Rigging screws and turnbuckles, also known as straining screws or bottlescrews, are a simple piece of equipment used to adjust the tension of wires and ropes or to secure loads.
Rigging screw and turnbuckle are interchangeable terms, commonly the term rigging screw refers to a fitting with an enclosed body hiding the threaded section, whereas a turnbuckle will have an open body, exposing the threaded section. Both fittings can be used under the same application but turnbuckles are generally smaller and have a greater ability to be tightened under load.
To use a rigging screw and turnbuckles you attach the wires or ropes than need to be tensioned to the fittings at either end. Rotating the body of the rigging screw pulls the ends towards one another, causing the rope to tighten, or away from each other, causing it to loosen. This piece of equipment can have different ends depending on your needs – hooks, eyes or jaws, or a combination of two of these. Jaws usually have pins to keep them securely in place and eyes are available in a range of diameters. Closed body fork (or jaw end) rigging screws can be directly attached to an eyebolt without the need for extra shackles or fasteners. Rigging screws can also be swaged (crimped) to wire rope.
Rigging screws are used in applications where a rope needs to be held at a certain tension. They can also vary in thread size, depending on the size of the rope. You'll have seen them in action on the ropes around a boxing ring, the cables of a suspension bridge or in the rigging of a boat.
Available in steel and stainless steel with a galvanised or polished finish and a range of open and closed lengths.