What Are Rigging Shackles
In the world of rigging, shackles are an undeniable must when completing a wide array of suspension and support projects. From bridges and communications towers to sunshades and tree planting, the shackle is the link connecting them all. Below you’re going to learn about shackle anatomy, common material and coating types, shackle types, shackle use cases, and other basic information to help you select the best shackle for your application.
Shackles are a type of rigging fitting that’s used as an attachment component for lifts or suspension.
A common example of how shackle would be used is attaching a turnbuckle to an eyebolt. These components are closed making them strong and reliable, however an equally strong link must be made to achieve connection. A shackle is that linking component.
When referring to shackles, it’s important to know that right nomenclature. The “bow” indicates the top or closed end, the “ears” refer to the open end and where the pin slides or screws through, and lastly, the “pin” slides or screws through the ears to close off the connection. Specifications of these parts of the shackle are important to know in the project planning stage. On our site you can find each shackles’ dimensions in their respective product pages to make sure you make the right purchasing decision.
Shackle Working Load Limit and Side-Loading
On any given rigging project, safety is of the highest importance. When putting a rig together, always consider working load limits and load configuration. NOTE: Refer to ASME B30.26 for all guidelines
pertaining to overhead lifting and suspension.
WLL Always ensure that the selected shackle meets or exceeds the working load limit for each specific task and is comparable to the Working Load Limit (WLL) of other rigging hardware being used in the lift or suspension.
Side-Loading Whenever a shackle is used to pull or lift a load at an angle greater than 5° from the shackle’s centerline, it is referred to as “side-loading”. All side-loading comes with specific load reduction that must be factored into the WLL of the rig. For example, if the shackle is loaded at any angle from 6° - 45°, that shackle WLL should be reduced by 30%. From 46° - 90°, the WLL will be reduced by 50%. Loading at any angle over 90° is NOT recommended.
Varieties of Shackles
Over the years, shackles have taken on plenty of unusual and often bizarre shapes to best perform in specific applications.
These shackles are the most recognizable and versatile shackles by far. They can be side- or cross-loaded when factoring in load reductions to the in-line working load limits.
Bow-type shackles technically fall under the anchor category but are used for the bow’s increased radius to prevent a web sling from kinking or bunching during a lift.
The Chain or D-type Shackle is recognized for its slimmer bow, making a “D” shape when held on its side. It’s designed to connect to chain and rated for in-line tension only. When in use, the center of the load should always coincide with the center line of the shackle.
This catch-all category includes task-specific shackles like sheet pile shackles, designed for lifting sheet piles out of the ground, and snap shackles for securing main sheets and halyards on sailing vessels.
Shackle Pin Varieties
When lifting and suspending with shackles, it’s important to understand the function and the application of the two pin varieties.
This variety refers to a threaded pin that slides through the two unthreaded ears of the shackle after which is secured by a combination nut and cotter pin. The nut should be tight up against the ear and the cotter pin ends should be bent back. When properly installed, you’ll have a safe, semi-permanent connection that’s suitable for overhead lifting and suspension.
A screw pin shackle features a single ear that is threaded to receive a matching screw pin for a closed connection. This shackle is convenient for temporary overhead lifting and pick-and-place tasks since the screw pin is quick and easy to open or close. Prior to every lift, hand-tighten the screw pin to ensure the shoulders of the pin are contacting the shackle’s ear, and the threads are fully engaged. In the case that the screw-pin shackle is exposed to vibration, mousing can be used as backup securement.
Shackle Material and Coating Types
With shackles, one-size will not fit-all, and the same is true for coatings and materials. When selecting a between galvanized steel, powder coated, and stainless-steel it’s important to consider the environment to which your shackle will be exposed.
Galvanized steel shackles are the most basic, all-around, and cost-effective shackle type. They’re used in most general-purpose applications whether indoors or out in the elements. While corrosion resistance is moderate, many find it easy to inspect and maintain. Most are made with strong steel which attributes a high working load limit.
These black oxide steel shackles are a step above simple hot-dipped galvanized. Many choose these shackles for dynamic rigs and repeated movements since the coating is highly durable.
When corrosion is the main concern, stainless steel shackles are the way to go. While not as strong as steel, they perform well in and around saltwater and other reactive environments. Stainless-steel is the best at resisting corrosion, however it could rust over time, so we strongly recommend maintaining and cleaning this shackle type periodically.