Screw Pin vs Bolt Type vs Round Pin Shackle

Author：Solidlink Hot：

A shackle's rating is only as good as its pin. The pin is what actually holds the load, and choosing the wrong type can seize up, work loose, or fail under vibration. This guide explains the three main pin types and how to pick the right one.

What Is a Shackle Pin?

A shackle pin is the removable cross-member that closes the opening of the shackle body. It takes the full load of the connection and must be matched to the shackle size, the load, and how often the connection is opened.

Types of Shackle Pins

Screw pin: a threaded pin that screws directly into the shackle body. Fastest to rig by hand, ideal for temporary or frequently changed connections such as slings and chokers.
Bolt type: a smooth pin held by a nut and cotter pin. Stronger and more secure, used for permanent or high-load rigging where vibration is a risk.
Round pin: a plain pin hammered into place and held by a lanyard. Common in marine use and wherever quick release matters.

How to Choose a Shackle Pin

Match the pin to the shackle size — never use an undersized or improvised pin.
Use a screw pin for slings and chokers that change often.
Use a bolt type where the connection is permanent and vibration is a risk.
Confirm the pin diameter fits the sling eye, hook or anchor.

Inspection

Before each lift, check the pin for bent threads, worn threads, corrosion and a loose fit. A pin that binds or spins freely must be replaced. Never substitute a standard bolt for a rated shackle pin.