Choosing the Right Shackle for Your Chain Hoist
When you’re preparing for a lift, you’ve probably put time into choosing the right chain hoist based on its working load limit (WLL), lift height, and other desired performance features. But there’s one small part of the system that carries just as much weight that is easily overlooked – the shackle.
To help you make an informed decision about an appropriate shackle for your hoist, we’re explaining why shackle choice is critical, how to determine the correct fit, and critical specs about shackles you need to know.
What Is a Shackle?
A shackle is a U-shaped metal connector used in lifting, rigging, and load securement applications. It serves as the connecting point between your chain hoist and the object being lifted or the structure supporting the lift.
Anatomy of a Shackle:
- Bow (or body): The curved portion of the shackle.
- Pin: The removable component that closes the shackle.
- Ears: The ends of the bow where the pin threads through
Why Shackle Choice Matters
Proper shackle sizing and fit are critical to safety and load stability during overhead lifting.
Shackles are the critical link between your hoist and your load. If a shackle is too small, too weak, or improperly fitted, it can lead to point loading, unstable or misaligned connections, premature wear, or, in worst-case scenarios, lifting failure.
What Is Point Loading?
Point loading occurs when the force of a lift is concentrated on a small area of a lifting component, instead of the force being evenly distributed across the hook or shackle surface. In chain hoist setups, this most often occurs when the shackle is too small for the hoist hook and pulls toward the point of the hook, or if the load is not centered on the shackle.
There are several reasons why point loading is detrimental in chain hoist systems:
- Exceeds design limits: Shackles and hooks are designed to distribute force over a surface. Concentrating the force on a single point may overly stress the component.
- Increased risk of bending or cracking: concentrated stress leads to deformation, fatigue, or sudden failure after repeated use.
- Reduces load capacity: Point loading significantly reduces stated WLL. Most manufacturers don’t rate components for point loading.
Next, we’ll outline the specs you need to consider for a secure connection between your hoist and shackle.
The Specs You MUST Get Right
Shackle Type
There are two general types of shackles:
- Bolt-type – includes a bolt, nut, and cotter pin; ideal for lifting.
- Screw-pin – uses a threaded pin; better for temporary or non-lifting applications.
While you might come across screw-pin shackles regularly in rigging, they are NOT ideal for overhead lifting. For hoists, ALWAYS use bolt-type shackles with cotter pins and nuts to prevent loosening during use.
Bolt-type shackles provide superior load stability, prevent unintentional unthreading, and are ASME-compliant for overhead lifting applications.
Working Load Limit
Always choose a shackle with a working load limit (WLL) equal to or greater than the hoist’s rated capacity.
At USCC, we recommend selecting a shackle with a slightly higher WLL than your hoist. For example, if you’re using a 1-ton hoist, select a 1.5-ton or 2-ton shackle.
Even if your load weighs less than the hoist’s WLL, ALWAYS use a shackle with a WLL that corresponds to your hoist.
Opening Size and Shackle Pin Diameter
The shackle opening MUST be wider than the throat width of the hoist hook, but not overly wide. Look for a shackle opening that allows just enough clearance for a secure seat on the shackle. You’ll want to avoid a shackle so large that there is excessive movement at the connection point.
To avoid point loading, confirm the shackle pin diameter is appropriate for your hook. A pin diameter much smaller than your hook thickness will not sit evenly on the hook. Additionally, a shackle pin diameter far larger than your hook thickness will cause excessive play at the connection point, leading to an unsafe connection.
Final Fit Check – What to Look For
Before every single lift, verify the following:
- Shackle WLL markings are clearly legible, and shackle WLL is equal to or greater than the hoist WLL.
- No point-loading - The hoist hook sits securely on the shackle with its weight evenly distributed. The shackle doesn’t sit toward the hook’s point.
- No side-loading - The hoist hook should be within 5° of the shackle’s centerline
- All components are free from excessive wear, rust, or deformation.
Need Help? We’ve Got You.
Choosing the right lifting gear doesn’t have to be complicated. If you’re unsure which shackle fits your hoist, or want to double-check your setup, call our lifting and rigging experts at 866-444-9990 or email them at customerservice@uscargocontrol.com.
US Cargo Control: Your One-Stop-Shop for Lifting Gear
At US Cargo Control, we stock high-quality lifting and rigging gear, including chain hoists, shackles, lifting slings, and more. Plus, we offer same-day shipping on much of our gear and free shipping on orders $199+.
