening the Pin in a Screw Pin Shackle
First, Crosby states that screw pin shackles are to be used in pick and place applications.
Second, the pin must be tight before each lift and must not be able to be rotated while in use.
ASME B30.26 has the following statement regarding screw pin shackles:
The screw pin threads shall be fully engaged and tight and the shoulder should be in contact with the shackle body.
Thus, contrary to popular believe, you should never back off the screw pin before use. The shackle pin should be a minimum of hand tight before the lift begins.
Always make sure the shackle pin is tight!
If the screw pin cannot be threaded into the shackle by hand, this may be the result of deformation.
Note: For permanent or long-term application, use a bolt type shackle with bolt, nut & cotter or in any application that a screw pin shackle is used.
