Protecting wire rope from abrasion is essential in lifting and rigging applications. Most types of wire rope are made of high-carbon steel wires that are twisted into strands. While they can typically handle a significant amount of weight — often thousands or even tens of thousands of pounds — they aren’t immune to abrasion. Fortunately, wire rope thimbles offer a simple and effective solution.
What Are Wire Rope Thimbles?
Wire rope thimbles are U-shaped rigging accessories that protect wire ropes from abrasion-related damage. Rather than running a wire rope directly through a lifting and rigging eye, you can run it through a thimble. The thimble will physically separate the wire rope from the eye, thereby protecting the wire rope from abrasion.
How Wire Rope Thimbles Work
With their U-shaped design, wire rope thimbles are able to wrap around lifting and rigging eyes. They fit into the loop formed when a wire rope is pulled back or otherwise carrying a load. The curved profile of wire rope thimbles controls the rope’s bend radius while simultaneously protecting it from abrasion.
As shown in the photo above, wire rope thimbles aren’t completely solid. The outer edge has a shallow groove. This groove is designed to hold a wire rope in place. You can use a thimble by running a wire rope rope into and around this groove.
Why Use Wire Rope Thimbles
If you’re worried that a wire rope will succumb to abrasion, you should consider using a thimble. Abrasion is one of the most common causes of rope failure in lifting and rigging. When a wire rope continuously rubs against a rough surface, it may wear down. If ignored, abrasion may cause the wire rope to completely fail. Wire rope thimbles offer a smooth, fitted surface for wire ropes, thereby protecting them from abrasion.
Wire rope thimbles also help to distribute loads more evenly. Without a thimble, the load is focused on the point of the rope’s natural bend, which is relatively small. With a thimble, though, the load is spread out across the entire thimble.
Choosing a Wire Rope Thimble
You can find wire rope thimbles in different styles. Light-duty thimbles, for instance, are typically thin and lightweight. They are designed for low-weight applications. Heavy-duty thimbles, on the other hand, are thicker and heavier, allowing them to withstand heavier loads.
Regardless of the style, you should choose a wire rope thimble in the right size. Be sure to match the thimble size with the size of the wire rope with which you intend to use it. If the thimble is too big, the wire rope will sit loosely in it. If the thimble is too small, the wire rope may not fit properly in the groove.