Industry terminology

Working Load Limit (WLL): The maximum load weight the product is designed to support – in a straight pull situation, and in general usage. 

Proof Load (PL): The load weight that is applied during proof testing of the product. At this weight the product may not incur visual deformation. 

Minimum Breaking Load (MBL): The minimum load weight at which the product may no longer support the load, or may fail. 

Shock Load: A sudden and drastic force exerted on the product resulting from very rapid application. This is not a recommended practice due to increased stress on the product, adversely affecting the product’s life. 

Safety Factor: The ratio between the MBL and WLL. A safety factor of 6:1 indicates the product may only break once it’s overloaded by a factor of 6 – six times the designated WLL. 

Instructions for use

Before each use, shackles should be inspected to ensure proper safety measures. Things to note include:

• Legible markings
• Verify the pin and body are of the same size, make and type
• No damage to the body or threads on the pin
• Safety bolt type shackles MUST have the split cotter pin
• No distortion or unduly wear on the pin and the body, including gouges, nicks and corrosion
• Do not heat-treat, as WLL may be affected
• Never repair, modify or reshape shackles through welding, bending or heating, as WLL may be affected