What should NEVER be substituted for the alloy pin of a shackle?

• A. A common bolt
• B. A rated pin from the same type of shackle
• C. An approved manufactured pin
• D. DA bolt

Answer: (A)

In rigging, the pin and the shackle work together as a rated load path, so the pin must be manufactured to the exact size, material grade, and threading for that specific shackle. A common bolt should never be substituted because ordinary bolts are not made to those exact tolerances or strength requirements. They may not fit properly, can shear or bend under load, and their threads or locking features may not behave safely under dynamic conditions, risking the pin loosening or the load dropping. Using a rated pin from the same type of shackle or an approved manufactured pin ensures the pin matches the shackle’s dimensions and strength, maintaining the stated working load limit and safe operation.